![Thelotornis kirtlandi ( Forest Twig Snake ) [ Original photo copyright © Dr Julian White ]](images/snakes/SNP01341.jpg)
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Family: Colubridae
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Subfamily: Colubrinae
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Genus: Thelotornis
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Species: kirtlandi
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Common Names
Forest Twig Snake , Forest Bird Snake , Forest Vine Snake , Green Headed Vine Snake
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Local Names
Ivissi , Gewone Voelslang , Ngasihiri , Mbeya , Singa
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Region
Sub-Saharan Africa
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Countries
Angola, Benin, Burundi, Cameroon, Central African Republic, Democratic Republic of Congo, Republic of Congo, Cote d'Ivoire ( Ivory Coast ), Equatorial Guinea, Gabon, Ghana, Guinea, Guinea-Bissau, Liberia, Nigeria, Rwanda, Sierra Leone, Tanzania, Togo, Uganda, Cabinda
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Taxonomy and Biology
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Adult Length: 1.10 m
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General Shape
Medium in length, cylindrical, exceptionally slender bodied snake with an extremely long and slender tail. Can grow to a maximum of about 1.71 metres. Head is elongate, flattened, lance shaped when viewed from above and distinct from slender neck. Snout is long with a distinct and projecting canthus which forms a shallow groove below it on the side of the snout. Eyes are pale, large in size with horizontally elliptical pupils ( keyhole shaped ). Tongue is bright red with a black tip. Dorsal scales are arranged obliquely and feebly keeled with apical pits. Dorsal scale count usually ( 19 or 21 ) - 19 ( 17 ) - 13.
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Habitat
Rainforest, forest, dense woodland and reed beds. Particularly common near natural glades and around farms within forests. Also found in parks and gardens in forest towns.
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Habits
Arboreal, living in trees, bushes, thickets reed beds etc. and diurnal. Although an excellent climber it is seldom found high in trees, preferring to remain on lower branches. It will descend to the ground to pursue prey and moves rapidly on the ground. Mild disposition. It will inflate its neck and expose a series of black and bluish grey bars or blotches on the throat if molested and can move swiftly if threatened. They often remain motionless in trees, except to sway slowly back and forth ( imitating a branch being blown by the wind ) awaiting prey for extended periods of time. Prey is killed by a swift strike, holding the prey in the jaws and a chewing motion to inject the venom until the prey succumbs. It eats arboreal prey while hanging downwards and pulling the prey upwards.
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Prey
Rely on their colouration ( camouflage ) and slow movement to ambush mainly small lizards ( particularly geckos, agamids and chameleons ) and birds. Although arboreal, it will also ambush suitable ground dwelling prey by dropping from a branch to the ground and pursuing them.
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Venom
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General: Venom Neurotoxins
Not present
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General: Venom Myotoxins
Not present
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General: Venom Procoagulants
Mixture of procoagulants
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General: Venom Anticoagulants
Possibly present
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General: Venom Haemorrhagins
Possibly present
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General: Venom Nephrotoxins
Secondary nephrotoxicity only
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General: Venom Cardiotoxins
Not present
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General: Venom Necrotoxins
Not present
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General: Venom Other
Not present or not significant
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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 but likely to be moderate
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General: Untreated Lethality Rate: Unknown but has caused deaths
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General: Local Effects
Local pain only
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General: Local Necrosis
Not likely to occur
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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
Unlikely to occur
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General: Myotoxicity
Not likely to occur
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General: Coagulopathy & Haemorrhages
Uncommon to rare, but may be moderate to severe coagulopathy
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General: Renal Damage
Recognised complication, usually secondary to coagulopathy
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General: Cardiotoxicity
Insufficient clinical reports to know
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General: Other
Not likely to occur
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First Aid
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Description: First aid for potentially dangerous non-front-fanged colubroid snakes (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. If the bite is on a limb, a broad bandage (even torn strips of clothing or pantyhose) should be applied over the bitten area at moderate pressure (as for a sprain; not so tight circulation is impaired), then extended to cover as much of the bitten limb as possible, including fingers or toes, going over the top of clothing rather than risking excessive limb movement by removing clothing. The bitten limb should then be immobilised as effectively as possible using an extemporised splint or sling.
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. In Australia and parts of New Guinea, Snake Venom Detection Kits are available to identify the snake from venom left on the skin.
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
Bites cause potentially severe, even lethal coagulopathy and require urgent assessment & treatment. Antivenom, though often difficult to obtain, is the most effective treatment for the coagulopathy by the related boomslang, but effectiveness for Thelotornis envenoming is not established and it should be used only with great caution, in severe cases.
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Key Diagnostic Features
Local pain, swelling + coagulopathy & haemorrhage
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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
Only antivenoms available are for related species, but should be considered for significant envenoming, if more conservative treatment is unsuccessful. There is no guarantee SAVP Boomslang Antivenom will have any beneficial effect for Thelotornis bites, but it remains the only product raised against even a vaguely related species. In considering whether to use this product, carefully weigh up the risks versus uncertain benefit. This is not an approved use for this antivenom, based on the producers guidelines.
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