EPIDEMIOLOGY OF INFLUENZAVIRUS A (H₅N₁)

Table of contents :

(a) close contact (within 1 m) with a person (for example: caring for, speaking with, or touching) who is a suspected, probable, or confirmed H₅N₁ case;

(b) exposure (for example: handling, slaughtering, defeathering, butchering, preparation for consumption) to poultry or wild birds or their remains or to environments contaminated by their feces in an area where H₅N₁ infections in animals or humans have been suspected or confirmed in the last month;

(c) consumption of raw or undercooked poultry products in an area where H₅N₁ infections in animals or humans have been suspected or confirmed in the last month;

(d) close contact with a confirmed H₅N₁ infected animal other than poultry or wild birds (e.g. cat or pig);

(e) handling samples (animal or human) suspected of containing H₅N₁ virus in a laboratory or other setting.

Probable definition 1: a person meeting the criteria for a suspected case AND one of the following additional criteria:

a. infiltrates or evidence of an acute pneumonia on chest radiograph plus evidence of respiratory failure (hypoxemia, severe tachypnea) OR

b. positive laboratory confirmation of an influenza A infection but insufficient laboratory evidence for H₅N₁ infection.

Probable definition 2: a person dying of an unexplained acute respiratory illness who is considered to be epidemiologically linked by time, place, and exposure to a probable or confirmed H₅N₁ case.

• a. Isolation of an H₅N₁ virus;
• b. Positive H₅ PCR results from tests using 2 different PCR targets, e.g. primers specific for influenza A and H₅ HA;
• c. A 4-fold or greater rise in neutralization antibody titer for H₅N₁ based on testing of an acute serum specimen (collected 7 days or less after symptom onset) and a convalescent serum specimen. The convalescent neutralizing antibody titer must also be 1:80 or higher;
• d. A microneutralization antibody titer for H₅N₁ > 1:80 in a single serum specimen collected at day 14 or later after symptom onset and a positive result using a different serological assay, for example, a horse red blood cell hemagglutination inhibition titer of 1:160 or greater or an H₅-specific western blot positive result.

• (1) Four South Koreans were infected with the H₅N₁ strain of bird flu in late 2003 and early 2004, but none of them developed any serious illness, an official said 24 Feb 2006^ref
• (2) 3 asymptomatic infections have been documented among close contacts of confirmed cases in Viet Nam suggesting that milder H₅N₁ infections are occurring. Four persons who culled H₅N₁ infected birds in Japan and 2 animal attendants caring for infected tigers in Thailand also have antibodies to H₅ virus. Asymptomatic infections were also detected retrospectively in Hong Kong following the 1997 outbreak^ref
• (3) On 9 Mar 2005 Vietnamese health authorities released information about 2 such cases. Nguyen Tran Hien, director of the National Institute for Hygiene and Epidemiology, confirmed that lab tests showed that a 61-year-old woman from northern Thai Binh province had contracted the H₅N₁ virus but was not showing any symptoms^ref
• (4) 2 elderly relatives of people in Vietnam who died of bird influenza have tested positive for the disease, despite having no symptoms. Samples from another 7 cases that originally tested negative in Viet Nam in January were re-tested in Tokyo and found to carry the virus, according to the World Health Organization^ref.
• (5) Dr Charoen Chuchottaworn, a bird-flu expert at the [Thai] Public Health Ministry's Department of Medical Services, said doctors concluded after reviewing the history of the past 2 cases that bothvictims presented very mild symptoms of avian influenza and neither had any physical contact with chickens or birds^ref

While much has been made of the fulminant cases of presumed viral pneumonia in 1918, Dr. Brundage's research indicates that the majority of pneumonia cases, even in 1918, were either secondary bacterial pneumonias following an influenza infection or mixed viral and bacterial pneumonias. In the pre-antibiotic era, these cases of bacterial pneumonia carried a very high mortality rate; however, with appropriate antibiotic therapy, many such patients may be saved. There is still a deficit of comprehensive seroprevalence data to establish the true frequency of subclinical infections and the relevance of these sporadic accounts of atypical infections listed above.

• in 1997 : 18 cases (6 deaths) ranging in age from 1 to 60 years, had gastrointestinal symptoms, hepatitis, renal failure, and pancytopenia. Clinical presentation was that of an influenza-like illness with evidence of pneumonia in 7 patients. All 7 patients > 13 years had severe disease (4 deaths), whereas children 5 years or younger had mild symptoms with the exception of one who died with Reye's syndrome associated with intake of aspirin. Gastrointestinal manifestations, raised liver enzymes, renal failure unrelated to rhabdomyolysis, and pancytopenia were unusually prominent. Factors associated with severe disease included older age, delay in hospitalisation, lower-respiratory-tract involvement, and a low total peripheral white blood cell count or lymphopenia at admission. An H₅-specific RT-PCR was useful for rapid detection of virus directly in respiratory specimens. A commercially available EIA was more sensitive than direct immunofluorescence for rapid viral diagnosis. Direct immunofluorescence with an H₅-specific monoclonal antibody pool was useful for rapid exclusion of H₅-subtype infection^ref. The kinetics of the antibody response to the avian virus in H₅N₁-infected persons was similar to that of a primary response to human influenza A viruses; serum neutralizing antibody was detected, in general, >/=14 days after symptom onset^ref. > 1.4 million chickens and other birds in the open-air markets of Hong Kong were slaughtered in 3 days by trained government workers (GWs), most of whom wore protective masks, gloves, and gowns. Although exposure to live poultry was associated with human illness, no cases were documented among poultry workers (PWs). To evaluate the potential for avian-to-human transmission of H₅N₁, a cohort study was conducted among 293 Hong Kong GWs who participated in a poultry culling operation and among 1525 PWs. Paired serum samples collected from GWs and single serum samples collected from PWs were considered to be anti-H₅ antibody positive if they were positive by both microneutralization and Western blot testing. Among GWs, 3% were seropositive, and 1 seroconversion was documented. Among PWs, approximately 10% had anti-H₅ antibody. More-intensive poultry exposure, such as butchering and exposure to ill poultry, was associated with having anti-H₅ antibody^ref. Avian-to-human transmission of influenza viruses is believed to be infrequent because of host barriers to infection, such as cell receptor specificities, and because the acquisition by avian viruses of the ability for human-to-human transmission requires either genetic reassortment with a human influenza strain or genetic mutation^ref. However, a cohort study of household and social contacts of Hong Kong H₅N₁ case-patients found evidence, although limited, for human-to-human transmission. By use of a combination of serologic assays, 6 of 51 household contacts, 1 of 26 tour group members, and none of 47 coworkers exposed to H₅N₁-infected persons were positive for H₅ antibody. One H₅ antibody-positive household contact, with no history of poultry exposure, provided evidence that human-to-human transmission of the avian virus may have occurred through close physical contact with H₅N₁-infected patients. In contrast, social exposure to case patients was not associated with H₅N₁ infection^ref. Further evidence was provided by a study of healthcare workers (HCWs), which found that significantly more HCWs exposed to patients with H₅N₁ infection were seropositive for H₅ antibody than nonexposed HCWs (8 (3.7%) of 217 exposed vs. 2 (0.7%) of 309 nonexposed HCWs (P=.01)); 2 HCWs seroconverted after exposure to H₅N₁-infected patients, in the absence of known poultry exposure^ref. These 2 studies provided the first evidence, although limited, of human-to-human transmission of H₅N₁ viruses of purely avian origin.
• in February 2003 : 2 cases (1 death). Waterfowl are the natural reservoir of all influenza A viruses, which are usually nonpathogenic in wild aquatic birds. However, in late 2002, outbreaks of HPAI H₅N₁ caused deaths among wild migratory birds and resident waterfowl, including ducks and flamingos^ref, in 2 Hong Kong parks. Several thousand chickens were slaughtered. 2 members of a same family who returned to their home in Hong Kong on 8/2 after being exposed to chickens in Fujian province, mainland China, during the Chinese New Year were affected. The 8-year-old daughter died on 4/2 whilst the family was in Fujian and the 33-years-old father of the family developed respiratory symptoms on 7 Feb whilst in Fujian : he was admitted to hospital in Hong Kong on 11/2 with pneumonia and died on 17/2. Influenza A (H₅N₁) was isolated from post-mortem specimens on 20/2. The man´s 9 year old son also became unwell whilst in Fujian province : he was admitted to hospital in Hong Kong SAR on 12/2 with pneumonia. Influenza A (H₅N₁) was isolated from 2 nasopharageal aspirates taken from the boy on 19/2. The mother recovered from what was thought to have been a parainfluenza infection. The mother and children were in mainland China for 14 days; the father for 9 days. Antigenic analysis of the new avian isolates showed a reactivity pattern different from that of H₅N₁ viruses isolated in 1997 and 2001. This finding suggests that significant antigenic variation has recently occurred among H₅N₁ viruses. In contrast to H₅N₁ viruses isolated from humans during the 1997 outbreak in Hong Kong, A/Hong Kong/213/03 (HK213; H₅N₁) retained several features of aquatic bird viruses, including the lack of a deletion in the neuraminidase stalk and the absence of additional oligosaccharide chains at the globular head of the hemagglutinin molecule. It demonstrated weak pathogenicity in mice and ferrets but caused lethal infection in chickens. The original isolate failed to produce disease in ducks but became more pathogenic after 5 passages. Taken together, these findings portray the HK213 isolate as an aquatic avian influenza A virus without the molecular changes associated with the replication of H₅N₁ avian viruses in land-based poultry such as chickens. This case challenges the view that adaptation to land-based poultry is a prerequisite for the replication of aquatic avian influenza A viruses in humans^ref. When mallards were inoculated with antigenically different H₅N₁ influenza viruses isolated between 1997 and 2003, the new 2002 avian isolates caused systemic infection in the ducks, with high virus titers and pathology in multiple organs, particularly the brain. Ducks developed acute disease, including severe neurological dysfunction and death. Virus was also isolated at high titers from the birds' drinking water and from contact birds, demonstrating efficient transmission. In contrast, H₅N₁ isolates from 1997 and 2001 were not consistently transmitted efficiently among ducks and did not cause significant disease. Despite a high level of genomic homology, the human isolate showed striking biological differences from its avian homologue in a duck model. This is the first reported case of lethal influenza virus infection in wild aquatic birds since 1961^ref.

• South Korea, which had never reported the disease previously : 19 000 birds out of 24 000 died of avian flu between 5 and 11 Dec 2003 at a farm in Yangsan, Eumsung district, Chungbuk province, about 300 km south of Seoul, and 5 000 that had not died from the disease were slaughtered; roughly 900 000 more chickens and ducks at around 30 farms within a 3 km (1.9 mile) radius of the farm would be killed. Since the virus first hit South Korea on 10 Dec 2003 (first official notification on 12 Dec 2003) cases have been reported at 19 farms nationwide and about 4.5 million chicken and ducks were culled of the country's total population of 108 million : affected farms have been quarantined but, after initial success, a further 88 000 birds were slaughtered in mid-January 2004 after a renewed outbreak. Ducks and other migratory birds were the most likely source of the H₅N₁ outbreak among poultry in South Korea : it first invaded ducks in the central city of Cheonan around October 2003. South Korea's livestock industry makes up around 0.4% of the country's gross domestic product. South Korea imported 88,283 tons of poultry between January and November last year : almost 40,000 tons came from Thailand. The outbreak has prompted South Korean consumers to stop eating poultry, and exports of chickens and chicken meat to Japan, Hong Kong, and China have been halted, dragging the chicken meat prices down by 40% to 611 won (USD 0.522)/kg after the outbreak was reported, but have jumped to 1.669 won (USD 1.426)/kg due to tight supplies, triggered by a mass poultry slaughter and import bans. Local feed production for poultry in January also dropped 11.5% from a year earlier to 288 407 tonnes. Test results showed that South Korea's bird flu gene types are identical with that found in Japan but are different from that found in Thailand, Vietnam, and Laos and accordingly causes of the cases are suspected to be different. On Feb 7 South Korea, began culling 291 242 chickens and ducks after 16 new bird flu outbreaks (8 duck farms, 7 chicken farms, and 1 chicken-and-duck mixed farm) were discovered :
• Chnonam Province, Naju city / 1
• Chungbuk Province, Eumsung district / 3
• Chungbuk Province, Jincheon district / 1
• Chungnam Province, Cheonan city / 5
• Chungnam Province, Asan city, south of Seoul / 1
• Kyongbuk Province, Kyongju city / 2
• Kyonggi Province, Icheon city / 1
• Kyongnam Province, Yangsan city / 1
• Ulsan Metropolitan, Ulju district / 1
Another case was reported on Mar 20 (the first new case since 5 Feb 2004) in 16 000 chickens (authorities are also recalling 1570 chickens that have already been distributed to a slaughterhouse south of Seoul) in a farm in Yangju, Kyonggi Province : 400 000 chickens and ducks at 20 farms within a 3-km (1.9-mile) radius of the affected farm would be destroyed and poultry farms within a radius of 30 km (19 miles) to 40 km (25 miles) would be checked twice a day by telephone for new outbreaks. Chicken deaths have been reported since 4 Mar 2004 in Yangiu but had been attributed to a liver disease. In a separate case, the ministry reported that 1 magpie (out of 99 captured and tested) was found to have died of the avian flu in the southern city of Yangsan, South Kyongsang Province, where an outbreak was reported in January 2004. But it was not expected to pose a significant threat, as the incubation period was short in magpies. The last case of the disease was confirmed on 21 Mar 2004^ref.
318 workers were injected with oseltamivir when they were engaging in the slaughter : on Feb 24, 2006, it was revealed that 4 workers, engaged in slaughter of poultry when bird flu was spreading in the country in 2004, have been asymptomatically infected with the H₅N₁ strain of bird flu after series of blood tests made by (South) Korea Center for Disease Control and Prevention (KCDC ) and the US CDC. The results prompted South Korean health officials to send samples to the CDC from another 2109 asymptomatic workers and of these, 5 were also infected, the health agency said on Fri 15 Sep 2006. The 5 did not develop major illnesses and have no strain to transmit bird flu^{ref1, ref2}
Moreover, the disease control authorities are conducting antibody tests on serum samples that have been collected from the 1,600 local people who contacted disease poultry in 2004. A total of 19 separate outbreaks affected 400,000 poultry at 392 poultry farms from December 2003 to March 2004, resulting in the culling of 5.28 million birds^ref. At the time, > 2,100 people who had helped with the destruction of the birds were tested for the virus with negative results. The virus responsible for the outbreaks in South Korea and Japan belongs to the V genotype of H₅N₁ avian influenza virus, whereas the predominant virus in East Asia belongs to the Z genotype. However, this is unlikely to be a relevant factor in human susceptibility to infection, since these genotypes are reassortants which differ only in the origin of their NA genome subunit. The more lethal, widespread H5N1 influenza virus (Z genotype) is less typical of previous pandemic influenza viruses, which infected millions but with an overall relatively low mortality of just a few percent or less, including the 1918 pandemic. Do we know whether this South Korean V genotype virus is more transmissible than the more lethal Z genotype or whether it is more or less likely to develop neuraminidase inhibitor resistance? Could it be that the more dramatically lethal Z genotype is attracting so much attention because of its higher mortality in humans but that, ironically, the quieter, less lethal V genotype is the more likely pandemic influenza virus candidate, if one believes that H₅N₁ influenza is likely to be the next pandemic influenza strain at all? Some researchers believe that a variant of the human influenza viruses (H₃N₂, H₁N₁, etc) already in existence are more likely to be the next pandemic influenza strain than a new zoonotic strain, which has to jump the species barrier and adapt to efficient infection and transmission between humans. If H₅N₁ was on the way to becoming the next pandemic influenza strain, I would be inclined to look for human cases like those in South Korea, whose mild or asymptomatic clinical picture may well indicate a successful adaptation to humans, suggesting the possibility of many humans having been infected but with only a small percentage of deaths -- that is, similar to the previous pandemic human influenza viruses.
Some 1000 out of 1200 ducklings died at a poultry farm in Dopyung-Dong, Jeju Island on 1 Nov 2004. About 10 died at the same farm on 21 Oct 2005 but tested negative for avian influenza.
• On Nov 23, 2006 South Korea reported a possible bird flu outbreak after 6,000 chickens on one farm in Seokmae village in the southern city of Iksan, Jeollabuk-do province, a major centre for the country's poultry industry 250 km (155 miles) south of Seoul, died in 3 days -- the first suspected cases since the country declared itself free of the disease in December 2005^{ref1, ref2}. The agriculture ministry ordered the culling of the remaining 6,000 birds on the farm. It sent an emergency supply of oseltamivir for 50 people and influenza vaccines for another 300. The ministry banned shipments to and from 6 farms within a 500-metre radius of the affected one. It said the area would be expanded if the bird flu virus is confirmed. > 200 poultry farms are within 10 km of the affected one, as is the country's top chicken meat processor Halim, which is supplied by them. Halim supplies 20 to 25% of the country's demand for chicken and also export cooked chicken to Japan and other countries^ref. Tests went positive on Sat Nov 25 2006^ref.
• The second case was reported on a farm in Hwangdeung district in North Cholla province, some 3 km southwest of the farm in Seokmae village where the virus was first discovered last week : some 200 of its 12,000 chickens died on Sun Nov 26 : < 170,000 chicken at several farms within a radius of 500 m from the site of the first infection had been slaughtered and buried on Nov 26-27^ref. By Thu Nov 30 the ministry plans to complete the culling of about 236,000 chickens and ducks as well as 300 pigs and 577 dogs^ref. The deaths of > 1000 chickens since Nov 20 in Seosan of South Choongcheong Province^ref was instead not related to H₅N₁ : the sick chickens were hatched from eggs distributed in mid-November from a breeding farm in Iksan, North Jeolla Province^ref. The farms lie on a path for migratory birds that are heading south from Russia, Mongolia and Kazakhstan and sparked concern that other parts of South Korea might have also been hit.
• a farmer was infected with an avian influenza virus at a farm in Gimje (257 km (160 miles) south of Seoul), North Jeolla Province in southwestern Korea but has been completely immunized, posing no threat of transmission. The farmer showed signs of a subclinical infection with no symptoms of bird flu and antibodies were already formed. He was immediately treated with oseltamivir and was taken to the hospital for examination. During the 10 days of the latent period of the influenza, the farmer showed no symptoms and has remained healthy until present. Moreover, the virus does not spread from body to body, so there is no need for citizens to be concerned at all. As no further patients have been discovered since Dec. 12, there is no possibility that any more people will be found infected with the deadly virus. The government has currently completed physical examinations on 26 people among 85 possible virus carriers. The examination results of the remainder will be released later on January 2006^{ref1, ref2}. The virus responsible for the outbreaks in South Korea (and also Japan) belongs to the V genotype of H5N1 avian influenza virus, whereas the predominant virus in East Asia belongs to the Z genotype. These genotypes are reassortants which differ in the origin of their NA genome subunit. This may be a determining factor in the apparent lack of virulence of the South Korean virus
• the 3rd case was discovered on 11 Dec 2006 at a quail farm in the same province about 170 km (100 miles) south from Seoul, some 18 km from the original outbreak^ref
• the 4th case emerged at a duck farm in Asan, South Chungcheong province, about 100 km further north^ref. According to the province, about 100 quarantine officials were dispatched early Sun 24 Dec 2006 to cull about 21 000 ducks, 2820 chickens and 4177 pigs from one pig farm located within a 500-meter radius of the outbreak site and 2000 chickens from one farm located about 3-km away^ref. Also, quarantine officials have collected 1000 samples of excrement from migratory birds near affected areas, including Chonsu Bay and Pungse Stream, to find out whether the virus is present in them. In addition, they have blocked the transportation of rice straw in farmlands located near the habitats of migratory birds in the region. Experts have been claiming that feeding rice straw to cows from farmlands near habitats of migratory birds should be blocked since the possibility that migratory birds could be the source of the bird flu has not been ruled out yet. 100 tons of rice straw from farmlands that are located near habitats of migratory birds such as Chonsu Bay, Sapkyo Lake, Sokmun Lake and Kumgang Bank have been supplied to farmlands nearby to be fed to their livestock on a daily basis until the government's move. The government has also banned the movement of chickens, ducks and eggs within a 10-km radius of the affected area. Can the South Korean decision to ban the feeding of cattle with rice straw that might have been contaminated by wild birds be explained by their concern over infecting domestic poultry that might cohabit the same or adjacent premises?
• the 5th outbreak occurred in Cheonan, about 60 miles south of Seoul on 20 Jan 2007. Authorities planned to start slaughtering 273 000 poultry within a 500-meter radius of the outbreak site and destroying eggs as early as Sat 20 Jan 2007 evening. The ministry also said it will make a decision on whether to kill another 386 000 poultry on Sun 21 Jan 2007 while limiting the movement of about 2.16 million chickens and ducks from 90 farms within a 6-mile radius of the outbreak^ref
• the 6th outbreak occurred at a farm at  Iljuk Village in Anseong city, 77 km (48 miles) southeast of the capital. The National Veterinary Research Quarantine Service confirmed the outbreak yesterday after the farm owner reported that chickens had begun laying fewer eggs and a number had died since Feb. 6 2007. The ministry ordered the culling of about 240,000 birds, including 133,000 chickens, at the farm and within a three kilometers radius. It also declared a 10-kilometer quarantine zone to control the movement of the poultry and eggs^ref
• the 7th outbreak occurred on 6 Mar 2007, when a farmer reported that about 30 ducks at the farm died of an unknown cause : quarantine authorities were to cordon off an area within a 3-km radius of the duck farm and destroy 55 000 chickens and ducks there^ref
• Vietnam, which has never reported the disease previously : to better understand the extent of transmission of avian influenza viruses (AIV) to humans in Asia, a cross-sectional virologic study was carried out in live bird markets (LBM) in Hanoi, Viet Nam, in October 2001. Specimens from 189 birds and 18 environmental samples were collected at 10 LBM. 4 influenza A viruses of the H₄N₆ (n = 1), H₅N₂ (n = 1), and H₉N₃ (n = 2) subtypes were isolated from healthy ducks for an isolation frequency of over 30% from this species. 2 H₅N₁ viruses were isolated from healthy geese. The hemagglutinin (HA) genes of these H₅N₁ viruses possessed multiple basic amino acid motifs at the cleavage site, were HP for experimentally infected chickens, and were thus characterized as HP AIV. These HA genes shared high amino acid identities with genes of other H₅N₁ viruses isolated in Asia during this period, but they were genetically distinct from those of H₅N₁ viruses isolated from poultry and humans in Viet Nam during the early 2004 outbreaks. These viruses were not highly virulent for experimentally infected ducks, mice, or ferrets. These results establish that HP H₅N₁ viruses with properties similar to viruses isolated in Hong Kong and mainland China circulated in Viet Nam as early as 2001, suggest a common source for H₅N₁ viruses circulating in these Asian countries, and provide a framework to better understand the recent widespread emergence of HP H₅N₁ viruses in Asia^ref. A very crude plotting of HPAI H₅N₁ outbreaks in a map of Indochina shows a nice progression of dates beginning in the mountains bordering Thailand and Laos and following the Mekong and Mae Nam Chao Phraya waterways. There does seem to be a nidus in the mountains, but my personal bias (pirate ancestors!) leads me to wonder whether there is a handy mountain pass at 100°E and 20°N through which poultry might be smuggled. The problem began at  the end of October 2003 and Vietnamese authorities became more concerned after 70,000 chickens abruptly died on farms in the southern provinces of Long An and Tien Giang provinces in southern Vietnam, > 700 miles from Hanoi (Ho Chi Minh city). The Vietnamese government decided to kill all chickens in a 3-km range around epidemic areas and has banned  movement of all chickens within a 10-km range of the epidemic areas. To date, the virus has been reported from 2570 communes in 57 of the country's 64 provinces, with outbreaks in 445 separate locations : since 23 Dec 2003 (but first official notification on 9 Jan 2004 !), 38.1 million poultry stock of the Vietnam's > 200 million (15%; not a major exporter) have either died or been destroyed because of the disease (Hanoi has culled some 500,000 chickens).
• Location / No. of outbreaks
• An Giang / 143
• Bac Lieu / 21
• Ben Tre / 60
• Bình Dinh / 14
• Bình Duong / 19
• Ca Mau / 28
• Can Tho / 17
• Cao Bang / 1
• Da Nang / 23
• Dac Lac / 27
• Dien Bien / 8
• Dong Nai / 4
• Dong Thap / 73
• Ha Nam / 62
• Ha Tay / 51
• Hai Duong / 65
• Hung Yen / 22
• Kien Giang / 8
• Lai Chau / 17
• Lam Dong / 8
• Long An / 152
• Phu Tho / 57
• Quang Nam / 22
• Quang Ngai / 3
• Soc Trang / 24
• Son La / 13
• T. Thien Hue / 14
• Tay Ninh / 22
• Thai Nguyen / 27
• Thanh Hoa / 42
• Tien Giang / 91
• Tong so / 35
• Tra Vinh / 10
• Vinh Long / 42
• Vinh Phuc / 33
• Yen Bai / 24

Total 1282
No new outbreak was reported in poultry since 26 Feb 2004. An isolated outbreak of H₅N_non-1 was found at the end of April 2004 on a farm in Mekong, Cao Lanh township, in the province of Dong Thap (Mekong Delta rea, south Viet Nam, bordering Cambodia on the north), and was successfully contained. An analysis of 10,000 samples from throughout Viet Nam showed lots of these samples were positive for H₅N_? virus. Reports indicate that pigs have also been infected : preliminary tests found the bird flu virus in the nasal swabs of pigs and ducks in Hanoi. The price of already more expensive animal protein sources (e.g. fish) rose by a further 20-30%, placing them well beyond the reach of many of the poorer consumers. The H₅N₁ outbreak in humans in Vietnam apparently began in October 2003, when children from several villages near Hanoi in southern Vietnam began falling ill with severe respiratory infections. 5 Jan 2004: Health authorities in Viet Nam inform the WHO office in Hanoi of an outbreak of severe respiratory illness in 11 previously healthy children hospitalized in Bach Mai Hospital, the state-run infectious diseases center in Hanoi, with the most recent hospital admission on 4 Jan 2004. 7 cases were fatal and 2 patients remain critically ill. A 12th case, a sibling of one of the Hanoi cases, died of a respiratory illness in  provincial hospital. Included in this report are 6 children, aged 9 months to 12 years, who died in a Hanoi hospital of respiratory illness of unidentified cause between 31 Oct and 30 Dec 2003. For the first 5 cases, no samples are available for analysis. Samples are available for the 6th case, a 12-year-old girl who was admitted to hospital on 27 Dec and died 3 days later. All of these cases were identified retrospectively based on hospital records. 11 Jan 2004: Since the 5 Jan report, Vietnamese officials have identified 2 further cases of severe respiratory illness (another child and the first adult), bringing the total since the end of October 2003 in Hanoi's hospitals to 13. Tests on samples from 2 fatal cases in Viet Nam (12 year old girl and 10 year old boy), performed by Hong Kong's National Influenza Centre, confirm infection with the H₅N₁ AI virus strain. 27 patients have been laboratory confirmed to have been infected with H₅N₁, and among them 20 have died:
• 7 children, including 5 in Hanoi
• 5 from the south of the country : an 8-year-old girl remains hospitalized in Ho Chi Minh City.
• in the south of the country
• a 4-year-old boy who fell ill on 22 Dec 2003, was hospitalized in Hanoi on 29 Dec 2003, has fully recovered and been discharged from hospital
• a 8-year-old girl from Ha Tay province hospitalized since 15 Jan who died on Sat 17 Jan 2004
• a 13-year-old boy from Hanoi admitted to the Paediatric Hospital No. 2 on 19 Jan with respiratory ailments but immediately transferred to Hanoi hospital for treatment, died on Thu 22 Jan 204.
• a 30-year-old woman, mother of a diseases child
• a man was hospitalized in Hanoi with a severe respiratory illness on 7 Jan and died on 12 Jan, while the wife has fully recovered.
• his 2 sisters, aged 23 and 30 in Thai Binh province, 110 km (70 miles) southeast of Hanoi, were admitted to hospital on 13 Jan 2004 and died on 23 Jan. Laboratory tests received over the weekend have confirmed AI A (H₅N₁) virus infection in the sisters : their viruses have been fully sequenced and contain no human influenza genes. However, this is not definitive proof that person-to-person transmission has not occurred : the results of analysis of the structure of the HA protein of the 1918 pandemic influenza virus led to the conclusion that mutation alone is sufficient to explain the acquisition of human transmissibility. Neither the man nor his wife was tested. WHO considers that limited human-to-human transmission, from the brother to his sisters, is one possible explanation.
The family members gathered in late December 2003 to prepare for the man's wedding on 3 Jan 2004. Both the man and one sister are reported to have handled ducks while preparing a meal on 4 Jan. However, the investigation failed to reveal any direct contact with poultry for the man's other sister and his wife. In the absence of evidence of direct exposure to poultry in these 2 cases, WHO epidemiologists are considering various alternative explanations. Both sisters are known to have provided health care for their brother prior to his hospitalization, and would thus have had opportunities for close exposure. Direct human-to-human transmission following this close exposure is thus one possible explanation. However, contact with an infected bird, or some other environmental source of the virus, is another possible route of infection that has not been ruled out. Outbreaks of H₅N₁ in poultry are widespread in Viet Nam. Local authorities report that no other family members or wedding guests developed an illness. No illness has been detected in members of the community where the wedding was held, or in health staff involved in care of these cases. Le Thi Sang lost her 3 children after the family served 66 pounds of chicken at her son's wedding. Her 2 daughters tested positive for bird flu, while her son died of similar symptoms. Despite her loss, Sang still buys poultry a couple times a week and insists her children were not infected with AI. "My son and daughter died of pneumonia, while the other daughter died of stomach [bleeding]," said Sang, 58, on Feb 2005. "It's not bird flu."
• a 17-year-old woman died on Tue 27 Jan 2004
• a 19-year-old man who has recovered
• a 20-year-old woman who remains
• a 18-year-old man who died on 2 Feb 2004 at a hospital in Ho Chi Minh City. He is the country's first confirmed case from the Central Highlands area.
• a 16-year-old woman from Soc Trang province died on Tue 3 Feb 2004
• a 6-years-old girl died in Ho Chi Minh City on 3 Feb 2004
• a 24-year-old man died in Ho Chi Minh City on 3 Feb 2004
• a 27 year old man from southern Binh Phuoc province and believed to have caught the disease at his family's chicken farm died on Feb 9 2004
• a 23 year old man from central Lam Dong province is in hospital in Ho Chi Minh City in a stable condition
• a 19 year old man who had been hospitalized in Ho Chi Minh City died on Feb 12 204
• a young man from Ho Chi Minh City (16 Feb 2004)
• a 15-year-old boy was admitted to hospital on 9 Feb 2004 (confirmed on Feb 17) with fever, coughing, and shortness of breath in northern Thanh Hoa province. The boy's family raises no poultry, and says he did not come in contact with birds, although his neighborhood did experience a bird flu outbreak
• a 3-year-old boy from Lam Dong Province died on Feb 18
• a 16-month-old baby girl from Dong Nai Province hospitalized since Mon 16 Feb 2004 in Ho Chi Minh City remains in stable condition.
• a 12-year-old boy from southern province of Tay Ninh, an ethnic Cham minority, was admitted to a hospital in Tay Ninh province, 60 miles northwest of Ho Chi Minh City, on March 13 suffering from diarrhea and high fever, developed a serious lung infection and died 2 days later. The boy's family had eaten their sick chickens about 5 days before the boy came down with the illness on March 10
After a review of laboratory information held on cases of influenza A/H₅ by the Ministry of Health of Vietnam and the WHO Country Office Vietnam, 1 case has been reclassified from confirmed to probable. This individual had a high titre for H₅ antibodies on sera collected 15 days after onset using the microneutralization test. 271 suspected cases from 36 cities and provinces : 38 have died, 107 remained hospitalized, and 126 recovered. The discordance of the locations of the human fatalities, predominantly among unrelated individuals in the north and the epicentre of the avian disease in the south, is consistent with the assertion that as yet there has been no significant human-to-human transmission of disease. However, the route of transmission of the avian virus to humans has yet to be established. Curiously, one of the 2 suspected human cases in the south has been reported from a province considered to be free of avian disease at present. No reports indicate that health care workers have been infected. All genes are of avian origin, indicating that the virus had not yet acquired mammalian  genes. On 30 March 2004, after 1 month of no new recorded outbreaks of the virus, Viet Nam declared an end to its bird flu crisis that had killed 17% of its poultry population and claimed 16 human lives since its previous outbreak in December 2003. A total of 43.2 million fowl nationwide either died or were culled, causing direct losses of 1.3 trillion Vietnamese dong (USD 82.8 million) to the local poultry industry.
The second wave : since June 29, 2004, AI was reported on 31 farms, in 22 districts, in the 11 provinces of the Mekong Delta: Dong Thap, Vinh Long, Can Tho, Tien Giang, Bac Lieu, Hau Giang, Ba Ria Vung Tau, Tra Vinh, Ben Tre, Kien Giang, and Long An. The results from samples taken from infected fowl in the south confirmed the presence of the H₅N₁ strain. The suspected AI outbreak in the northern Bac Ninh Province was confirmed as fowl cholera (avian pasteurellosis). Another AI outbreak was reported in southern Can Tho city on 3 Aug 2004. All 600 affected chickens on farms in the city's Phong Dien District were culled. As of 29 Jul 2004, the number of fowl affected by AI in Viet Nam was estimated at 63 000 (45 000 chickens, 13 000 ducks, and 15 000 quail) on 30 small-scale farms. By 3 Aug 2004, Viet Nam recognized that 7 provinces -- which had been dealing with recurrences of AI -- had already met the conditions to declare themselves free of the disease, while still maintaining surveillance measures. However, the flood-stricken provinces of Ha Giang, Cao Bang, Thai Binh, Ha Tay, Hai Duong, Phu Tho, Ninh Binh, Hoa Binh, Lao Cai, and Hai Phong City, where poultry movements are expected to occur, should require heightened vigilance, since the risk of AI re-introduction is high. The most recently reported mortalities in birds involved approximately 3400 quails in the province of Hau Giang on 02 Aug 2004. Some 17 000 chickens and other birds have been culled in Hau Giang province in July. The virus has wiped out 17% of the country's fowl population, totaling 43.2 million poultry across 57 of 64 localities, causing losses of VND 1.3 trillion (USD 83.3 million) between late 2003 and March 2004. It killed a further 21 173 chickens, and 1153 ducks and geese, in 18 poultry farming bases, in 8 southern provinces, during the 2nd outbreak in early July 2004. Vietnam declared earlier in October 2004 that it had brought under control its latest outbreaks of AI, which has killed at least 19 people in the communist nation since late 2003. Diplomats, however, questioned whether the timing of the announcement was linked to the influx of European and Asian leaders for the 8-9 Oct 2004 Asia-Europe Meeting (ASEM) in Hanoi. Between 4 Oct and 16 Oct 2004, the country discovered 2000 sick poultry in Long An province, nearly 1000 in Soc Trang province, 150 in Tien Giang province, and a small number of fowl in Ben Tre province. > 44 million poultry have also died or been culled, with over 60 000 of the deaths coming after the government's controversial 30 Mar 2004 declaration that HPAI had been eradicated. Since the end of June to Nov 18, AI has been confirmed in 14 provinces, and 46 984 birds have died or been culled. The case in chickens in Soc Trang Province on 1 Oct 2004 was confirmed to be AI H₅ (no N type reported to date). The most recent confirmed H₅ infection was reported on 11 Oct 2004 in a chicken farm in Tan My Chanh, My Tho Provincial City, Tien Giang Province with 1200 deaths out of total 3000 chickens. A new case was suspected in mid-November in Can Tho City, Binh Thuy District in 20 chickens raised by a household, the flock has been culled. 20 chickens raised by a household in Binh Thuy district in the southern city of Can Tho were found to have been affected by H5 in mid-November, all of them were already killed, local newspaper Liberation Saigon on Thursday [18 Nov 2004] quoted the country's Department of Animal Health as saying.
Since August 2004, Viet Nam has detected 4 human cases :
• 4 suspected victims all from the southern Mekong Delta province of Hau Giang, around 106 miles (170 km) southwest of Ho Chi Minh City (3 of the 4 suspected victims were from the same family, and included at least one high school student) died between 30 Jul and 2 Aug 2004
• deaths of 5 children aged between 14 months and 4 years, from the beginning of August 2004 to Thu 9 Sep 2004
• at least 8 patients, 3 of whom have died, have been treated in hospital on suspicion of having AI. Samples from the 3 fatal cases have been identified as H₅ serotype virus, and a sample from one of the 3 has been identified as H₅N₁ serotype virus. It is likely, therefore, that these patients have contracted AI A (H₅N₁) virus, but the nature and location of their exposure is still unclear. Person-to-person transmission appears to have been excluded
• a 4-year-old boy died on 2 Aug and an 11-month-old girl died on 4 August in the northern Ha Tay province, 20 kilometers west of Hanoi.
• a 27 month-old baby boy from Long My (the district of Hau Giang province where one person was confirmed to have died of laboratory confirmed H₅N₁ infection on 2 Aug, and where 3 others died of suspected bird flu but were not tested for the disease) was admitted to the hospital, on Sat 14 Aug, after 2 days of displaying a high fever after he had eaten duck raised by his family from an animal that had died mysteriously (AI virus should be inactivated by normal methods of cooking, therefore, transmission of the virus must have occurred prior to cooking)
• a 14-month-old baby boy who was hospitalised in Hanoi on 28 Aug 2004 and then transferred to the Central Paediatric Hospital for specialist care, died on Sun 5 Sep and was confirmed to have died of H₅N₁ infection
• a 25-year-old woman died on 6 August in Hau Giang province
• a 69-year-old man who returned after a 15 day vacation visit to Viet Nam and Cambodia was hospitalised in isolation in the intensive care unit at the Central University Hospital in Nancy, Alsace, northeastern France with symptoms suggestive of AI virus infection on Thu 2 Dec 2004, but blood and tissue samples sent to the Pasteur Institute in Paris tested negative for AI A(H₅N₁) virus
• a 16-year-old girl from the southern Mekong Delta province of Dong Thap, which had slaughtered a chicken she brought with her from Dong Thap province to southern Tay Ninh province, where she was visiting her uncle, developed the disease's typical symptoms of high fever, coughing and breathing difficulties on 19 Dec 2004, was admitted to a clinic in Tay Ninh province on Dec 24, before being transferred to the Hospital for Tropical Diseases in Ho Chi Minh City on 26 Dec, where she died on Sat 8 Jan 2005 after spending 2 weeks breathing with a respirator. Tests confirmed AI A(H₅N₁) virus. None of her uncle's 8 family members developed AI symptoms, and the man's house was disinfected
• a 6-year-old boy from the southern province of Dong Thap died on 30 Dec 2004
• a 9-year-old boy from Cang Long district, of the southern Mekong Delta province of Tra Vinh (one of the 8 provinces which reported the recurrence of bird flu) was admitted at the provincial clinic, then transferred to the Hospital for Tropical Diseases in Ho Chi Minh City on Tue 4 Jan 2005 together with a 14-year-old body, and died the same day. Tests confirmed AI A(H₅N₁) virus. He did not eat chicken but had been infected when he swam in a channel where residents disposed of bird flu infected poultry^ref
• a 18-year-old girl from Tien Giang province (in an area where there are bird flu-infected fowl) developed symptoms on 1 Jan 2005, was hospitalized on Jan 5 and died on Jan 19
• her 15 year old sister is an additional suspected case
• a 18 year-old woman from Hau Giang province in the Mekong Delta, who was a suspected AI case, was admitted to hospital on 1 Jan 2005 and died on Mon 10 Jan 2005
• a 35 year-old woman from Viet Nam's southern province Tra Vinh (in an AI affected area) was admitted to hospital on 9 Jan, transferred to Hospital of Tropical Diseases in Ho Chi Minh City on Tue 11 Jan 2005 with symptoms of high fever and lung infection, 14 days after she killed and ate a diseased chicken (she was hired by a neighbour to bury dead ducks and pluck sick ducks' feathers for sale 4 days before she developed fever), and died on Jan 12
• a 46 -year-old man resident in Thai Binh province, developed symptoms on 26 Dec 2004, was admitted to hospital in Hanoi and subsequently died of pneumonia on 9 Jan : after 2 initial negative tests, a 3rd postmortem test resulted positive for AI.
• his 42-year-old brother (Nguyen Thanh Hung) resident in Hanoi, who had provided bedside care for his brother, developed symptoms on 10 Jan 2005, 9 days after his brother fell ill, and was admitted to the same hospital in Hanoi on 12 Jan with symptoms of high temperature and damaged lungs. After an initial negative test, 2 following tests resulted positive for AI, making it the 1st case of the deadly disease in the capital and the north of the country. Since admission to the institute the patient has felt better and is set to be discharged from the Tropical Disease Institute on Fri 28 Jan. The patient has not had contact with fowl and does not live in an AI hit area.
• his 36-year-old brother from Viet Nam's northern Thai Binh province received medical checkups at the institute in the 3rd week of January 2005, tested positive for AI A (H₅N₁) virus and is receiving treatment at the Tropical Disease Institute in Hanoi
The investigation surrounding the 3 brothers is considering 2 hypotheses :
• the 1st hypothesis includes the possibility that the 42-year-old man may have acquired his infection directly from his brother. All evidence to date suggests that isolated instances of limited, unsustained, human-to-human transmission can be expected from AI viruses. Their occurrence does not call for any change in the present level of pandemic alert. Intensified surveillance for respiratory symptoms in close contacts of the 2 men has been initiated in both Tai Binh Province and Hanoi, and it is reassuring that no cases of respiratory illness have so far been detected among these people. Health authorities in Viet Nam have launched an immediate investigation of the source of infection in the 2 brothers. WHO staff in that country are being kept closely informed. Up to the present there has been only a single instance of possible person-to-person transmission, and that was in Thailand in September 2004
• the 2nd hypothesis is focusing on a possible direct source of poultry-to-human transmission. Preliminary findings point to a family meal in which a dish containing raw duck blood and raw organs (a Vietnamese delicacy) was served at a local market on 29 Dec 2004. Public health officials in Viet Nam have repeatedly advised against the consumption of dishes made with fresh duck blood or with raw or inadequately cooked poultry products. As a precautionary measure, similar culinary practices involving dishes containing raw poultry parts or organs should be avoided in all countries experiencing outbreaks of H₅N₁ HPAI in poultry. To date, most human cases linked to contact with poultry are thought to have acquired their infection following exposure to dead or diseased birds around households. Evidence suggests that particularly risky exposure occurs during the slaughter, defeathering, and preparation of poultry for cooking. Proper cooking destroys the H₅N₁ virus. In general, WHO recommends that poultry should be cooked until all parts reach an internal temperature of 70°C. No cases of H₅N₁ infection have been linked to the consumption of thoroughly cooked poultry and egg products. Media reports that a 3rd 35-year-old brother has been hospitalized have not been confirmed
The timings of the apparent infection of 2 of the 3 brothers favored person-to-person transmission of infection rather than contraction of infection from a common food source.
• a 17-year-old boy from Phuoc Long district in the southern province of Bac Lieu was admitted to hospital on 10 Jan 2005 and died on 14 Jan : samples tested positive for AI on 25 Jan. The boy slaughtered a chicken before showing symptoms
• a 35-year-old woman from the southern Mekong Delta province Dong Thap developed symptoms on 14 Jan, was admitted to the Hospital for Tropical Diseases in Ho Chi Minh City on 20 Jan and died on 21 Jan. She tested positive for the H₅N₁ serotype of AI virus. The woman developed a high fever a week after slaughtering a duck together with ther daughter : the woman did not eat the duck. The woman might also have been infected by stork droppings in her lotus pond where she often worked. She did not slaughter or eat sick or dead chickens, but she often had a bath in a canal which contained dead fowl, her relatives said.
• her 13-year-old daughter from Dong Thap province developed symptoms on 20 Jan 2005, was hospitalized on 22 Jan, tested positive for the H₅N₁ serotype of AI virus and died on Jan 28 at Pediatric Hospital No. 1 in Ho Chi Minh City. In view of the 6-day interval between dates of symptom onset in the mother and her child, limited human-to-human transmission, as seen during similar events in the past, cannot be ruled out at this stage.
• a 10-year-old girl from Long An province developed symptoms on 13 Jan 2005, was hospitalized on 20 Jan, tested positive for the H₅N₁ serotype of AI virus and died at 20:00 on Jan. 30 at Pediatric Hospital No. 1 in Ho Chi Minh City. The girl developed a high fever and bad cough a week after helping her family bury some dead chickens.
• a 66-year-old man from Hanoi city was admitted to hospital on 25 Jan 2005, is now being treated at a Hanoi hospital with confirmed H₅N₁ serotype of AI virus and will be discharged in the Feb 8 week
• a 30-year-old man (Han Ngoc Manh) from Hung Yen province had contact with sick fowl, was hospitalized on 22 Jan 2005 and is now being treated at a Hanoi hospital with confirmed H₅N₁ serotype of AI virus : he was discharged in the Feb 8 week (31 Jan?)
• a 30-year-old man from Phu Tho province had contact with sick fowl, was hospitalized on 23 Jan 2005 and is now being treated at a Hanoi hospital with confirmed H₅N₁ serotype of AI virus (?)
• a 32-year-old man from the province of Phu Tho, 80 km (50 miles) northeast of the capital Hanoi, developed a high fever, coughing, and breathing difficulties on 12 Jan 2005, and died on Thu 27 Jan 2005 after spending 5 days in Bach Mai Hospital in Hanoi. The man's family raised poultry but none of them has shown signs of illness : there were no avian influenza outbreaks reported among poultry in his village. However the man was involved in the trade of poultry from infected areas 6 months ago but had stopped since then
• a 39-year-old man from central Quang Nam province died on Jan 30 in a hospital in central Da Nang city. If confirmed, he would the 1st casualty of the virus in central Viet Nam.
• a 24-year-old man from Hanoi was admitted to the city's Bach Mai hospital Jan. 25 with a high fever and cough before testing positivefor the H₅N₁ strain of the virus. The man had been removed from a respirator and was recovering
• a 4-year-old boy in southern Vietnam presented with severe diarrhea, followed by seizures, coma, and death. The CSF contained 1 WBC/mm³, normal glucose levels, and increased levels of protein (8.1 g/dl). The diagnosis of avian influenza A (H₅N₁) was confirmed by isolation of the virus from cerebrospinal fluid, fecal, throat, and serum specimens
• the patient's 9-year-old sister had died from a similar syndrome 2 weeks earlier
In both siblings, the clinical diagnosis was acute encephalitis. Neither patient had respiratory symptoms at presentation. These cases suggest that the spectrum of influenza H₅N₁ is wider than previously thought^ref. Continuing doubts about the sensitivity of the diagnostic test performed in different laboratories makes many of these statements difficult to interpret, and much is being concluded from a few cases. For example, it has been widely reported that encephalitis may be associated with avian influenza A (H₅N₁) virus infection, whereas 100 encephalitis cases examined subsequently were found to be H₅N₁ virus-negative. Convincing seroprevalence data are still lacking
• up to 10 additional suspected human cases are under investigation another patient died on Thu 13 Jan 2005 in Mekong Delta province :
• a 48-year-old man, his younger brother (suspected case of transmission of infection from person to person ?) and a 62-year-old man were hospitalized on Sat 15 Jan 2005 with acute pneumonia, which doctors in Hanoi suspected could be caused by AI virus, the Quan Doi Nhan Dan daily reported on Mon 17 Jan 2005. The 48-year-old man died, and the other 2 patients were in critical condition. If the cause of the man's death is confirmed as bird flu, it would be the 1st fatality in the north of the country, but a physician from Hanoi's Clinical Institute for Tropical Disease denied that the 48-year-old man had AI
• a 14-year-old boy, was taken to a Ho Chi Minh hospital with high fever and coughing on Sun 16 Jan 2005 from the southern province of Tra Vinh
• a 10-year-old child from northern Ha Tay province admitted on 20 Jan the Hanoi-based National Hospital of Pediatrics is suspected to have contracted H₅N₁
• 2 local people, a 15-year-old teenager from southern Kien Giang province and a 24-year-old woman from central Binh Dinh province, have just been admitted to provincial hospitals after showing symptoms of high

temperature, cough, and damaged lungs. The patients are suspected to have contracted H₅N₁, since they either ate chicken or traded poultry.
• 6 other children suspected of avian infections are being treated at Nhi Dong 1 (Children 1) hospital in the city
On Jan. 29-30, 7 people from Vietnam's northern region were admitted to the Tropical Disease Institute in Hanoi capital with symptoms of bird flu infections : the tests have proved negative so far. 8 people from Viet Nam's northern region have been hospitalised with AI symptoms on Thu 3 Feb 2005, raising the total number of confirmed and suspected cases under treatment there to 21. Of the patients, 3 have been confirmed to have contracted AI A (H₅N₁) virus infection.
• 5 cases from Thai Binh province, 110 km (70 miles) southeast of Hanoi and far from the southern Mekong Delta where the outbreaks began in December.
• a 21-year-old man (Nguyen Sy Tuan) from Thai Thuy district developed symptoms on 14 Feb 2005, was admitted to the hospital on 20 Feb, was transferred to the Tropical Disease Institute in Hanoi on 22 Feb after exhibiting a high temperature and tested positive on Feb 25. Tuan left his home among the glistening paddies of northern Vietnam's rice-growing region more than a year ago for Haiphong, on the coast, where he worked harvesting seaweed for use in local cuisine. In early February, he returned to his family's simple brick house to celebrate the Tet New Year holiday. Tuan slaughtered a chicken (goose ?) for a Lunar New Year meal early in Feb, cutting its neck while his 14-year-old sister clutched the wings and legs. The bird was likely infected, and soon the siblings were, too. He ate raw goose blood before exhibiting bird flu symptoms. After 10 days, with his breathing failing, the doctors intubated and put him on a ventilator. The infection spread to his kidneys and liver. On Apr 2005 the young man has begun to eat rice again and can finally breathe without a mechanical ventilator : he left the hospital on May 13
• his 14-year-old sister (Nguyen Thi Ngoan) developed symptoms on 21 Feb 2005 and was hospitalized at Hanoi the following day, where she laid in the cot beside her brother and her temperature soared to 105°F. She was under treatment at the Thai Binh Hospital. After initial negative tests, she tested positive on Feb 27. But the fever broke after 4 days and returned to normal within 2 weeks : Ngoan went back to school in late March as a local celebrity, teased by her peers as "Miss H5." As for her brother, she had eaten chicken at a friend's house during Lunar New Year festivities earlier in Feb, too. The family did not raise any poultry, but there were bird flu outbreaks in their neighbourhood.
• their 80 (81 ?)-year-old grandfather despite asymptomatic tested positive on Mar 9 with the H₅N₁ avian influenza virus. The man remains in good health at his home without any of the disease's typical symptoms of high fever and breathing difficulties. None of the remaining 12 family members have tested positive for the virus. The grandfather has been given anti-viral drugs and asked to limit his contact with other people. The man's family had raised chickens, one of which died during Tet. The man then gave the 3 remaining chickens to his daughter, the mother of the 21-year-old man and his 14-year-old sister. He drank raw duck blood during the Tet
• a 26-year-old male nurse (Nguyen Duc Tinh) from Thai Thuy district's Healthcare Center in Thai Binh province who tended the 21-year-old man from Thai Binh with bird flu was admitted to the institute on Feb. 28 with symptoms of high temperature, coughing and breathing difficulty, and tested positive on Mar 7. No members in his family have showed symptoms of bird flu. But just 2 weeks after joining Tuan in the Hanoi hospital, Tinh was discharged and went back to his village.
• a second 41-years old female nurse who cared for the 21-year-old man was admitted to Hanoi's Bach Mai Hospital on Thu 10 Mar 2005 with a high fever, coughing and a lung infection and remains in critical condition : she tested negative on Mar 14. Health authorities are closely monitoring the health of 2 doctors and 2 other nurses at the center who had contact with the 21-year-old man. None of them have shown any symptoms
• a 36-year-old man (Nguyen Thanh Chung) from Vu Van Commune in the Vu Thu district contracted bird flu after coming into contact with infected poultry, was admitted to the Tropical Disease Institute in Hanoi on Feb 22, tested positive on Feb 26, but negative on the 2nd examination.
• a 69-year-old man was taken to a hospital in the northern province of Thai Binh developed symptoms on 19 Feb, was admitted to the hospital the same day, and died on 23 Feb 2005. He tested positive on Feb 27. The man had eaten chicken with his family during the Lunar New Year
• her 68 (61?) -year-old widow tested positive on Wed 9 Mar 2005 despite being completely healthy. She took care of her husband when he was sick. Other than that, she said she ate only pork, and all 4 chickens raised in her house tested negative for avian influenza. She had slaughtered a chicken for a meal on the 3rd day of the Lunar New Year Festival (early February 2005). The woman, in good health in her home town, received treatment with oseltamivir
• a veterinarian woman was admitted to the Institute of Tropical Diseases in Hanoi city on Wed 9 Mar 2005. She has frequently had contact with poultry, including infected fowl.
• a man died on Mar 13 in the southern province of Kien Giang, 3 days after he was transferred from the Chau Thanh district health center, where he had been on a respirator,
• a 35-year-old woman from a Hanoi district who works as a rubbish collector in the city and has frequently been present in live poultry markets, developed symptoms on 18 Feb 2005, was hospitalized on 24 Feb 2005, and tests confirmed on Mon 28 Feb 2005 that she had contracted avian influenza virus
• from Chau Hoa commune of the central Quang Binh province : 195 patients showing symptoms (?)
• Tuyen Hoa district :
• in late February 2005, a family, who live in an area hit by bird flu in early February, slaughtered a chicken given by one of their relatives for meal, and several days later, the family's 3 children suffered a sudden illness (the sister came down with a fever only 2 days later)
• a 13-years older female baby was hospitalized with a high fever died in Quang Binh hospital from AI infection on 9 Mar 2005 : she was immediately buried by her family and diagnostic samples were not taken
• her 5-years old brother was admitted to hospital on 12 Mar and transferred to Hue Central Hospital on Tue 15 Mar 2005 with typical bird flu symptoms: high fever, coughing, and respiratory problems. He tested positive on Mar 17 is being treated in an isolation ward with respiratory support equipment, but is recovering
• her aunt who cared for her is being closely monitored in her residential area since she has a light fever and breathing difficulty
• apparently a younger sister was left unscathed
• a 41-year-old man was admitted to a hospital in Hue central city on Mon 21 Mar 2005, after having a high fever for a week
• a 16-month-old boy was hospitalized in Hue central city on Tue 22 Mar 2005 on suspicion of having contracted avian influenza A. His parents said he had fever. But he does not have any fever anymore, and we don't see any symptoms of avian influenza
It is not yet clear whether these people, some of whom had reportedly eaten sick chickens, have the symptoms of the deadly bird flu or normal influenza. Of the 195 patients showing symptoms, 108 are from Kinh Chau village, while the rest live in other villages in Chau Hoa commune. The outbreak hit the province's Kinh Chau village in Chau Hoa commune just ahead of the Lunar New Year holidays, which started on 9 Feb 2005. The province is currently trying to stop the spread of the influenza by culling all poultry in the commune.
• Quang Trach district : on 17 Mar 2005, a person was admitted to a hospital in the district with the bird flu symptoms of fever and breathing difficulty.
The (200-people) figure seems to be very exaggerated : a team from the provincial health department sent to the commune on Sat 19 Mar 2005 discovered very few sick people so far after examining 7 families. When local health officials made an inspection, they found that 300 out of 500 chickens raised in the locality had died. In another development, the Market Watch Team of northern border Lang Son Province seized > 1.6 tons of chickens illegally imported through local border gates. All seized chickens, which were not quarantined, have been culled. The 1st avian influenza tests carried out on both sick patients and residents without symptoms were all negative on Mar 24
• a ? from Hai Duong province and the other from Nam Dinh province, were admitted to the Tropical Disease Institute in Hanoi on Tue 1 Mar 2005
• from northern Quang Ninh province, which borders China :
• a 40-year-old woman developed symptoms on March 13 and was transferred in stable condition to Hanoi's Bach Mai Hospital on March 17. She and her family ate chicken on March 10 and she began developing the disease's typical symptoms of fever, coughing and laboured breathing 4 days later and tested positive on Mar 25
• a 34-year-old doctor who worked at the Viet Nam-Sweden hospital in Uong Bi fell sick at work on Fri 1 Apr 2005, his breathing worsened quickly despite emergency treatment for SARS, and died on Sun 3 Apr 2005
• a 21-year-old woman, used to work at a hairdressers's shop, hospitalized in early March with fever and coughing tested positive for both avian influenza A (H₅N₁) virus and HIV-1 on Apr 14 2005. Quang Ninh province bordering China has one of the highest number of HIV carriers in Viet Nam, most of them drug addicts and prostitutes. The fate of the patient experiencing HIV and AI virus co-infection may give an initial indication of any effect of HIV status on susceptibility to avian influenza virus infection. The HIV patient -- though weak -- appears to be resisting AI virus infection better than some of those not known to be HIV carriers, and hopefully the outcome will show that an HIV/AIDS status does not predispose individuals to greatly enhanced risk
• a 17-year-old girl from Nam Dinh province (90 km (56 miles) south of Hanoi), was hospitalised in stable condition at Hanoi's Bach Mai Hospital on ? Mar, died on 23 Mar and tested positive on Mar 25. There had been no outbreaks among poultry in her village
• from the northern port city of Hai Phong :
• 5 members of one family from Kien Thuy rural district were admitted to the city-based Viet- Tiep Hospital on March 22 2005 with coughing and breathing difficulties : they all tested positive on Mar 28 and are now in stable health condition.
• a 39 (35?)-year-old man (Vu Van Son)
• his 33-years-old wife
• 3 daughters aged 4 months old, 3 (13?) years old and 10 years old
Before exhibiting bird flu symptoms, they ate sick chicken raised by themselves. The family, who live in a bird flu-hit area, have their flock of nearly 200 chickens recently culled by local veterinarians. Earlier, over 200 chickens of the flock died. Several days after admitting the 5 patients, the hospital received 2 suspected cases of bird flu infections:
• a 41-year-old woman neighbor of the family was hospitalized on suspicion of having contracted avian influenza A (H₅N₁) on 25 Mar 2005 after suffering cough and breathing difficulty
• a child
All the 7 patients live in the same commune.
• a 12-year-old girl, who lives near a poultry slaughterhouse, was in an isolation ward on Mon 4 Apr 2005 in the northern city of Haiphong
• a 30-year-old patient (Cao Lu Uy) from the neighboring province of Quang Tri was hospitalized on 23 Mar 2005 at the Hue Central Hospital in central Hue city. The patient has not had contact with sick poultry. 20% of total waterfowl flocks in Vietnam's central Quang Tri province was been found to contract bird flu virus strain H₅N₁ on 24 Jun 2005. The provincial Veterinarian Bureau culled over 23 000 waterfowl, mainly ducks, in the 38 infected flocks. It will further the culling if the 144 untested flocks prove to be infected with H₅N₁.
• a 25-year-old woman was taken to Ho Chi Minh City's Hospital for Tropical Diseases on Tue 29 Mar 2005 with coughing and fever after returning from Cambodia
• a 27-year-old Vietnamese woman who drank duck blood tested positive for the H₅N₁ poultry virus after being admitted to the hospital with high fever on Fri 1 Apr 2005 in the central province of Ha Tinh
• a woman was taken to hospital in Hue on Sun 3 Apr 2005
• a 10-year-old girl died on 27 Mar 2005 in St. Paul's Hospital in Hanoi and tested positive on Mon 4 Apr 2005
• 2 other patients have been diagnosed with the H₅N₁ virus in the northern provinces of Ha Tay and Hung Yen between 2 and 8 Apr 2005, but no deaths were reported
• a 20-year-old Cambodian woman from Kampot province (the home of 4 other people who died of H₅N₁ in 2005) developed symptoms since beginning of May, was treated at a private clinic in Cambodia before being transferred on Wed May 11 2005 to the General Hospital in Vietnam Kien Giang province, which borders Cambodia, with a suspected H₅N₁ infection. She is in stable condition. Her high fever and coughing have almost disappeared, but 2 x-rays of her lungs showed serious damage. Dead chickens were reported in her neighborhood a month ago. The woman's samples have been sent to the Pasteur Institute in Ho Chi Minh City for testing. Preliminary tests on May 16 showed she was not infected by the virus, but

more tests were being conducted.
• a 55-year-old man (Cao The Hai) from Vinh Phuc province, tested positive on May 13 at the Institute of Tropical Diseases in Hanoi. The new case comes after a 3-week period without any reported human or poultry cases. Such lulls have sometimes prompted authorities to declare victory over avian flu.
• a 52-year-old man from the northern province of Vinh Phuc was hospitalized with a fever last Thu 12 May 2005 after eating the chicken with his family, tested positive on May 16 (the country's 1st human case in a month) and remained in stable condition on Tuesday at Bach Mai Hospital in Hanoi
• a 58-year-old man from northern Thanh Hoa province, some 160 km south of Hanoi had AI-like symptoms of high fever, coughing and breathing difficulties on 20 Apr 2005, were admitted to Bach Mai Hospital in Hanoi and tested positive for the virus on Sun 15 May 2005. There were dead chickens reported in the man's neighbourhood a month ago and his family also slaughtered chickens for meals
• 3 additional human cases of infection with H₅N₁ avian influenza virus were confirmed in Hanoi during the last 2 weeks of May 2005. All the 3 have been infected in relation to sick poultry
• a 30-year-old man discharged from Hospital
• 2 women from the northern provinces Thanh Hoa and Vinh Phuc are still being treated in a Hanoi hospital
The most recently detected case was reported on 26 Apr 2005. In the same communication, an additional death from the disease that was earlier reported as a suspected case was confirmed. Last month, health officials said a 46-year-old man from the northern province of Hung Yen, 65 km (40 miles) southeast of Hanoi, was suspected of having died of the H₅N₁ virus.
• 6 people from Vietnam's northern region have just been found to have contracted bird flu virus strain H₅N₁ and admitted to Tropical Diseases in Hanoi capital city, which is now treating 8 bird flu patients in all : 7 are showing good signs of recovery, and 1 is in critical health condition.
• between 1 to 17 Jun 2005, 4 cases of human infection with H₅N₁avian influenza virus were reported
• 2 of the patients are from Hanoi
• a 73-year-old Vietnamese Hanoi resident, one of 4 people infected by the H₅N₁ virus being treated in hospital, died on Tue 28 Jun 2005 after being admitted on Thu 23 Jun 2005
• 1 is from the nearby province of Hai Duong
• 1 is from the central province of Nghe An
All 4 of the patients are alive. At present, a total of 7 patients are being treated for H₅N₁ avian influenza at a hospital in Hanoi.
• a male  doctor at the institute, who has taken specimens from bird flu patients for testing, was found infected on Fri 17 Jun 2005, but a

2nd test turned up negative.
11 avian influenza patients have been hospitalized at the National Institute for Clinical Research of Tropical Medicine in Hanoi. The center is also treating 12 suspected avian influenza cases. Their conditions are all "relatively stable".
2 patients and 3 suspected cases were admitted to the Institute of Tropical Diseases in Hanoi capital city from June 18-19. Currently, the institute is treating 28 people with bird flu symptoms, of whom 13 have been tested positive to H₅N₁.
• one positive case in the northern province of Ha Tay in May 2005
• bird flu has killed another Vietnamese on Jul 14, taking the country's toll to 40, and infected 3 more of 18 patients in the isolation ward of Hanoi's National Institute for Clinical Research of Tropical Medicine. 13 others were suspected of being infected with the virus, while 2 had the human influenza.
• a 72-year-old man from Hanoi died June 28
• a 24-year-old man named Le Hoang Anh from southern Tra Vinh province died Mon 25 Jul 2005 and tested positive on Thu 28
• a 26-year-old woman named Doan Thai Truc in southern Ho Chi Minh City died Wed 27 Jul 2005 and tested positive on Thu 28
• a 49-year-old woman named Nguyen Thi Them from the Quoc Oai district in northern Ha Tay province developed symptoms on Jul 15, received treatment at a provincial hospital for 3 days starting on 27 Jul 2005. The woman had bought a chicken at a local market and cooked it. She tested positive on Aug 2 and remains hospitalized.
• a 35-year-old man from Ben Tre Province in the Mekong Delta developed symptoms on 25 July 2005 and died on July 31, a day after he was taken to hospital with a high fever. The man slaughtered and ate 2 chicken that had the H₅N₁ virus. He retrospectively tested positive in September^ref
• a 30-year-old man from Tan Xuan Commune, southern Ben Tre Province, ate sick fighting cocks after slaughtering them, was admitted to Nguyen Dinh Chieu Hospital with acute pneumonia at the end of July 2005, died the day after, and tested positive for the H₅N₁ virus. His is the 1st death from avian influenza virus infection in Ben Tre province.
• a ?-old male/female ? from Soc Son, a district on the outskirts of Hanoi, died from acute pneumonia on Sun Aug 28, and tested positive for H₅, but the government had not spotted any outbreaks in poultry in August
• a 14-year-old girl and a 26-year-old man from Quang Binh province ate duck and a chicken's egg around a week before they became ill. The girl was admitted to hospital on 21 Oct 2005 and died on 23 Oct 2005, and the man died 26 Oct 2005 within an hour of arriving at the hospital. Their bodies had been sent home to be buried. the victims were not related and from different towns in the province, which is around 500 km (310 miles) south of the capital Hanoi. These are the first human cases of avian influenza to be reported from Viet Nam since the end of August 2005. It seems that the deaths of these 2 unrelated patients have been attributed to avian H₅N₁ influenza virus infection on the basis of clinical assessment alone, and that no laboratory testing has been undertaken, nor is likely to be undertaken since the bodies of the patients have been returned to their families. Therefore the status of these cases remains "suspected" and may remain so. On Nov 3 the Saigon Giai Phong (Liberation) newspaper quoted Deputy Health Minister Trinh Quan Huan as they were negative for bird flu
• a 27-year-old man with symptoms of the disease had been sent to a better-equipped hospital in Hue City, central Viet Nam, for treatment
• a 25-year-old woman in Hanoi woman was rushed to hospital on Tue 1 Nov 2005 with respiratory difficulties and a slight fever, symptoms; her mother said she bought a slaughtered chicken for a family meal of 4 people but that only her daughter became sick.
• a 24-year-old pregnant woman from Bac Giang province (where bird flu has infected poultry in 3 communes, killing > 3000 chickens, ducks and geese) was admitted to hospital with a fever and respiratory problems; she tested negative for H₅N₁
• a 35-year-old man from Hanoi developed a slight fever after eating with his family a prepared chicken bought from a market near his house in the Dong Da District of Hanoi on Oct 22, was taken to Bach Mai hospital on October 26 with respiratory difficulties, died on October 29, and on Nov 8 was confirmed as the first human victim of the latest outbreak. Other family members did not show any symptoms of bird flu
• a 68-year-old man in the central province of Quang Tri was admitted to the General Hospital in Hue city on Nov 5 with a critical lung infection and fever and died on Sun Nov 6, but there is no confirmation of bird flu infection yet
• a 43-year-old man from the northern city Hai Phong ate poultry during his stay in the southern city of Vung Tau, was admitted to a hospital on 1 Nov 2005 after returning home, died on 2 Nov 2005 from respiratory failure and tested positive for H₃N₀. The diagnosis of H₃N₀ is clearly erroneous:

possibilities are that the patient has contracted H₃N₂ human influenza virus infection or even H₃N₈ avian virus infection (a combination of H and N antigens found previously in ducks). Alternatively the N₀ designation may mean no more than that the subtype has not been identified.
• a student was being tested in hospital after eating chicken eggs on Fri 11 Nov 2005
• a 78 year old woman died from serious pneumonia in the central province of Quang Binh on Fri 11 Nov 2005.
• a man suspected of being infected with the H₅N₁ strain fled a hospital quarantine unit on Nov 25, 2005. Officials in his home province have been trying to persuade him to return to the hospital
• a 15-year-old boy from Hai Phong Province developed symptoms on 14 Nov 2005, was hospitalized on 16 Nov 2005, tested positive on 25 Nov was discharged from hospital and is recovering.
• a 3-years old toddler from the southern province of Hau Giang died on Mon 12 Dec 2005, 7 hours after admission to hospital for severe lung infection with symptoms pointing to bird flu infection but repeated tests showed he did not have that virus. The child's illness was ascribed similarly to the

onset of colder weather and the prevalence of human influenza virus infections.
• a 36-year-old male teacher from the southern province of Soc Trang died on Dec 2?, 2005, but tests showed he not have H₅N₁ virus. Chicken is traditionally offered to ancestors at Tet, which falls in late January in 2005^ref

(total : 93 cases in 28 cities and provinces since 26 Dec 2003 (66 from 21 cities and provinces since 16 Dec 2004 [40 according to WHO]) according to Vietnamese authorities; 42 deaths since Dec 2003 [40 according to WHO] (23 since 30 Dec 2004 [22 according to WHO]))^ref. Viet Nam has so far experienced 3 outbreaks of bird flu in humans, killing 32 local people. In the 1st outbreak, lasting from 26 Dec 2003 to 10 Mar 2004, a total of 23 people were infected with H₅N₁ virus, of whom 16 died. In the 2nd outbreak from 19 Jul 2004 to 26 Aug 2004, 4 people contracted the virus, and all of them died. In the most recent outbreak starting 16 Dec 2004, Viet Nam has identified 41 local cases of avian influenza H₅N₁ virus infection, of whom 16 have died, 5 have fully recovered, and one remains hospitalized. The drop in the bird flu mortality rate was more marked in northern Vietnam than in the south. While the virus in southern Vietnam is still killing at the same pace as last year, the rate in the area around Hanoi and elsewhere in the north has dropped from that level to as low as 20%. Vietnamese health experts said their suspicion that the disease is shifting is further supported by preliminary research showing a genetic change in the virus in the north resulting in the production of a protein with one less amino acid than in the south. The mortality rate for bird flu in Vietnam in 2005 is about 35%, almost exactly half that of 2004.
As of Mon 28 Feb 2005 the number of unofficial cases (i.e., the aggregated WHO, press and governmental figures) in East Asia from Jan 2004 to the present is 65 with 46 deaths; whereas the official (WHO) figures are 55 cases and 42 deaths. During the period 28 Jan 2004 to 25 Oct 2004, the unofficial and the official figures are the same: i.e. Thailand 17 cases and 12 deaths; Viet Nam 27 cases and 20 deaths; giving totals for East Asia of 44 cases and 32 deaths. The numbers of cases reported from mid-Dec 2004 to 28 Feb 2005 are:
• country / unofficial (official) cases / unofficial (official) deaths
• Cambodia / 1 (1) / 1 (1)
• Thailand / 0 (0) / 0 (0)
• Viet Nam / 20 (10) / 13 (9)
• total / 21 (11) / 14 (10)
Vietnamese and international Media reports would suggest WHO's case count is falling seriously behind what is happening on the ground. In the past week alone, four human cases have been reported. WHO's most recent case count -- dated 2 Feb 2005 -- sets the number of human cases of H₅N₁ infection since January 2004 at 55, with 42 deaths. But tallies kept by the Center for Infectious Disease Research and Policy at the University of Minnesota tell another story.
Since 31 Jan 2005, WHO has received > 90 clinical specimens sampled between 24 Dec 2004 and 29 Jan 2005 from confirmed and suspected H₅N₁ human cases in Viet Nam. Antigenic and genetic analyses are being conducted in the WHO Collaborating Center for Reference and Research on Influenza and the WHO H₅ Reference Laboratory in the National Institute of Infectious Diseases, Japan. So far, 9 viruses have been isolated from specimens collected from southern Viet Nam. Results show that:
• these viruses belong to group Z and are genetically highly similar to the viruses isolated in 2004, including A/Vietnam/1194/2004 and A/Vietnam/1203/2004, which are the prototype vaccine strains recommended by WHO for pandemic influenza vaccine production.
• except for one virus, all the rest are antigenically closely related to A/Vietnam/1194/2004 and A/Vietnam/1203/2004.
• at the receptor recognition site, there appears to be an avian receptor preference.
The conclusions so far:
• very little mutation has been observed since 2004.
• there is no need to change the prototype pandemic vaccine strain selected by WHO in 2004
• genetically, the viruses continue to show resistance to amantadine.
The continued prevalence of human cases of avian influenza in Viet Nam, and not elsewhere in East Asia, might indicate that there are social and/or genetic factors peculiar to the Vietnamese population that remain to evaluated.
Global Public Health Intelligence Network (GPHIN) : an Internet trolling program developed and maintained by Health Canada.
Viet Nam may have 2 problems with its data on human cases: transparency in reporting and accuracy in testing. The country has lapsed in its reporting of cases to the WHO. > 1 month passed without official reporting of cases, despite widespread media reports of several new cases. Ongoing monitoring by Center for Infectious Disease Research & Policy (CIDRAP) News, Academic Health Center, University of Minnesota also shows substantial discrepancies between official and unofficial numbers^ref. Because the WHO relies on official reports for its case counts and as the basis for advice to member countries, the lack of reporting has an impact. WHO officials had requested reports in person and in writing. The pattern of cases in Viet Nam has not changed recently. The press reports suggest that the missing cases are sporadic^ref
• reanalysis of samples from Vietnamese patients with flu-like symptoms has revealed on the 3rd week of Feb 2005 that some people originally declared free of avian influenza actually did carry the avian influenza A (H₅N₁) virus. Reassuringly, preliminary genetic analyses at the National Institute of Infectious Diseases (NIID) in Tokyo show that the virus has not mutated greatly since 2004. The death rate for infected patients has so far been very high; 10 of the 11 cases identified in Viet Nam since December 2004 have died, but if many more cases are going unidentified, the mortality rate could be much lower. Samples from the 11 recent cases of avian influenza in Viet Nam, plus those from some 90 suspected cases that tested negative for H₅N₁ virus, were recently sent to the NIID for study. About 1/3 of the samples have been examined so far, and, of these, 7 of the negative results have tested positive. All 7 are said to have recovered from the disease. Fresh tests at Pasteur Institute in Viet Nam on the 3rd week of Feb 2005 confirmed 4 of these positive results. Part of the discrepancy between labs could be accounted for by problems with the original tests. Some reagents were not mixed well, and the results weren't clear. But for 3 cases, the Pasteur researchers -- together with NIID researchers observing -- reconfirmed their earlier negative diagnosis. This is worrying, as it suggests that the Vietnamese test is not sensitive enough to detect all cases. The institute now plans to switch to the more sensitive test used in Tokyo and will ensure better training for its technicians. If many infections have been missed, suspected cases of human-to-human transmission should be investigated again. There has so far been only one documented case of probable human-to-human transmission, but there are strong suspicions that clusters of disease within Asian families may have been transmitted through people rather than birds. The Japanese data now favor an interpretation that avian influenza virus infection of humans is widespread and mostly unapparent. If confirmed, such data should be a cause for rejoicing rather than a reason for generating further alarm and despondency^ref.
• researchers tested hundreds of stored blood samples using Western blotting to see if these showed evidence of antibodies to H₅N₁ virus. Rumors on 25 Jun 2005 are that scores of samples came back positive. As a consequence the Vietnamese authorities have asked for international assistance. The official explanation for this diffidence is the possibility the western blotting is not sufficiently specific to rule out the possibility that it is detecting antibodies to other influenza serotypes than H₅N₁, although for other viruses "westerns" are used as confirmatory tests because they are more specific than the conventional ELISA tests. Westerns are antibodies against antibody tests and are not especially easy to do, but are easier and less hazardous than the current gold standard, the neutralization test which uses live H₅N₁ virus and tissue culture cells.
The Institute of Hygiene and Epidemiology will soon start testing a vaccine on monkeys, chickens and mice with the hope of using it on humans and poultry, as the vaccine has been under research since April 2004.
Between 1-10 Jan 2004 22 new outbreaks had been reported in 7 provinces in the Central Highlands and southern regions at a limited number of farms^ref :
• ... / species / susceptible / cases / deaths / destroyed / slaughtered
• An Giang (hundreds of chickens and ducks have suddenly died since mid-December)
• Bac Lieu / avi / ... / 160 / 110 / 50 / ...
• Ben Tre
• Binh Phuoc / avi / ... / 125 / 30 / 95 / ...
• Can Tho city / avi / ... / 3665 / 205 / 3460 / ... (> 200 chickens raised by Tao Van Loi in Binh Thuy district died on 12 Dec 2004. The local veterinary force culled his 3685 chickens and 4541 eggs worth some 200 Vietnamese dong (12,700 USD) after finding that samples from the dead fowl tested positive for H₅. In mid-December, the force also killed 24 chickens raised by 2 other farmers in the same district, since samples were tested positive to the virus strain. Can Tho's veterinary force sprays antiseptics and bans the transport of poultry in the areas within a radius of 1 km. In Can Tho city, tests on poultry samples taken from the Co Do poultry farm in Vinh Thanh district, Phu Thu ward in Cai Rang precinct, Dinh Mon commune in Co Do district and Trung Kien commune in Thot Not district showed that ducks in these localities have contracted the H₅ virus. The H₅ virus was also detected in serum samples of 460 other ducks in Tan Tao A ward, Tan Binh precinct, on 5 Jan 2005. > 25,700 poultry have been culled as a precaution. The MARD is instructing provinces to keep close watch on poultry flocks and immediately cull infected chickens. Veterinarians have culled up to 11,000 chickens, ducks, quail, and geese to try to contain the virus.
• Hau Giang / avi / ... / 800 / 500 / 300 / ... (some 200 out of 540 chickens in Hau Giang's Long My rural district died last week. Other healthy fowl in the flock have already been culled)
• Long An / avi / ... / 4900 / 3700 / 1200 / ...
• Tra Vinh / avi / ... / 1100 / 300 / 800 / ...
• total / avi / ... / 10 750 / 4845 / 5905 / ...
• Nam Dinh province, Truc Ninh district  / avi / ... / 250 / 917
• Dong Thap
• Tien Giang
• Lam Dong (Central Highlands)
The busy transport and big sales of poultry during the Lunar New Year Festival (in early February 2005) plus complex weather may result in outbreaks in the northern region. Denmark on Dec 20 offered 12 southern localities equipment for bird flu prevention worth some 150,000 US dollars. The equipment includes sprayers, slaughtering tools and protective clothes. Vietnam remains highly alert to potential new outbreaks of bird flu this winter, because cold weather favors the spread of the disease. Free raising of poultry, especially ducks in fields, and rampant transport and sale of fowl before the Lunar New Year, which falls in early February, are also contributing factors to the high risk for the return of bird flu. The country is intensifying anti-bird flu activities such as frequently disinfecting farms, monitoring the transport and import of fowl and their eggs via border gates, and raising public awareness of the disease nationwide, especially in the southern Mekong Delta. It plans to vaccinate poultry if large-scale resurgence of bird flu is reported. According to the Department of Animal Health, since December 2004 to Jan 7, a relapse of bird flu has been seen in 25 communes in 11 localities, namely the southern city of Can Tho, the northern province of Nam Dinh and the 9 southern provinces of Dong Thap, Tien Giang, Long An, Bac Lieu, Ca Mau, Hau Giang, Tra Vinh, Binh Phuoc and An Giang, killing and leading to the forced culling of some 28 700 fowl, mainly ducks and chickens. 54 bird flu outbreaks were found in 51 communes belonging to 29 districts of 9 provinces between 1 and 10 Jan 2005. The Central Highlands province of Lam Dong, the southern provinces of Binh Phuoc, Ben Tre, Tien Giang, Long An, Dong Thap, Bac Lieu and Ca Mau, and the Mekong Delta city of Can Tho have culled > 103,000 infected poultry. The disease seems to spread rapidly; just 3 days before, the Vietnamese authorities mentioned outbreaks in 20 communes and 15 districts of 7 cities and provinces. The 2 added (southern) provinces are Bac Lieu and Ca Mau^ref. By 13 Jan 2005, the country experienced as many as 84 outbreaks in 16 cities and provinces, including Hau Giang, Bac Lieu, Tra Vinh, Long An, Dong Thap, An Giang, Binh Phuoc, Can Tho, Tien Giang, Kien Giang, Ca Mau, Nam Dinh, Lam Dong, Ben Tre, Ha Nam (the first northern province : a flock of 100 ducks in Ly Nhan district) and Hanoi (in a flock of 400 ducks, a flock of 600 chickens in Long Bien urban district), which have killed and led to the forced killing of nearly 168,000 fowl. According to the Veterinary Department, by Jan 17, the epidemic spread to 136 communes of 62 districts in 18 cities and provinces, including Lam Dong, Binh Phuoc, Ben Tre, Tien Giang, Long An, Dong Thap, Can Tho, Bac Lieu, Hau Giang, Tra Vinh, An Giang, Ca Mau, Ha Nam, Hanoi, Tay Ninh, Dong Nai, Ninh Thuan and Quang Nam^ref. A total of 75,454 chickens, 73,703 geese, and 104,850 quail have been culled between 1-16 Jan 2005. Fearing that severe outbreaks of bird flu will happen during the Lunar New Year Festival (early February 2005), when cold weather favors the development of viruses and a larger number of fowl are transported and traded, local veterinary forces are increasing surveillance of areas formerly hit by bird flu, covering poultry farms, markets and slaughterhouses. They attach great importance to monitoring transport and trade. The country's veterinary forces nationwide in the 1st week of January 2005 resumed a 24-hour operation to monitor transport and trade, an operation that was initially applied in early 2004, when bird flu was at a peak in the country. Veterinary cadres are to go deeply into wards and hamlets to monitor poultry flocks so that Viet Nam's