Calloselasma rhodostoma ( Malayan Pit Viper )
Original photo copyright © Dr Anita Malhotra
Family: Viperidae
Subfamily: Crotalinae
Genus: Calloselasma
Species: rhodostoma
Common Names: Malayan Pit Viper
Local Names: Ulah Kapak Bodoh , Ularkapak Daun ,
Ular Tanah , Ular Biludak , Ular Gebuk , Ular Bandotan Bedor , Ngu Kapa , Ngu
Kaba , Ngu Maaw-sao , Oraj Lemah.
Region: Southeast Asia
Countries: Cambodia, Indonesia, Laos, Malaysia,
Myanmar, Thailand, Vietnam
Calloselasma rhodostoma ( Malayan Pit Viper ) Original photo copyright © Dr Julian White
Taxonomy and Biology
Adult Length: 0.50 m
General Shape: Small to medium in length, stout,
flattened, but thick bodied snake, with a very short and narrow tail distinct
from the body. Can grow to a maximum of about 1.10 metres. Head is large,
broad, flattened, triangular shaped with a bluntly pointed and slightly
upturned snout and very distinct from neck. Canthus rostralis is distinct. Head
dorsum shields are large. Eyes are medium in size with vertically elliptical
pupils. Dorsal scales are smooth with apical pits. Dorsal scale count 23 ( 19 -
25 ) - 21 ( 19 ) - 17 ( 15 to 19 ).
Habitat: Elevations up to about 2000 metres but most
common in lowland forest, hillside slopes and cultivated regions. Particularly
common in dry secondary growth habitats, in rubber plantations and near rice
paddy fields.
Habits: Terrestrial and mainly nocturnal, but also
active during the day on occasions. Often found crossing roads at night. Tends
to be most active at times of high humidity. Tends to remain motionless to
avoid detection. Not an aggressive snake but will strike readily if disturbed.
Prey: Feeds mainly on rodents, lizards and frogs
and occasionally birds. Young feed on insects and small lizards.
Calloselasma rhodostoma ( Malayan Pit Viper ) Original photo copyright © Dr Wolfgang Wuster
Venom
General: Venom Neurotoxins
|
Not present
|
General: Venom Myotoxins
|
Not present
|
General: Venom Procoagulants
|
Fibrinogenases
|
General: Venom Anticoagulants
|
Not present
|
General: Venom Haemorrhagins
|
Present but not defined
|
General: Venom Nephrotoxins
|
Not present
|
General: Venom Cardiotoxins
|
Not present
|
General: Venom Necrotoxins
|
Secondary necrotoxic activity only
|
General: Venom Other
|
Not present or not significant
|
Calloselasma rhodostoma ( Malayan Pit Viper ) Original photo copyright © Dr Wolfgang Wuster
Clinical Effects
General: Dangerousness
|
Severe envenoming possible, potentially lethal
|
General: Rate of Envenoming
|
60-80%
|
General: Untreated Lethality Rate
|
1-10%
|
General: Local Effects
|
Marked local effects; pain, severe swelling, bruising,
blistering
|
General: Local Necrosis
|
Common, 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
|
Unlikely to occur
|
General: Myotoxicity
|
Not likely to occur
|
General: Coagulopathy & Haemorrhages
|
Common, moderate to severe coagulopathy + haemorrhagins
causing extensive bleeding
|
General: Renal Damage
|
Uncommon to rare, usually secondary effect
|
General: Cardiotoxicity
|
Unlikely to occur
|
General: Other
|
Shock secondary to fluid shifts due to local tissue
injury is likely in severe cases
|
Calloselasma rhodostoma ( Malayan Pit Viper ) Original photo copyright © Franck Principaud
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.
Calloselasma rhodostoma ( Malayan Pit Viper ) Original photo copyright © Franck Principaud
Treatment
Treatment Summary: Malayan pit viper
bites can cause severe local & systemic effects, potentially lethal, so
require urgent assessment & treatment with IV fluids, good wound care,
avoid early surgical intervention, early IV antivenom therapy (only effective
treatment for severe coagulopathy/bleeding).
Key Diagnostic Features: Local pain, swelling,
blistering, necrosis + coagulopathy, bleeding, renal failure
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: SAsTRC06
Antivenom
Name: Malayan Pit 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: SAsPBF01
Antivenom
Name: Antivenin Polyvalent (Equine)
Manufacturer:
P.T. Bio Farma ( Persero )
Phone:
++62-22-203-3755
Address:
Jl. Pasteur 28
Bandung
40161
Country:
Indonesia
3.
Antivenom Code: SAsGPO01
Antivenom
Name: Malayan Pit Viper Antivenom
Manufacturer:
Thai Government Pharmaceutical Organisation
Phone:
++662-644-8851
Address:
75/1 Rama VI Road,
Ratchathewi
Bangkok
10400,
Country:
Thailand
4.
Antivenom Code: SAsVRU01
Antivenom
Name: Calloselasma rhodostoma - Malayan Pit Viper Antivenom
Manufacturer:
Venom Research Unit
Address:
University of Medicine and Pharmacy
Ho Chi
Minh City
217 An
Duong Vuong Q5
Country:
Vietnam
5.
Antivenom Code: SAsVRU02
Antivenom
Name: Calloselasma rhodostoma - Malayan Pit Viper Antivenom
Manufacturer:
Venom Research Unit
Address:
University of Medicine and Pharmacy
Ho Chi
Minh City
217 An
Duong Vuong Q5
Country:
Vietnam
Source: Clinical
Toxinology Resources
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