Bitis rhinoceros
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Family: Viperidae
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Subfamily: Viperinae
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Genus: Bitis
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Species: rhinoceros
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Common Names
West African Gaboon Viper , Gaboon Adder , Gaboon Viper ( Western Race ) , West African Gaboon Viper.
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Region
Sub-Saharan Africa
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Countries
Cote d'Ivoire ( Ivory Coast ), Gambia, Ghana, Guinea, Guinea-Bissau, Liberia, Senegal, Sierra Leone
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Taxonomy and Biology
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Adult Length: 1.20 m
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General Shape
Large, slightly depressed, extremely thick and heavy bodied ( fat ) snake with a short tail. Can grow to a maximum of about 2.37 metres. Head is broad, flat and triangular and very distinct from narrow neck. Snout is short with a pair of triangular nasal horns and canthus is distinct. Eyes are medium in size with vertically elliptical pupils. Dorsal scales are keeled with apical pits. Large fangs up to about 5.5 centimetres in length.
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Habitat
Rainforest, secondary forest and forest fringes up to about 2000 metres.
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Habits
Terrestrial, often found in leaf litter where its colour and pattern provide excellent camouflage. Although usually appearing fat and lazy it captures prey by ambush and strikes rapidly. If confronted will huff and puff a lot, but rarely bites. Most bites occur from accidentally stepping on it.
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Prey
Feeds mainly on large rodents and ground birds but will eat a variety of prey including amphibians and larger mammals.
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Venom
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General: Venom Neurotoxins
Not present (based on research on related species)
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General: Venom Myotoxins
Not present (based on research on related species)
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General: Venom Procoagulants
Fibrinogenases (based on research on related species)
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General: Venom Anticoagulants
Possibly present (based on research on related species)
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General: Venom Haemorrhagins
Zinc metalloproteinase (based on research on related species)
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General: Venom Nephrotoxins
Not present (based on research on related species)
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General: Venom Cardiotoxins
Present but not defined (based on research on related species)
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General: Venom Necrotoxins
Possibly present (based on research on related species)
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General: Venom Other
Unknown
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Clinical Effects
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General: Dangerousness
Severe envenoming likely, high lethality potential
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General: Rate of Envenoming: 60-80% (estimate only)
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General: Untreated Lethality Rate: Unknown but probably high
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General: Local Effects
Marked local effects; pain, severe swelling, bruising, blistering
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General: Local Necrosis
Common, moderate to severe
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General: General Systemic Effects
Variable non-specific effects which may include headache, nausea, vomiting, abdominal pain, diarrhoea, dizziness, collapse or convulsions
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General: Neurotoxic Paralysis
Only minor neurotoxicity reported
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General: Myotoxicity
Not reported, unlikely to be significant
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General: Coagulopathy & Haemorrhages
Very common, coagulopathy + haemorrhagins causing bleeding is major clinical effect
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General: Renal Damage
Uncommon to rare, usually secondary effect
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General: Cardiotoxicity
Common, cardiotoxicity is major clinical effect
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General: Other
Shock secondary to fluid shifts due to local tissue injury is likely in severe cases
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First Aid
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Description: First aid for bites by Viperid snakes likely to cause significant local injury at the bite site (see listing in Comments section).
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Details
1. After ensuring the patient and onlookers have moved out of range of further strikes by the snake, the bitten person should be reassured and persuaded to lie down and remain still. Many will be terrified, fearing sudden death and, in this mood, they may behave irrationally or even hysterically. The basis for reassurance is the fact that many venomous bites do not result in envenoming, the relatively slow progression to severe envenoming (hours following elapid bites, days following viper bites) and the effectiveness of modern medical treatment. 2. The bite wound should not be tampered with in any way. Wiping it once with a damp cloth to remove surface venom is unlikely to do much harm (or good) but the wound must not be massaged. 3. All rings or other jewellery on the bitten limb, especially on fingers, should be removed, as they may act as tourniquets if oedema develops. 4. The bitten limb should be immobilised as effectively as possible using an extemporised splint or sling; if available, crepe bandaging of the splinted limb is an effective form of immobilisation. 5. If there is any impairment of vital functions, such as problems with respiration, airway, circulation, heart function, these must be supported as a priority. In particular, for bites causing flaccid paralysis, including respiratory paralysis, both airway and respiration may be impaired, requiring urgent and prolonged treatment, which may include the mouth to mask (mouth to mouth) technique of expired air transfer. Seek urgent medical attention. 6. Do not use Tourniquets, cut, suck or scarify the wound or apply chemicals or electric shock. 7. Avoid peroral intake, absolutely no alcohol. No sedatives outside hospital. If there will be considerable delay before reaching medical aid, measured in several hours to days, then give clear fluids by mouth to prevent dehydration. 8. If the offending snake has been killed it should be brought with the patient for identification (only relevant in areas where there are more than one naturally occurring venomous snake species), but be careful to avoid touching the head, as even a dead snake can envenom. No attempt should be made to pursue the snake into the undergrowth as this will risk further bites. 9. The snakebite victim should be transported as quickly and as passively as possible to the nearest place where they can be seen by a medically-trained person (health station, dispensary, clinic or hospital). The bitten limb must not be exercised as muscular contraction will promote systemic absorption of venom. If no motor vehicle or boat is available, the patient can be carried on a stretcher or hurdle, on the pillion or crossbar of a bicycle or on someone's back. 10. Most traditional, and many of the more recently fashionable, first aid measures are useless and potentially dangerous. These include local cauterization, incision, excision, amputation, suction by mouth, vacuum pump or syringe, combined incision and suction ("venom-ex" apparatus), injection or instillation of compounds such as potassium permanganate, phenol (carbolic soap) and trypsin, application of electric shocks or ice (cryotherapy), use of traditional herbal, folk and other remedies including the ingestion of emetic plant products and parts of the snake, multiple incisions, tattooing and so on.
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Treatment
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Treatment Summary
Gaboon viper bites are likely to cause severe local & systemic envenoming rapidly, requiring urgent assessment & treatment. Fluid shift & shock may occur. Urgent fluid load, good wound care and antivenom are required. Antivenom is vital to treat major systemic effects. While compartment syndrome can occur, it must be confirmed by pressure measurement before considering fasciotomy. Beware any surgical intervention while venom haemorrhagins are active.
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Key Diagnostic Features
Local swelling, blistering, necrosis + coagulopathy, bleeding, cardiotoxicity
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General Approach to Management
All cases should be treated as urgent & potentially lethal. Rapid assessment & commencement of treatment including appropriate antivenom (if indicated & available) is mandatory. Admit all cases.
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Antivenom Therapy
Antivenom is the key treatment for systemic envenoming. Multiple doses may be required.
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1. Antivenom Code: SAfSAI03
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Antivenom Name: SAIMR Polyvalent Antivenom
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Manufacturer: South African Vaccine Producers (Pty) Ltd
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Phone: +27 11 386-6000; +27 11 386-6078
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Address: Postal address PO Box 28999 Sandringham 2131 Gauteng Province
Physical address 1 Modderfontein Road Sandringham, Johannesburg
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Country: South Africa
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2. Antivenom Code: SAfAVC02
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Antivenom Name: Polyvalent Snake Antivenom
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Manufacturer: National Antivenom and Vaccine Production Centre
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Phone: ++966-1-252-0088 ext 45626, 45637.
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Address: P.O. Box 22490 Riyadh 11426
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Country: Saudi Arabia
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3. Antivenom Code: SAfSII03
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Antivenom Name: SII Polyvalent Antisnake Venom Serum ( lyophilized ) ( Central Africa )
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Manufacturer: Serum Institute of India Ltd.
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Phone: +91-20-26993900
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Address: 212/2, Hadapsar, Off Soli Poonawalla Road, Pune-411042. India
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Country: India
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4. Antivenom Code: SAfIBM01
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Antivenom Name: Antivipmyn Africa
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Manufacturer: Instituto Bioclon
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Phone: ++56-65-41-11
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Address: Calzada de Tlalpan No. 4687 Toriello Guerra C.P. 14050 Mexico, D.F.,
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Country: Mexico
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5. Antivenom Code: SAfSPF02
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Antivenom Name: FAV-Afrique
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Manufacturer: Sanofi-Pasteur
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Phone: +33 (0)4 37 37 01 00
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Address: 2, Avenue Pont Pasteur, CEDEX 07, Lyon 69367
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Country: France
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Images
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Bitis rhinoceros ( West African Gaboon Viper ) [ Original photo copyright © Dr Julian White ]
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Bitis rhinoceros ( West African Gaboon Viper ) [ Original photo copyright © Dr Julian White ]
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Bitis rhinoceros ( West African Gaboon Viper ) [ Original photo copyright © Dr Jurg Meier ]
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Bitis rhinoceros ( West African Gaboon Viper ) [ Original photo copyright © Dr Julian White ]
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Bitis rhinoceros ( West African Gaboon Viper ) [ Original photo copyright © Franck Principaud]
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Bitis rhinoceros ( West African Gaboon Viper ) [ Original photo copyright © Franck Principaud]
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