Venomous snakebites result in almost 125,000 deaths per year worldwide (20,000 in Africa). Tetanus could follow snakebite in inaccessible rural agricultural communities with inadequate health care provision. Clinical presentation is typical but late and is confounded by snakebite complications leading to considerable morbidity and mortality^ref.

• poisonous or venomous snakes / thanatophidia / toxicophidia : snakes that secrete substances (venoms) capable of producing a deleterious effect on either the blood (hemotoxin) or the nervous system (neurotoxin); the venom is injected into the body of the victim by the snake's bite

• metalloproteinase-disintegrin family proteins target GPlba (mocarhagin, crotalin), GPVI (alborhagin) or GPIa-IIa (jararhagin), resulting in inhibition or induction of platelet aggregation by proteolytically dependent or independent mechanisms.
• C-type lectin-like proteins (CLPs) of snake venom have a variety of biological properties, acting for example as anticoagulants, procoagulants, and agonists/antagonists of platelet activation. The structural and functional studies of the first identified CLP, factor IX/factor X-binding protein (FIX/Xbp), have led to an understanding how new functionally heterodimeric CLPs from monomeric C-type lectin related proteins may have evolved by 3D domain swapping, and have contributed to our understanding of the significance of magnesium ions in the blood coagulation cascade reaction. 2 metallo-proteases, carinactivase and RVV-X, with C-type lectin-like domains, were isolated, characterized, and found to be useful in the study of the properties of prothrombin and coagulation factor X. There are also several unique CLPs belong to agonists and antagonists of platelet receptors, platelet glycoprotein Ib and glycoproteins Ia/IIa and VI, collagen receptors and the following CLPs that modulate platelet function. These CLPs may provide the new insights into platelet function: alboaggregin-B, echicetin, botrocetin, bitiscetin, flavocetin-A, aggretin/rhodocytin, convulxin, and agkistin^ref.bothrojaracin, Bothrops jararaca lectin. Members of the C-type lectin family interact specifically with GPIba (echicetin, alboaggregin-B, agglucetin), GPVI (convulxin, ophioluxin) or GPIa-IIa (rhodocetin), whereas related proteins accomplish dual receptor occupancy and bind GPVI and GPIba (alboaggregin-A, alboluxin), or GPIba and GPIa-IIa (aggretin). These latter venom proteins mimic physiological ligands, vWF or collagen, which also recognize more than one receptor^ref

• snake venom thrombin-like enzymes (SVTLE) are used for fibrinogen and fibrinogen breakdown product assays as well as detecting dysfibrinogenaemias. Since SVTLE are not inhibited by heparin, they can be used for assaying antithrombin III in samples containing heparin.
• snake venom prothrombin activators are utilised in prothrombin assays
• Russell's viper venom (RVV) can be used to assay clotting factors V, VII, X and lupus anticoagulants (LA)
• activators from the Oxyuranus scutellatus scutellatus, Australian brown snake and Echis carinatus have also been used to assay LA
• protein C (PC) and activated PC (APC) resistance can be measured by means of RVV, Protac and STA-Staclot
• von Willebrand factor can be studied with botrocetin.
• snake venom C-type lectins and metalloproteinase disintegrins are being used to study platelet glycoprotein receptors and show great potential for use in the routine coagulation laboratory^ref.

• Squamata
• Scleroglossa
• Anguimorpha
• Helodermatidae
• Heloderma
• Heloderma suspectum (a.k.a. Gila monster)

=> serotonin
=> bradykinin-releasing substance
=> protease
=> hyaluronidase
=> helodermin and helospectin are peptides structurally similar to VIP
=> gilatoxin
Immediate signs and symptoms include pain at the bite site, edema, nausea and vomiting, weakness, diaphoresis, and dizziness (without a decrease in blood pressure), persistent hyperesthesia, which eventually abated. Two types of helodermatid bites produce distinct clinical pictures. The chewing bite potentially causes more envenomation than the slashing bite. No antivenin is commercially available. Treatment is supportive, and although first aid measures such as suction or compression may impede venom movement, they are unproved. Cryotherapy, tourniquet, and excision are dangerous and should not be used.
• Serpentes
• Colubroidea
• Elapidae
• Acanthophiinae
• Acanthopis
• Acanthophis antarcticus (a.k.a. (common) death adder)

=>
• Notechis
• Notechis scutatus (a.k.a.common tiger snake) : Australian snake whose body is chiefly brown with dark bands
• Notechis scutatus scutatus

=> notexin : it acts as a PL-A₂.
• Oxyuranus
• Oxyuranus scutellatus
• Oxyuranus scutellatus scutellatus (a.k.a. Australian taipan)

=> taicatoxin (TCX) : it blocks L-type voltage-gated Ca²⁺ channels
=> taipoxin : it is made up of a, b₁, b₂ (phospholipases) and g (serpin) subunits and binds to NPTX1.
• Pseudechis
• Pseudechis porphyriacus (red-bellied black snake), a large venomous semiaquatic Australian snake whose body is black on top and red underneath.
• Pseudonaja
• Pseudonaja textilis (a.k.a. eastern brown snake)
• Bungarinae
• Bungarus
• Bungarus fasciatus (a.k.a. banded krait)
• Bungarus multicinctus (a.k.a. Taiwan banded krait)

=> a-bungarotoxin (a-BTX / BuTx) : it is an irreversible antagonist on N AChR
=>b-bungarotoxin (b-BTX / BuTx) : it is a dimer composed of chain A, a phospholipase A₂ subunit, and chain B, a subunit that binds certain voltage-gated K⁺ channelsat the pre-synaptic membrane. Targeting chain A to the K⁺ channel facilitates destruction of the synaptic vesicle and the presynaptic membrane by the enzyme, resulting in impacting of membrane proteins (voltage-gated Na⁺ channels, voltage-gated K⁺ channels, Na⁺/K⁺ ATPase, voltage-gated Ca²⁺ channels, Ca²⁺ ATPase, synaptophysin, synaptobrevin, synaptotagmin, syntaxin and SNAP-25) and blocking of ACh release.
=> g-bungarotoxin (g-BTX / BuTx) acts at the pre-synaptic site
• Elapinae
• Dendroaspis
• Dendroaspis augusticeps (a.k.a. eastern green mamba)

=> a-dendrotoxin (a-DTX)
=> b-dendrotoxin (b-DTX)
=> g-dendrotoxin (g-DTX)
=> d-dendrotoxin (d-DTX)
=> dendrotoxin A
=> dendrotoxin B
They all block voltage-gated K⁺ channels.
=> muscarinic toxin 3 (MT3) : it inhibits M4 AChR.
• Dendroaspis polylepis
• Dendroaspis polylepis polylepis (a.k.a. black mamba)

=> dendrotoxin I
=> dendrotoxin K
They all block voltage-gated K⁺ channels.
=> calciseptine blocks L-type voltage-gated Ca²⁺ channels
• Naja spp. (cobras)
• Naja atra (a.k.a. Chinese or Taiwan cobra)
• Naja kaouthia (a.k.a. monocellate cobra)
• Naja mocambique mocambique

=> mocarhagin, a metalloproteinase, cleave selectively 2 mucin-like substrates on platelets and neutrophils within anionic amino acid sequences containing sulfated tyrosines. Purified mocarhagin has haemagglutinin activity, and a similar profile for inhibition of mocarhagin-dependent haemagglutination and proteolysis suggests that the lectin-like domain may account for its substrate specificity^ref.
• Naja naja
• Naja nigricollis (a.k.a. black-necked spitting cobra)
=> cobrotoxin / cobra venom factor (CVF) : it is an antagonist of N AChR (used as therapy for paralytic poliomyelitis) and acts as a cofactor for factor D in cleaving factor B
• Ophiophagus spp.
• Ophiophagus hannah (a.k.a. king cobra)

=> ophioluxin, a convulxin-like C-type lectin, is a powerful platelet activator via glycoprotein VI^ref
=> cobrotoxin
• Hydrophiinae
• Enhydrina
• Enhydrina schistosa (a.k.a. common beaked sea snake)
• Laticaudinae
• Laticauda
• Laticauda semifasciata (a.k.a. broad-banded blue sea krait, Erabu sea snake)

=> erabutoxin : it is an antagonist of  N AChR
•  Hydrophiidae (sea snakes)
• Hydrophis
• Hydrophis spiralis

=> envenoming^ref
• Viperidae (true vipers / viperine snakes)
• Crotalinae
• Agkistrodon
• Agkistrodon acutus

=> agglucetin acts as a glycoprotein Ib agonist
=> agkislysin is a novel P-I class metalloproteinase with broad substrate-cleaving activity^ref
• Agkistrodon bilineatus

=> bilinexin, a snake C-type lectin, agglutinates platelets via GPIb and a₂b₁^ref
• Agkistrodon contortrix
• Agkistrodon contortrix contortrix (southern copperhead)

=> Protac
=> fibrolase, a fibrinolytic zinc-containing metalloproteinase
• Agkistrodon contortrix laticinctus (broad-banded copperhead)

=> myotoxic Asp⁴⁹ phospholipase A₂ (ACL-I PLA₂)
• Atropoides
• Atropoides nummifer (a.k.a. Porthidium nummifer)

=> myotoxin II, a Lys⁴⁹ catalytically inactive phospholipase A(2) homologue
• Bothrops spp.
• Bothrops asper (a.k.a. terciopelo)

=> myotoxin
• Bothrops atrox (a.k.a. barba amarilla, fer-de-lance)
• Bothrops colombiensis
• Bothrops jararaca (a.k.a. jararaca)

=> bothrojaracin
=> Bothrops jararaca lectin
=> botrocetin is a snake venom protein that enhances the affinity of the A1 domain of plasma von Willebrand factor (vWF) for the platelet receptor glycoprotein Ib (GPIb), an event that contributes to bleeding and host death. Here we describe a kinetic and crystallographic analysis of this interaction that reveals a novel mechanism of affinity enhancement. Using high-temporal-resolution microscopy, we show that botrocetin decreases the GPIb off-rate 2-fold in both human and mouse complexes without affecting the on-rate. The key to this behavior is that, upon binding of GPIb to vWF-A1, botrocetin prebound to vWF-A1 makes no contacts initially with GPIb, but subsequently slides around the A1 surface to form a new interface. This two-step mechanism and flexible coupling may prevent adverse alterations in on-rate of GPIb for vWF-A1, and permit adaptation to structural differences in GPIb and vWF in several prey species^ref.
=> jararhagin is a 55-kDa member of the metalloprotease-disintegrin family^ref
• jaracetin is a 60-kDa dimer representing a differently processed form of jararhagin^ref
• Bothrops moojeni has potent proteolytic and phospholipase A₂ activities^ref
=> bradykinin
• Calloselasma
• Calloselasma rhodostoma (Malayan pit viper)

=> aggretin, a heterodimeric C-type lectin, stimulates platelets by binding to a₂b₁ integrin and glycoprotein Ib, activating Syk and phospholipase Cg₂, but does not involve the glycoprotein VI/Fcg collagen receptor^{ref1, ref2}
=> rhodocytin / rhodocetin, a heterodimeric C-type lectin^ref
• Crotalus
• Crotalus atrox (a.k.a. western diamondback rattlesnake)

=> Ht-d : it acts as an hemorrhagic toxin
=> atrotoxin is an activator of voltage-gated Ca²⁺ channels
=> catrocollastatin, a protein which inhibits platelet adhesion to collagen^ref
• Crotalus durissus
• Crotalus durissus cumanensis
• Crotalus durissus terrificus (a.k.a South American rattlesnake, cascabel)

=> convulxin (CVX), a C-type lectin, binds to platelet GPVI^ref
=> crotoxin : it is made up of a phospholipase A₂ subunit (component B) and an acidic nonenzymatic subunit (component A) which enhances the toxicity of component A by preventing its nonspecific absorption. The output is reduction of ACh release.
=> crotamine : it opens voltage-gated Na⁺ channels
• Crotalus ruber
• Crotalus ruber ruber

=> hemorrhagic toxin 1 (HT1)
=> hemorrhagic toxin 2 (HT2)
They inhibitin platelet aggregation thanks to the disintegrin domain
• Crotalus scutulatus
• Crotalus scutulatus scutulatus (a.k.a. Mojave rattlesnake)

=> Mojave toxin (MoTX) : it is a PL-A₂ and a blocker of L-type voltage-gated Ca²⁺ channels
• Crotalus viridis
• Crotalus viridis helleri (southern Pacific rattlesnake)

=> STA-Staclot
• Crotalus viridis viridis (a.k.a. prairie rattlesnake)

=> viriditoxin : it causes hemorrhages
=> myotoxin a is a PL-A₂
California ground squirrels can recognize different predators and respond accordingly when giving warning calls to their fellows : when faced with an angry rattlesnake whip their tails threateningly back and forth to heat it and to warn the snake that they will not take an attack lying down. The squirrels achieve the effect by making their tail fur stand on end to expose more skin, and perhaps by dilating blood vessels near the tail's surface. The heat signal could function to distract the snake's attention from vulnerable young or simply as an indicator of the adult's presence. However, the squirrels are not entirely gung-ho; although rattlesnakes rarely eat adults, a fight could easily lead to death or serious injury. It is the first time that an animal has been shown to send a deliberate signal using infrared radiation. Rattlesnakes are a constant menace to the squirrels, often poaching young from families. This threat gives rise to aggressive stand-offs between snakes and adult squirrels, in which the rodent kicks sand and brandishes its tail in a bid to harass the predator into submission. The snakes do much of their hunting by detecting heat, using sensitive structures called pit organs in their faces. The new discovery shows that the squirrels take advantage of this sensitivity by broadcasting their message in a language the snakes can understand.
Web resources : American International Rattlesnake Museum
• Gloydius
• Gloydius halys (a.k.a. Agkistrodon halys, halys viper)
• Gloydius halys caraganus
=> agkistin is a snake venom metalloproteinase (SVMP)^ref
• Gloydius blomhoffi (a.k.a. Agkistrodon halys blomhoffii, Chinese Agkistrodon, mamushi)
• Gloydius blomhoffi brevicaudus
• Gloydius blomhoffi ssp.
• Gloydius blomhoffii siniticus
=> mamushigin binds to platelet glycoprotein Ib
=> acoagulatin, an anticoagulation factor^ref
• Protobothrops
• Protobothrops mucrosquamatus (a.k.a. Trimeresurus mucrosquamatus, Chinese habu, Taiwan habu)

=> mucrotoxin A
• Trimeresurus
• Trimeresurus albolabris (white-lipped tree viper)

=> alboaggregin A
=> alboaggregin B
Alboaggregin A induced platelet aggregation and release reaction with EC₅₀ = 10 and 30 nM, respectively, which is 20-fold lower than those for alboaggregin B. These observations suggest that the dimeric structure of alboaggregin B is sufficient to mediate its binding to GPIb and induce agglutination of platelets whereas aggregation and release reaction are significantly enhanced by tetrameric structure of alboaggregin A^ref.
=> alboluxin is a hexameric (alphabeta)3 snake C-type lectin which activates platelets via both GPIb and GPVI^ref.
=> alborhagin, is a metalloproteinase and an agonist at the platelet collagen receptor GPVIref
• Trimeresurus flavoviridis (a.k.a. habu snake, Protobothrops flavoviridis)

=> HR1A
=> HR1B
=> flavocetin-A is a strong platelet aggregation inhibitor which binds to glycoprotein Ib. The apparent molecular weight of flavocetin-A is 149 kDa. It consists of 2 subunits, a (17 kDa) and b (14 kDa)^ref
They act as hemorrhagic toxins by inhibitig platelet aggregation thanks to disintegrin domains.
=> factor IX/factor X-binding protein (IX/X-bp) is a disulfide-linked heterodimer consisting of homologous subunits A and B and binds predominantly to factor IX^ref.
• Trimeresurus stejnegeri

=> stejnulxin, a novel snake C-type lectin-like protein with potent platelet activating activity^ref
• Viperinae : snake bite mortality in Africa is estimated to be between 20-30,000 deaths annually. Systemic envenoming by Echis and Bitis vipers cause most of these deaths. Venom toxins common to these vipers include Zn metalloproteinases that induce bleeding by degradation of the vascular subendothelium and disintegrins that prevent platelet aggregation and blood clots to arrest bleeding.
• Bitis
• Bitis arietans (a.k.a. African puff adder)

=> bitiscetin, a platelet adhesion inducer, activates the binding of the von Willebrand factor (VWF) A1 domain to glycoprotein Ib (GPIb)^ref
• Bitis gabonica (a.k.a. Gaboon viper / adder)

=> Gaboon viper toxin is an inhibitor of voltage-gated K⁺ channels.
• Daboia
• Daboia russellii (a.k.a. Russell's viper)

Russell's viper venom (RVV)
=> RVV-X, the blood coagulation factor X activating enzyme (M_r 79,000), consists of a disulfide-bonded two-chain glycoprotein with a heavy chain of M_r 59,000 and a light chain of heterogeneous M_r 18,000 (LC₁) and 21,000 (LC₂).
=> daboiatoxin (DbTx) is a basic phospholipase A₂ (VRV-PL-VIIIa)
• Echis
• Echis carinatus (Indian saw-scaled viper)
• Echis carinatus leucogaster

=> carinactivase-1 (CA-1), consists of 2 subunits held together non-covalently but very tightly. One subunit is a 62-kDa polypeptide that has metalloprotease activity and is homologous to the single-chain enzyme ecarin; the other subunit of 25 kDa consists of two disulfide-linked polypeptides of 17 and 14 kDa, and this subunit resembles the anticoagulant in the habu snake venom, IX/X-bp, that specifically binds the Gla domains of coagulation factors IX and X in a Ca²⁺-dependent fashion. The activation of prothrombin by CA-1 requires Ca²⁺ ions at millimolar concentrations and in the absence of Ca²⁺ ions this enzyme is virtually inactive^ref
• Echis carinatus sochureki (a.k.a. Echis sochureki) is found in Indian subcontinent
=> echicetin
=> ecarin is a prothrombin activator^ref
• Echis multisquamatus

=> EMS16, a C-lectin type protein, a potent and selective inhibitor of the a₂b₁ integrin^ref
=> multactivase is a Ca²⁺-dependent prothrombin activator^ref
• Echis ocellatus

responsible for most of the 10-20,000 deaths that occur annually in West Africa. Toxin-specific antivenoms are likely to improve the efficacy of conventional antivenoms that are prepared from horses and sheep hyperimmunised with whole venom
=> cDNAs encoding a protein of 514 amino acids that shows 91% sequence similarity to ecarin
• Echis pyramidum leakeyi (a.k.a. Leakey's carpet viper, East African viper, Echis carinatus leakeyi) is found in East Africa

=> ecarin, a prothrombin-activating metalloproteinase that induces severe consumption coagulopathy.
=> toxins that cause bleeding (Zn metalloproteinases that degrade the vascular subendothelium) and inhibit blood clotting (disintegrins that bind to platelet integrins to prevent platelet aggregation)
=> phospholipase A₂^ref
• Gloydius
• Gloydius halys (a.k.a. halys viper, Agkistrodon halys pallas)

=> agkistrotoxin is a PL-A₂
• (a.k.a. Australian common brown snake)

=> textilotoxin : it blocks release of ACh
hemorrhagin unit : the amount of snake venom necessary to produce hemorrhages in the vascular network of a 3-day-old chick embryo
• coral or harlequin snakes
• Micruroides : a genus of venomous snakes of the family Elapidae
• Micrurus euryxanthus is the Arizona or Sonoran coral snake of Mexico and the Southwestern USA
• Micrurus : a genus of venomous snakes of the family Elapidae.
• Micrurus fulvius is the Southeastern or Texas coral snake, a species found in the southern United States and tropical America whose body is marked with bright red, yellow, and black bands
• brown snake : a venomous elapid snake of Australia and New Guinea belonging to the genus Demansia
• Colubridae (colubrids) : rear, immovable, grooved fangs
• Coluber constrictor (a.k.a. black racer or snake), a nonvenomous snake found in North America

• Snake Bites & Venom
• Ray Hunter's serpentology

• Venomous snake vaccinology : Self-immunization (Surviving snakebites) by Tim Friede, presented at the 5th World Congeress of Herpetology
• Kagen, S., Muthiah, R. Poisonous snake venom vaccination: a case report of a non-physician directed experiment. Annals of Allergy, Asthma and Immunology. Jan Vol 92. No 1 2004
• Burma (DMR), Russel's viper venoid. Tropical Med. and Hyg. 80, 423-425. 1986
• Calmette, A. Venoms. Trans by Ernest E.Austen, New York, 1908
• Cann, J. Snakes alive. E.C.O., 2001
• Carnochan, F, Adamson H. The empire of the snakes. Hutchinson and Co., 1935
• Crompton, J. The snake. Nick Lyons Books, 1963
• Klauber, L. Rattlesnakes. Univer of California Press, 1982
• Kursh, H. Cobras in his garden. Harvey House, Inc., 1965
• New, R., Theakston, RDG. Immunization against snake venoms. NEJM, 311(1), 56-57, 1984
• Sawai, Y., Kawamura, Y. Studies on the improvement of treatment on habu bites. The Japanese Journal of Experimental Medicine, 39(3), 197-203, 1969
• Webb, G., Powell, D. Henry Sewall. The John Hopkins Press, 1946
• Haast, W., Winer, M. Complete and spontaneous recovery from the bite of a blue krait snake. Am. J. of Trop.Med.and Hyg. 4, 1135-1137, 1955
• Wiener, S. Active immunization of man against the venom of the Australian tiger snake. Am.J.of Trop.Med.and Hyg. 9, 284-292, 1960
• National.Geographic Documentary, The tattooed snake clan

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