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Enhydrina schistosa
General Details, Taxonomy and Biology, Venom, Clinical Effects, Treatment, First Aid , Antivenoms
Family: Elapidae
Subfamily: Hydrophiinae
Genus: Enhydrina
Species: schistosa
Common Names
Beaked Sea Snake , Hook-nosed Sea Snake , Common Sea Snake , Valakadyn Sea Snake
Local Names
Valakkadiya , Valakkadiyan
Australia, Bahrain, Bangladesh, Brunei, Cambodia, China, Indonesia, India, Iran, Kuwait, Malaysia, Myanmar, Oman, Pakistan, Papua New Guinea, Qatar, Saudi Arabia, Singapore, Sri Lanka, United Arab Emirates, Vietnam
Taxonomy and Biology
Adult Length: 0.80 m
General Shape
Medium in length, moderately stout bodied seasnake with a moderately slender and elongate neck and forebody, with stronger built, but elongate, mid and posterior body. Tail is compressed laterally. Can grow to a maximum of about 1.58 metres. Head elongate and slightly distinct from neck with a distinctive curved snout resulting in a beaked appearance. Eyes are medium in size with round pupils. The lower jaw skin is very extensible. Nostril located on snout dorsum. Dorsal scales are imbricate and weakly keeled. Ventrals barely wider than adjacent dorsal scales. About 40 to 55 scale rows around the neck. Preanals feebly enlarged.
Marine : Shallow bays and estuaries.
Easily angered and quite aggressive. Active by both day and night.
Feeds mainly on catfish, prawns and other fish species.
Species Map
Small (Approx 20k) version
Average Venom Qty
7 to 20 mg ( dry weight ), U.S. Dept. Navy (1968) ( Ref : R000914 ).

8 mg ( dry weight ), Brown (1973) ( Ref : R000681 ).

8.50 mg, Reid (1975) ( Ref : R000525).

10 to 15 mg ( dry weight ), Minton (1974) ( Ref : R000504 ).
Preferred LD50 Estimate
0.164 mg / kg sc ( mice ), Broad et al (1979) ( Ref : R000006 ) in Gopalakrishnakone P. and Chou L. M. (1990) ( Ref : R000004 ).
General: Venom Neurotoxins
Postsynaptic neurotoxins
General: Venom Myotoxins
Systemic myotoxins present
General: Venom Procoagulants
Not present
General: Venom Anticoagulants
Not present
General: Venom Haemorrhagins
Not present
General: Venom Nephrotoxins
Secondary nephrotoxicity only
General: Venom Cardiotoxins
Secondary cardiotoxicity only
General: Venom Necrotoxins
Not present
General: Venom Other
Not present or not significant
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
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
Uncommon to rare, but potentially moderate to severe flaccid paralysis
General: Myotoxicity
Common, usually moderate to severe
General: Coagulopathy & Haemorrhages
Unlikely to occur
General: Renal Damage
Recognised complication, usually secondary to myolysis
General: Cardiotoxicity
Uncommon, secondary to myolysis-induced hyperkalaemia
General: Other
Insufficient clinical reports to know
First Aid
Description: First aid for bites by Elapid snakes which do not cause significant injury at the bite site (see Comments for partial listing), but which may have the potential to cause significant general (systemic) effects, such as paralysis, muscle damage, or bleeding.
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. For Australian snakes only, do not wash or clean the wound in any way, as this may interfere with later venom detection once in a hospital.
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 Summary
Sea snake bites vary from trivial to lethal envenoming, so urgently assess all cases, looking especially for paralysis and/or myolysis. These usually develop in first 6 hrs. They require good hydration/renal flow, respiratory support (for respiratory paralysis), IV antivenom (CSL Sea Snake AV).
Key Diagnostic Features
Minimal local pain, development over several hours of flaccid paralysis and/or myolysis
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
Antivenom is the key treatment for systemic envenoming. Multiple doses may be required.
1. Antivenom Code: MAuCSL03
Antivenom Name: Sea snake antivenom
Manufacturer: CSL Limited
Phone: ++61-3-9389-1911
Toll free: 1800 642 865
Address: 45 Poplar Road
Victoria 3052
Country: Australia
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