Daboia siamensis ( Eastern Russell's Viper )
Original photo copyright © Dr Julian White
Family: Viperidae
Subfamily: Viperinae
Genus: Daboia
Species: siamensis
Common Names: Eastern Russell's Viper , Daboia ,
Tic-Polonga , Siamese Russell's Viper , Seven Pacer , Chain Snake
Local Names: Mwe Pwe , Yuan Ban Kui , Souah-chuwah
Region: Southeast Asia + North Asia
Countries: Cambodia, China, Indonesia,
Laos, Myanmar, Taiwan, Thailand, Vietnam
Daboia siamensis ( Eastern Russell's Viper ) Original photo copyright © Dr Julian White
Taxonomy and Biology
Adult Length: 1.00 m
General Shape: Medium in length, heavy and stout
bodied, dorsoventrally flattened snake with short a tail. Can grow to a maximum
of about 1.70 metres. Head is large, flat, bluntly pointed ( snout is bluntly
rounded and broad ), broadly triangular and distinct from neck with strongly
keeled scales and large nostrils. Canthus is distinct. Eyes are medium to
moderately large in size with vertically elliptical pupils. Dorsal scales are
strongly keeled ( except a smooth 1st dorsal scale row ). Dorsal scale count (
25 to 31 ) - 29 ( 27 - 33 ) - ( 21 to 23 ).
Habitat: Frequently encountered in paddy fields and
other agricultural land at elevations below 1000 metres, but may be found in a
wide variety of terrain including coastal plains, wooded regions and
particularly open, rocky, bushy or grassland regions, hills and mountain
foothills up to about 2000 metres. More abundant in open lowland plains and
avoids dense jungle terrain.
Habits: Nocturnal and most active during early
evening. Captures prey by ambush. If disturbed, it tends to hold its ground
rather than flee, hisses loudly and assumes a striking position with a lateral
S-shaped loop of the neck. If it strikes it does so with force inflicting a
deep bite.
Prey: Feeds mainly on rodents, lizards and frogs.
Daboia siamensis ( Eastern Russell's Viper ) Original photo copyright © Dr Wolfgang Wuster
Venom
General: Venom Neurotoxins
|
Probably not present
|
General: Venom Myotoxins
|
Probably not present
|
General: Venom Procoagulants
|
Mixture of procoagulants
|
General: Venom Anticoagulants
|
Possibly present
|
General: Venom Haemorrhagins
|
Zinc metalloproteinase
|
General: Venom Nephrotoxins
|
Possibly present
|
General: Venom Cardiotoxins
|
Probably not present
|
General: Venom Necrotoxins
|
Possibly present
|
General: Venom Other
|
Unknown
|
Daboia siamensis ( Eastern Russell's Viper ) Battanbang, Cambodia Original photo copyright © David Williams
Clinical Effects
General: Dangerousness
|
Severe envenoming likely, high lethality potential
|
General: Rate of Envenoming
|
>80%
|
General: Untreated Lethality Rate
|
10-20%
|
General: Local Effects
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Marked local effects; pain, severe swelling, bruising,
blistering, necrosis
|
General: Local Necrosis
|
Uncommon but can be moderate to severe
|
General: General Systemic Effects
|
Variable non-specific effects which may include headache,
nausea, vomiting, abdominal pain, diarrhoea, dizziness, collapse or
convulsions
|
General: Neurotoxic Paralysis
|
No clinical reports for this species, but related
subspecies cause mild flaccid paralysis (ptosis & ophthalmoplegia)
|
General: Myotoxicity
|
No case reports for this species, but related subspecies
can cause systemic myolysis
|
General: Coagulopathy & Haemorrhages
|
Very common, coagulopathy + haemorrhagins causing bleeding
is major clinical effect
|
General: Renal Damage
|
Common, renal failure is major clinical effect
|
General: Cardiotoxicity
|
Rare, usually secondary
|
General: Other
|
Shock secondary to fluid shifts due to local tissue
injury is possible in severe cases. Anterior pituitary haemorrhage with
panhypopituitarism can occur in bites by Burmese Russell's vipers
|
First Aid
Description:
First aid
for bites by Viperid snakes likely to cause significant local injury at the
bite site.
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.
Treatment
Treatment Summary: Bites by Russell's
vipers cause severe, potentially lethal envenoming, requiring urgent assessment
& treatment with IV fluids, IV antivenom and good wound care.
Key Diagnostic Features: Local pain, swelling,
blistering, necrosis + coagulopathy, bleeding, renal failure, rarely anterior
pituitary haemorrhage with panhypopituitarism.
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.
Antivenoms
1.
Antivenom Code: SAsTRC05
Antivenom
Name: Russell's Viper 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: SAsGPO02
Antivenom
Name: Russell's Viper Antivenom
Manufacturer:
Thai Government Pharmaceutical Organisation
Phone:
++662-644-8851
Address:
75/1 Rama VI Road,
Ratchathewi
Bangkok
10400,
Country:
Thailand
3.
Antivenom Code: SAsVRU05
Antivenom
Name: Naja siamensis Antivenom
Manufacturer:
Venom Research Unit
Address:
University of Medicine and Pharmacy
Ho Chi
Minh City
217 An
Duong Vuong Q5
Country:
Vietnam
4.
Antivenom Code: SAsPIM01
Antivenom
Name: Bivalent
Manufacturer:
Pharmaceutical Industries Corporation
Phone:
+95-1-566742
+95-1-566750
Address:
192 Kaba Aye Pagoda Road,
Bahan,
Yangon,
Country:
Myanmar ( Burma )
5.
Antivenom Code: SAsPIM03
Antivenom
Name: Anti-Viper, Russell's Viper
Manufacturer:
Pharmaceutical Industries Corporation
Phone:
+95-1-566742
+95-1-566750
Address:
192 Kaba Aye Pagoda Road,
Bahan,
Yangon,
Country:
Myanmar ( Burma )
Source: Clinical
Toxinology Resources
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