TROPICAL MEDICINE : medical science as applied to diseases occurring primarily in tropical and subtropical countries. Sometimes called geographic medicine because diseases of interest to tropical medicine specialists may also occur in developing countries or areas in the temperate climate zones

• emporiac or travelers' medicine : the subspecialty of tropical medicine consisting of the diagnosis and treatment or prevention of diseases of travelers (see also vaccines for travelers) : with all international travel, consult a health-care provider 4-6 weeks beforehand for any necessary vaccines, medications, and additional advice

Factors influencing the change of the epidemiology and the mode of presentation of infectious diseases :
• climate changes
• industrial and economic development
• mass movements, civil unrest and war
• changing global food production and consumption patterns
• increased life expectancy
• grouping of susceptibles
• increasingly frequent and ever-faster travel
• changing technology
• microbial genome change and adaptation
• health care delivery system
Population subsets at risk : 20% of Europeans (expected to increase significatively over the next century), including elderlies, pregnants, newborns, immunocompromised or patients discharged early from the hospital into the community.
10⁹ air travels per year, of which 5 x 10⁷ from industrialized to developing countries. 20-70% of travelers develop a disease lasting on average 3 days out of 14 : only 1-5% of affected travelers will require health care intervention and a few will die
Risk factors :
• previous health status
• travel
• air travel : civil air traffic moves in an altitude that is dangerous for human beings without technical aids
• low temperature (hypothermia) and humidity
• reduced air pressure (hypobarism) combined with oxygen pressure (hypoxia)
• seasonal depending high concentration of ozone and cosmic radiation
• jet lag
• economy class syndrome
• contact with permethrin, because of aircraft disinsection before take-off out of tropical countries where vector-borne diseases are endemic
The aim of an airline is to offer good cabin air quality, comfort and security for all passengers, may they be healthy, old, disabled or sick. Medical incidences on board arise and passengers expect modern equipment such as doctor's kit and defibrillators^ref
• place
• lifestyle : leisure activities and infection
• exotic, trendy and traditional cuisine (e.g. sushi, sashimi, ...) : Anisakidae, Vibrio, Listeria, Toxoplasma gondii, HAV, Gnathostoma, Diphyllobotrium, Taenia, Trichinella spiralis
• outdoor activites : Borrelia, Ehrlichia, Giardia intestinalis
• aquatic environments (swimming pools, whirlpools, spas) : Legionella pneumophila, Pseudomonas aeruginosa, MOTT, amoebae
• poisoning and intoxications from fish and mollusks :
• amnesic shellfish poisoning (ASP)
• diarrhetic shellfish poisoning (DSP)
• neurotoxic shellfish poisoning (NSP)
• paralytic shellfish poisoning (PSP)
• scombroid syndrome
• ciguatera fish poisoning (CFP)
• tetrodotoxin
• traumas and poisoning from vertebrate and invertebrates : coeloenterates, echinodermata and mollusks (e.g. medusae, stonefish)
• skin, soft tissue and mucosal infections and overinfections : Mycobacterium marinum, Aeromonas hydrophila, Vibrio spp., Pseudomonas aeruginosa, Chromobacterium violaceum, Enterobacteria, Staphylococcus aureus, Streptococcus pyogenes (erysipela)
• living with pets : Campylobacter jejuni, Salmonella spp., Pasteurella spp., Bartonella spp., Cryptosporidium spp.
• sex : HIV, GC, Chlamydia trachomatis, HBV
• duration
Main traveler's diseases :
• injury : in earlier studies of deaths of Americans overseas, some 10,000 deaths were analyzed according to cause, age, and place of occurrence^{ref1, ref2}. There were 601 deaths from injuries and only 25 deaths caused by infectious diseases. Death rates from injuries in developing countries were considerably higher than those in the United States. Similar findings came from an earlier study involving Peace Corps volunteers^ref. Travel clinics would be seriously remiss if they did not counsel travelers on the dangers of injuries. Advice to avoid motorcycles, small vehicles, unscheduled aircraft, and swimming in unfamiliar waters is essential to help protect travelers^ref. The literature indicates that about 25% of overseas deaths are from injury, with the remainder largely from natural causes^{ref1, ref2}.
• infectious diseases^ref :
• traveler's diarrhea (viruses : Norwalk virus, rotaviruses, SRSV; bacteria : ETECs, Campylobacter jejuni, Shigella, Salmonella spp., Aeromonas hydrophila, Vibrio parahemolyticus; parasites : Giardia intestinalis, Entamoeba histolytica, Cryptosporidium, Cyclospora, Isospora, Dientamoeba)
• respiratory infections
• arthropod-borne diseases
• sexually-transmittable diseases (STDs)
• animal bite-borne disease
• fresh- or salt-water-borne diseases
• blood-borne diseases
Preventable diseases (the "3-rule") : MacPherson et al. estimated that about 36% of all overseas deaths are preventable^ref.
• infectious diarrhoea (30%)
• malaria (3%) :
• at risk travelers = 70 millions people per year
• incidence among travelers = 30,00 new cases per year
• "airport malaria", representing the inadvertent transport of live mosquitoes aboard aircraft arriving from tropical regions, has become a worrying problem in recent years. Physicians generally have little reason to suspect malaria, as the sufferers may never have travelled to a region where the disease is endemic and the symptoms can sometimes be confused with flu. Since 1969, 13 countries reported a total of 89 cases of malaria in people living near an airport^ref. In the USA, 4 cases of confirmed or suspected airport malaria were reported between 1987 and 1998^ref. In European cases of airport malaria the delays in correctly diagnosing the disease have led to the patients developing complications. In one Swiss case of airport malaria, 31 days elapsed before a correct diagnosis was made^{ref1, ref2}

Prevention : aircraft disinsection is required by various countries. Aircraft disinsection with aerosol insecticides during flight has generally been held to be inadvisable because it was assumed that the insecticides would be rapidly removed by the cabin air-conditioning system : "top-of-descent" disinsection has been introduced as the recommended procedure^ref. In-flight spraying with a 2% phenothrin aerosol exposes passengers and crew directly. Residual spaying uses a permethrin emulsions in the absence of passengers and crew and results in dermal and oral exposures. Exposed passengers and crew often complain of, skin rashes, respiratory problems, tingling and numbness in fingertips and lips and burning eyes. Volatile organic compounds (VOCs) are found in all aerosol preparations including, ethyl benzene and xylene isomers along with phenothrin. Residual sprays contain, cis-, and trans-, permethrins, palmidrol, and occasionally naphthalene. Headspace analysis found methylene chloride and hexene derivatives but not the active ingredients. The known synergistic effects between organophosphates and pyrethrins, based on carboxyesterases inhibition, can be expected in the presence of tricresylphosphates (TCPs), constituents found in jet engine oils and in some hydraulic fluids. During oil seal failure, the presence of TCP in the ventilation air could explain the increased sensitivity of some crew members and passengers to disinsectants^ref.
• HAV (0.3%)
• typhoid fever (0.03%)
Web resources :
• Committee to Advise on Tropical Medicine and Travel (CATMAT)
• For Traveller's Health (FORTH)
• International Society of Travel Medicine (ISTM)
• GeoSentinel
• International Travel and Health (ITH) at WHO



• International Travelers Clinic by the Medical College of Wisconsin
• MCW HealthLink: Travel Medicine
• Travel Health Online
• TravelMedCare New York
• Travel Medicine Clinic
• Travel Medicine Consultants
• Travellers Medical and Vaccination Centre (TMVC)
• Travelers' health at CDC
• The yellow-covered book, officially titled "CDC Health Information for International Travel 2007-2008,"
• The Arlington Travel Clinic
• The Fleet Street Clinic

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