![Atheris squamigera ( Hallowell's Green Tree Viper ) subsp. squamigera[ Original photo copyright © Dr Julian White ]](images/snakes/SNP01981.jpg)
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Family: Viperidae
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Subfamily: Viperinae
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Genus: Atheris
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Species: squamigera
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Subspecies: squamigera
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Common Names
( subsp. squamigera ) Hallowell's Green Tree Viper , Hallowell's Bush Viper , Green Bush Viper , Variable Bush Viper , Leaf Viper , African Bush Viper , Rough-scaled Bush Viper
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Local Names
Douer , Kisigosogo , Kiyozima , Muryankunga , Nalukonge
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Region
Sub-Saharan Africa
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Countries
Angola, Benin, Cameroon, Central African Republic, Democratic Republic of Congo, Republic of Congo, Equatorial Guinea, Gabon, Ghana, Kenya, Nigeria, Togo, Uganda, Cabinda
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Taxonomy and Biology
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Adult Length: 0.45 m
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General Shape
Small in length, slightly compressed, relatively slender bodied snake with a relatively long prehensile tail. Can grow to a maximum of about 0.80 metres. Head is broad, flat, covered with strongly keeled overlapping scales and distinct from narrow neck. Snout is broad and canthus is distinct. Eyes are moderately large in size with vertically elliptical pupils. Mouth is unusually large. Dorsal scales are strongly keeled with apical pits and dorsal scales tend to be larger toward the vertebral line than laterally. Ventrals are rounded. Dorsal scale count usually ( 19 to 23 ) - ( 19 to 23 ) - ( 15 to 19 )
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Habitat
Tropical rainforest and forest edges.
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Habits
Arboreal and mainly nocturnal ( often basks in the sun on top of vegetation in clearings during the day ). Often found up to about 6 metres above ground. It usually hangs head down and loosely coiled on a branch ready to ambush prey, but will descend to ground level to search for prey. It has a reputation for being easily angered and ill-tempered and will strike readily if threatened.
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Prey
Feeds mainly on small rodents, but will eat lizards, frogs and other snakes.
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Venom
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General: Venom Neurotoxins
Probably not present
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General: Venom Myotoxins
Probably not present
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General: Venom Procoagulants
Present but not defined
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General: Venom Anticoagulants
Probably not present
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General: Venom Haemorrhagins
Possibly present
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General: Venom Nephrotoxins
Probably not present
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General: Venom Cardiotoxins
Unknown
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General: Venom Necrotoxins
Probably not present
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General: Venom Other
Unknown
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Clinical Effects
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General: Dangerousness
Severe envenoming possible, potentially lethal
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General: Rate of Envenoming: Unknown
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General: Untreated Lethality Rate: Unknown but may cause major envenoming
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General: Local Effects
Local pain, swelling, bruising & blistering
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General: Local Necrosis
Does not occur, based on current clinical evidence
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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
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General: Neurotoxic Paralysis
Does not occur, based on current clinical evidence
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General: Myotoxicity
Does not occur, based on current clinical evidence
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General: Coagulopathy & Haemorrhages
Uncommon to rare, but may be moderate to severe coagulopathy
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General: Renal Damage
Uncommon to rare, usually secondary effect
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General: Cardiotoxicity
Does not occur, based on current clinical evidence
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General: Other
Unknown
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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
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.
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Key Diagnostic Features
Local pain, swelling + coagulopathy & haemorrhage
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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.
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Antivenom Therapy
No antivenom available
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