Saturday, March 4, 2017

Cambodia - Very Venomous Snakes Found - Bungarus candidus

Bungarus candidus ( Malayan Krait ) 
Original photo copyright © Dr Julian White










Family: Elapidae

Subfamily: Elapinae

Genus: Bungarus

Species: candidus

Common Names: Malayan Krait , Common Krait , Blue Krait , Javan Krait

Local Names: Ular Katang Tebu , Ular Weling , Oraj Weling

Region : Southeast Asia

Countries : Cambodia, Indonesia, Laos, Malaysia, Myanmar, Singapore, Thailand, Vietnam

Taxonomy and Biology

Adult Length: 0.80 m

General Shape: Medium in length, slender, cylindrical bodied snake with a short tail ending in a sharp tip. Can grow to a maximum of about 1.60 metres. Head is flat and slightly distinct from neck. Eyes are small in size and black with a barely visible, round pupils. Nostrils are large. Dorsal scales are smooth and glossy with the vertebral row enlarged and hexagonal. Dorsal scale count 15 ( 17 ) - 15 - 15.

Habitat: Lowland hilly primary and secondary wet forest at elevations usually up to about 1600 metres. Rarely found in human habitations.

Habits: Nocturnal and terrestrial snake with an inoffensive disposition. When disturbed it coils loosely and hides its head beneath its body. Reluctant to bite except upon persistent provocation.

Prey: Feeds mainly on snakes, but will occasionally feed on small mammals, lizards and frogs.


Bungarus candidus ( Malayan Krait ) Original photo copyright © Dr Wolfgang Wuster

Venom

General: Venom Neurotoxins
Pre- & Post-synaptic neurotoxins
General: Venom Myotoxins
Not present
General: Venom Procoagulants
Not present
General: Venom Anticoagulants
Not present
General: Venom Haemorrhagins
Not present
General: Venom Nephrotoxins
Not present
General: Venom Cardiotoxins
Not present
General: Venom Necrotoxins
Not present
General: Venom Other
Not present or not significant

Clinical Effects

General: Dangerousness
Severe envenoming likely, high lethality potential
General: Rate of Envenoming
Unknown but likely to be high
General: Untreated Lethality Rate
60-70%
General: Local Effects
None or minimal
General: Local Necrosis
Not likely to occur
General: General Systemic Effects
Variable non-specific effects which may include headache, nausea, vomiting, abdominal pain, diarrhoea, dizziness, collapse or convulsions
General: Neurotoxic Paralysis
Very common, flaccid paralysis is major clinical effect
General: Myotoxicity
Not likely to occur
General: Coagulopathy & Haemorrhages
Unlikely to occur
General: Renal Damage
Unlikely to occur
General: Cardiotoxicity
Unlikely to occur
General: Other
Not likely to occur

First Aid

Description: First aid for bites by Elapid snakes which do not cause significant injury at the bite site, but which may have the potential to cause significant general (systemic) effects, such as paralysis, muscle damage, or bleeding.

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.

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
Krait bites can cause moderate to severe flaccid paralysis, respiratory failure, requiring intubation & ventilation in severe cases. Antivenom available for major species, may prevent worsening of paralysis, but may not reverse established paralysis.

Key Diagnostic Features
Minimal to mild local reaction + flaccid paralysis

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.
Antivenom Therapy

Only antivenoms available are for related species, but should be used for significant envenoming

Antivenoms

1. Antivenom Code: SAsTRC04
Antivenom Name: Banded Krait Antivenin
Manufacturer: Science Division, Thai Red Cross Society
Phone: ++66-2-252-0161 (up to 0164)
Address: Queen Saovabha Memorial Institute
1871 Rama IV Road
Pathumwan
Bangkok 10330
Country: Thailand

2. Antivenom Code: SAsVRU03
Antivenom Name: Bungarus candidus Antivenom
Manufacturer: Venom Research Unit
Address: University of Medicine and Pharmacy
Ho Chi Minh City
217 An Duong Vuong Q5

Country: Vietnam

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