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Atheris chloroechis
General Details, Taxonomy and Biology, Venom, Clinical Effects, Treatment, First Aid , Antivenoms
Atheris chloroechis   ( West African Green Tree Viper )  [ Original photo copyright © Franck Principaud]
Family: Viperidae
Subfamily: Viperinae
Genus: Atheris
Species: chloroechis
Common Names
West African Green Tree Viper , Schlegel's Green Tree Viper , Western Bush Viper
Region
Sub-Saharan Africa
Countries
Benin, Cameroon, Cote d'Ivoire ( Ivory Coast ), Ghana, Guinea, Liberia, Nigeria, Sierra Leone, Togo
 
Taxonomy and Biology
Adult Length: 0.40 m
General Shape
Small in length, slightly compressed, slender bodied snake with a long prehensile tail. Can grow to a maximum of about 0.65 metres. Head is broad, flattened, triangular with keeled scales and distinct from narrow neck. Snout is broad and canthus is distinct. Eyes are moderately large in size with vertically elliptical pupils. Dorsal scales are small, imbricate, strongly keeled with apical pits, larger toward the vertebral line than laterally. Ventrals are smooth and rounded.
Habitat
Predominantly tropical rainforest and vine foliage but isolated records exist from semi-arid NE Nigeria.
Habits
Diurnal and arboreal snake. Tends to take shelter in shrubs and foliage up to about 2 metres from ground level.
Prey
Feeds mainly on lizards, frogs, small rodents and small mammals.
Species Map
Small (Approx 20k) version
 
Venom
General: Venom Neurotoxins
Probably not present
General: Venom Myotoxins
Probably not present
General: Venom Procoagulants
Present but not defined
General: Venom Anticoagulants
Probably not present
General: Venom Haemorrhagins
Possibly present
General: Venom Nephrotoxins
Probably not present
General: Venom Cardiotoxins
Unknown
General: Venom Necrotoxins
Probably not present
General: Venom Other
Unknown
 
Clinical Effects
General: Dangerousness
Severe envenoming possible, potentially lethal
General: Rate of Envenoming: Unknown
General: Untreated Lethality Rate: Unknown but may cause major envenoming
General: Local Effects
Local pain, swelling, bruising & blistering
General: Local Necrosis
Does not occur, based on current clinical evidence
General: General Systemic Effects
Variable non-specific effects which may include headache, nausea, vomiting, abdominal pain, diarrhoea, tachypnoea, respiratory distress, hypotension, dizziness, collapse or convulsions
General: Neurotoxic Paralysis
Does not occur, based on current clinical evidence
General: Myotoxicity
Does not occur, based on current clinical evidence
General: Coagulopathy & Haemorrhages
Uncommon to rare, but may be moderate to severe coagulopathy
General: Renal Damage
Uncommon to rare, usually secondary effect
General: Cardiotoxicity
Does not occur, based on current clinical evidence
General: Other
Unknown
 
First Aid
Description: First aid for bites by Viperid snakes likely to cause significant local injury at the bite site (see listing in Comments section).
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.
 
Treatment
Treatment Summary
Most bites minor, but at least some Atheris species can cause major systemic envenoming, with severe local swelling, shock, coagulopathy, bleeding, renal damage. No antivenom is available, so treatment is symptomatic, supportive, and if severe coagulopathy, consider factor replacement.
Key Diagnostic Features
Local pain, swelling + coagulopathy & haemorrhage
General Approach to Management
While most cases will be minor, not requiring admission, some cases will be more severe, requiring admission and treatment, so assess carefully before early discharge.
Antivenom Therapy
No antivenom available
Antivenoms
No Antivenoms
Atheris chloroechis ( West African Green Tree Viper ) [ Original photo copyright © Franck Principaud]
Larger version
 
Atheris chloroechis ( West African Green Tree Viper ) [ Original photo copyright © Franck Principaud]
Larger version
 
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