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Boiga trigonata
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Family: Colubridae
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Subfamily: Colubrinae
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Genus: Boiga
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Species: trigonata
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Subspecies: trigonata , melanocephala
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Common Names
Gamma Cat Snake , Common Cat Snake , Plum-head , Indian Gamma Snake , Dark-Headed Gamma Snake ( B. t. trigonata ) , Common Indian Cat Snake
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Local Names
Ran Mapila
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Region
West Asia + Indian Sub-continent + Southeast Asia
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Countries
Afghanistan, Bangladesh, India, Iran, Nepal, Pakistan, Sri Lanka, Tajikistan, Turkmenistan, Uzbekistan
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Taxonomy and Biology
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Adult Length: 0.65 m
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General Shape
Small to medium length, slightly laterally compressed, moderately slender to medium bodied snake with a short tail. Can grow to a maximum of about 1.24 metres. Head is sub-triangular, flat and distinct from neck. Snout is short. Eyes large in size, slightly protruding with vertically elliptical pupils. Dorsal scales are smooth with single apical pits and strongly diagonally aligned and narrowing laterally. Vertebral scale row is feebly enlarged. Ventrals are laterally angulate. Dorsal scale count 21 ( 23 ) - 21 ( 19 to 23 ) - 15 ( 13 to 17 ).
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Habitat
Mainly found in arid and semiarid regions including deserts and rocky terrain with soft sand in west Asia, but more vegetated regions on the Indian subcontinent including gallery forest.
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Habits
Mainly nocturnal and arboreal. Found most often in shrubs and small trees and when at rest tends to lay coiled on branches rather than extended along branches. Tend to shake their tail and go on the offensive if disturbed and quick to strike when threatened or provoked. They kill their prey by constriction.
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Prey
Feeds mainly on lizards, birds and their eggs and small mammals.
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Venom
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General: Venom Neurotoxins
Non-venomous
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General: Venom Myotoxins
Non-venomous
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General: Venom Procoagulants
Non-venomous
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General: Venom Anticoagulants
Non-venomous
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General: Venom Haemorrhagins
Non-venomous
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General: Venom Nephrotoxins
Non-venomous
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General: Venom Cardiotoxins
Non-venomous
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General: Venom Necrotoxins
Non-venomous
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General: Venom Other
Non-venomous
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Clinical Effects
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General: Dangerousness
Non-venomous, so no likelihood of envenoming or lethality
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General: Rate of Envenoming: Non-venomous, so essentially all bites should be "dry".
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General: Untreated Lethality Rate: Non-venomous, so no likelihood of envenoming or lethality
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General: Local Effects
Mild to moderate local effects possible
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General: Local Necrosis
Not likely to occur
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General: General Systemic Effects
General systemic effects unlikely
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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
Does not occur, based on current clinical evidence
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General: Renal Damage
Does not occur, based on current clinical evidence
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General: Cardiotoxicity
Does not occur, based on current clinical evidence
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General: Other
Not likely to occur
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First Aid
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Description: First aid for bites by non-front-fanged colubroid snakes likely to cause either no effects or only mild local effects.
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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.
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
Bites by this species are not expected to cause medically significant effects and the only risk, probably small, is local secondary infection. Patients presenting with bites by these snakes do not require medical attention, other than to check for infection and ensure tetanus immune status. Patients should be advised to return if local symptoms develop, suggesting secondary infection.
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Key Diagnostic Features
Bites unlikely to cause more than mild to moderate local swelling & pain, occasionally local bruising, paresthesia/numbness, erythema or bleeding, but no necrosis and no systemic effects.
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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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Images
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No images for Images
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