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A Brief Guide to Snake Envenomations in Malaysia and Antivenom Therapy

Prof Tan Nget Hong (PhD, University of Chicago)a, Dr Tan Choo Hock (MBBS, University of Malaya) b,

Leong Poh Kuan (BBMedSc, University Malaya)b

Venom and Toxin Research Group aDepartment of Molecular Medicine, Faculty of Medicine, University of Malaya; bDepartment of

Pharmacology, Faculty of Medicine, University of Malaya

1. Introduction

Venomous snakebite leading to envenomation syndrome is a classifiable “disease” indexed by the WHO International Classification of Disease (ICD-10), and appropriately categorized as a Neglected Tropical Disease (WHO, 2009) that constitues a serious public health problem in the tropics (Chippaux, 1998; Kasturiratne et al., 2008). The severity of the issue unfortunately has been neglected systemically (Gutiérrez et al., 2006; Alirol et al., 2010), partly due to under-reporting and inconsistent

epidemiological studies that includes Malaysia. Earlier reports (year 1958 to 1980) estimated as many as 55000 cases of snakebites admitted to the hospitals in Malaysia, with majority of the bite cases came from northern states of Peninsular Malaya where agricultural activities were common. While the mortality rate of snakebite in Malaysia is only 0.3 per 100000 population (this figure appears though to be underestimated), complications like crippling deformity caused by the necrotizing effect of some venoms, and psychological trauma, are among features of prolonged morbidity that add to the human suffering, and significantly jeopardize the victims’ quality of life.

A survey at General Hospital Kuala Lumpur (1999-2003) alone indicated that snakebite affected

not only rural places but also suburban areas neighboring cities like Kuala Lumpur. It reflected

the fact that rapid and intense urbanization increased the chances of snake encounter as more

humans were encroaching into their habitats. In view of the global experience and the

development trend in our country, precautions and clinical guidelines need to be addressed

despite the fact that a more systematic and updated epidemiological study is yet unavailable.

2. Venomous Snakes of Malaysia

In Malaysia and the coastal waters of the region, there are at least 18 different species of

venomous front-fanged land snakes and more than 22 different species of sea snakes. These

venomous snakes belong to the following 2 families (3 subfamilies):

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Table 1: Medically important venomous snakes in Malaysia

Family Subfamily Genus Common names Main habitat

Viperidae Crotalinae - Calloselasma

- Cryptelytrops

- Tropidolaemus

- Parias

- Malayan pit viper (ular

kapak bodoh)

- Asian lance-headed pit

viper(ular kapak)

- Land

- Tree

Elapidae Elapinae

Hydrophiinae

- Naja

- Bungarus

- Ophiophagus

- Calliophis/

Maticora

- Laticauda

- Enhydrina

- Kerilia

- Hydrophis

- Thalassophis

- Pelamis

- Kolpophis

- Aipysurus

- Cobra (ular senduk)

- Krait (ular katang)

- King cobra (ular tedung selar)

- Coral* snake (ular karang*)

- Sea snake (ular laut)

- Land

*the name

‘coral/karang’

does not indicate

its habitat

- Seas and coastal

region

Only a few of the Malaysian venomous snakes can be regarded as of medical importance.

Epidemiological studies showed that in Malaysia, bites were mainly due to four species of land

snakes: Calloselasma rhodostoma (Malayan pit viper), Naja (Asian common cobra, there are

two species: Naja sumatrana (equatorial spitting cobra) and Naja kaouthia (monocellate cobra),

Cryptelytrops purpureomaculatus (mangrove pit viper) and Tropidolaemus wagleri (Wagler’s pit

viper). Other venomous snakes indigenous to Malaysia that are potentially dangerous to human

include Bungarus candidus (Malayan krait), Bungarus fasciatus (banded krait), Bungarus

flaviceps (red-headed krait), Ophiophagus hannah (king cobra), Parias sumatranus (Sumatran

pit viper) and the sea snakes. The species Cryptelytrops purpureomaculatus, Parais sumatranus

and Tropidolaemus wagleri (Wagler’s pit viper) belong to the Trimeresurus complex (Asian

lance-headed pit vipers). There are more than 7 different species of Asian lance-headed pit

vipers in Malaysia. Refer to Figure 1 (a-f: Elapidae; g-j: Viperidae; typical features for quick

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identification were given in parentheses but remember variations do exist) for pictures of some

medically important snakes in Malaysia, or contact the authors.

Figure 1 a: Naja sumatrana (white bands on neck); b: Naja kauthia (oval mark on hood);

Bungarus flaviceps (red-headed, red-tailed, body and belly black); d: Bungarus candidus

(alternate dark bluish and yellowish white bands); e: Bungarus faciatus (alternate black and

yellow bands); f: Enhydrina eschistosa (dark grey back, whitish sides);

a b

c d

e f

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Figure 1. g: Calloselasma rhodostoma (large scale over the head, stout, light brownish body

with dark brown saddles); h: Cryptelyptrops purpureomaculatus (olive to dark purplish brown;

a white line may present along each side); i: Cryptelyptrops albolabris (green above, pale green

or white below the eyes including lips); j: Tropidolaemus wagleri (green body with dark-

bordered scales; multiple green-yellow crossbars on the back).

Table 2 shows statistics of snakebites in West Malaysia, 1965-1971, based on data from 28

hospitals. Some recent reports, however, suggested that cobra bites are more prevalent that

bites by other snakes (Tan et al., 1990; Jamaiah et al., 2004; 2006).

g h

i j

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Table 2: Snakebites in West Malaysia

Snake Species Total Cases Fatal Cases

Malayan pit viper (Calloselasma

rhodostoma)

1136 4

Sea snake 158 5

Asian common cobra (Naja) 112 3

Asian lance-headed viper (Trimeresurus) 25 0

King cobra (Ophiophagus hannah) 6 0

Krait (Bungarus) 1 0

Unidentified 3765 6

Non-venomous 184 0

Report from monthly statistics of 28 hospitals throughout Malaysia, 1965-1971.

3. Biochemical composition of Snake Venoms

Snake venom contains mainly proteins (70-90%) and small amounts of metals, amino acids,

peptides, nucleotides, carbohydrates, lipids and biogenic amines. The protein components

include enzymes and non-enzymatic proteins/polypeptides and are usually the main toxic

compounds.

The main toxic principles in the venoms of elapid snakes (cobra, krait and sea snakes) include

polypeptide neurotoxins, polypeptide cardiotoxins and phospholipases A that may exhibit

presynaptic neurotoxicity or myotoxicity.

The main toxic principles of crotalid (pit viper) snake venoms are thrombin-like enzymes,

hemorrhagic proteases and platelet-aggregation inducers.

4. Elapid (cobras, kraits and sea snakes) Envenoming

Elapid venoms generally produce neurotoxicity and cardiotoxicity.

The earliest symptom of systemic elapid envenoming is a feeling of drowsiness or intoxication,

which starts from 15 min to 5 hr after cobra bites. Neurotoxicity manifested as progressive

descending flaccid paralysis often begin with bilateral ptosis (difficulty in opening the eyes:

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eyelids may remain completely closed though the patient usually remains conscious until

respiratory failure is advanced where hypoxia compromises consciousness), ophthalmoplegia,

facial muscle paralysis (with difficulty in opening the mouth, moving the lips) and bulbar palsy

(with aphonia, dysphagia, difficulty in protruding the tongue beyond incisors) within 1 to 4 hrs.

“Broken-neck sign” is a telltale sign that should be elicited as part of routine clinical

examination, especially in pediatric, delirious or semi-conscious patients. Fixed, dilated pupils,

limb weakness, loss of tone and deep tendon reflexes are other important signs. However, once

the paralysis involves the diaphragm and intercostals muscles, respiratory failure sets in even as

fast as 30 minutes within the bite. Mechanical ventilation hence should be on standby in any

case suspected of venomous snakebite.

Cardiotoxicity is caused by polypeptide cardiotoxin that affects both excitable and nonexcitable

cells, causing irreversible depolarization of the cell membrane and consequently impairing the

structure and function of various cells, thus contributing to muscle paralysis postsynaptically;

and cardiac complications e.g. arrhythmias leading to circulatory failure and systolic arrest.

Electrocardiogram (ECG) monitoring and perhaps cardiac enzymes test are therefore valuable in

monitoring the victims’ clinical progress.

Cobra (Naja sp.) venoms cause extensive local necrosis of the bitten limb, while krait and sea

snake bites do not usually cause local envenoming and can be virtually painless – hence the

possibility of late discovery and delayed treatment. Although it may not be fatal, local tissue

destruction should receive early attention and surgical intervention if indicated, in order to

salvage the limb function as much as possible. In addition, the equatorial spitting cobra is also

potentially responsible for ‘cobra-spit ophthalmia’ (with corneal ulceration and scarring,

secondary endophthalmitis) from its venom spat onto victims’ eyes.

Sea snake venoms contain both polypeptide neurotoxin (homologous to elapid neurotoxin) and

myotoxin, which is usually a basic phospholipase A2. The venoms cause respiratory failure

(neurotoxic effect) and myonecrosis (myotoxic effect), leading to rhabdomyolysis,

myoglobinuria and acute kidney injury. Generalized muscle pain/tenderness and stiffness,

trimus; and dark-brown urine are suggestive clinical features. Urine output and renal function

in these patients deserve close monitoring in anticipation of renal failure.

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Figure 2 a: ptosis, an early sign of neurotoxic envenoming; b: broken-neck sign in a child

envenomed by cobra in Malaysia (copyright the late Dr HA Reid); c: tissue necrosis complicating

a cobra bite.

5. Pit Viper Envenoming

The venom of pit vipers invariably causes edema, pain, blistering, hemorrhage and necrosis at

the bite sites, sometimes extending to the whole limb. Tender regional lymphadenopathy is not

uncommon as the venom is absorbed and distributed. Coagulopathy is the hallmark of systemic

envenoming by pit vipers, leading to spontaneous systemic hemorrhage. In Malayan pit viper

bite, the clotting defect is primarily due to thrombocytopenia, aggravated by defibrinogenation

syndrome. The commonest and earliest evidence of spontaneous systemic hemorrhage is

gingival bleeding. Persistent bleeding from the bite wound, blood-stained tears, petechiae,

purpura, ecchymoses, hemoptysis, hematemesis, epistaxis, and bleeding from other body

orifices are suggestive of hemostatic disturbances. Severe complications e.g. intra- or

retroperitoneal and intracranial hemorrhage, cardiac ischemia and hypovolemic shock are all

fatal sequelae but may develop slowy, hence the rationale for the victims’ coagulation profiles

to be monitored closely from the beginning even if antivenom has been given and patients

appear generally well. Where possible, blood product transfusion should be on standby in all

cases.

a b c

b Figure 3. Left: Ecchymosis; Right:

edema (usually followed by extensive

tissue sloughing and necrosis).

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6. Death Times

Generally speaking, deaths are most rapid following elapid bites and most protracted following

pit viper bites:

Snake species Average Death

time (hr)

Death time (hr)

– Range

King cobra (Ophiophagus hannah) -- ‘few min’- 6

Cobra (Naja) 8.4 ¼- 60

Malayan pit viper (Calloselasma

rhodostoma)

64.6 5-240

Mangrove pit viper (Cryptelytrops

purpureomaculatus

-- 12

The estimation of death times does not imply the allowance for delaying medical treatment,

but rather highlight the urgency to initiate indicated treatment as soon as possible, and to

thoroughly monitor the clinical progress of the patients.

7. First-Aid Measure in Snake Envenoming

1. Do not panic! Keep calm, reassure the individual as complete recovery is the rule.

2. Lie the patient down to ensure minimum activity. Keep the bitten part at rest, immobilize

the bitten limb with a splint or a sling – musculature contraction may increase the

absorption and dissemination of venom through bloodstream and lymphatics.

3. Consider pressure immobilization with compression bandage (using a broad, elastic,

stretchable crepe bandage) bound as tightly as for a sprained ankle, without

compromising the distal pulses. Only recommended for non-locally necrotizing

neurotoxic snakebite (king cobra, kraits, coral snakes and maybe sea snakes), otherwise

might cause more severe local tissue destruction and increased intracompartmental

pressure.

4. Avoid any interference with the bite wound to prevent hastening venom absorption,

worsening local bleeding or introducing infection. Washing or wiping the wound is

controversial (in addition, traces of snake oral secretion on the wound may be of value

for diagnostics in future). Do not attempt to cut the wound and suck out the venom.

5. Arterial tourniquets (and any tight ligature applied around the bitten limb) are not

recommended as this can lead to limb ischemia and gangrene; and worse still, when

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released there may be a dramatic increase of the venom dissemination systemically via

hyperemic response.

6. All patients with snake bites must be as soon as possible brought to the hospital for

treatment with absolute minimum movement of the body especially the bitten limb.

Where vehicles are not available, the victim should be carried using a stretcher.

7. Do not attempt to catch or kill the biting snake. However, if the snake has been killed,

bring it to the hospital for identification – but never allow handling of the snake bare-

handed as even a severed head can bite with reflex!

8. Diagnosis and Early Assessment of Snakebite Envenomation:

Two major questions when a snakebite victim presents at a healthcare centre are: the identity

of the snake inflicting the bite (diagnosis), and the severity of envenoming (early assessment):

a. Diagnosis of the biting species:

This can be ascertained by

i) Identification of the snake if the patient brings the snake to the hospital.

ii) Immunodiagnosis: this is costly and can be performed only in a well-equipped

laboratory. Presently not available in Malaysian hospitals. The facilities are

available at the Venom and Toxin Research Group at Faculty of Medicine,

University of Malaya.

iii) Clinical observation and inquiring circumstances of bite:

Systemic pit viper envenoming (bites by Malayan pit viper (Calloselasma

rhodostoma) and the Asian lance-headed pit vipers (Trimeresurus complex) is

characterized by non-clotting blood and other hemorrhagic syndrome

accompanied by rapid local swelling after the bite.

Systemic elapid envenoming (due to cobras and kraits) is characterized by

neurotoxic effects including ptosis, bulbar palsy, respiratory paresis and

sometime cardiac effects.

Systemic sea snake envenoming is characterized by myotoxic effects such as

myalgia, paresis, myoglobinuria, hyperkalaemia.

Note: NOT all snakes are venomous – for confirmed non-venomous bite, manage as

puncture wound.

b. Early assessment of the severity of snakebite envenoming can generally be made by

observing the extent of local envenoming effects and initial laboratory investigations.

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In ‘dry bite’ cases, venom was not injected although bite was inflicted by a venomous

species. Local signs and laboratory investigations usually are unremarkable. As with a

puncture wound, inflammation and potential infection should be managed accordingly.

In mildly envenomed cases, there are minimal local signs, with swelling in the

immediate vicinity of the wound, no oozing blood from bite site, and no significant

systemic manifestations. Laboratory investigations reveal no abnormalities.

In severe cases, there is swelling, usually massive and rapidly extending, accompanied

by greater pain. Early tender lymphadenopathy indicates fast venom systemic spread.

Early systemic features include nausea, vomiting, diarrhea, drowsiness, ‘heavy’ eyelids,

bleeding from gum or venepuncture and bite site, myalgia, passing brown urine, oliguria

and abnormal laboratory results (e.g. prolonged clotting time, or 20 min whole blood

clotting). In these patients, close monitoring is warranted and antivenom is usually

indicated.

9. Management Principles in Snake Envenomation

9.1 General management of snakebite:

General management of snakebite envenoming includes first-aid and the following

measures:

Adequate reassurance;

Immobilization particularly the bitten limb.

Venous access – precaution needs to be exercised in patients with coagulopathy.

All bitten patients, even without local or systemic features, should be admitted to

hospital for observation of at least 24 hours.

9.2 Antivenom Therapy

Antivenom is the only specific treatment for snake envenomation that is of proven value.

Early (anaphylactic), pyrogenic and late (serum sickness) reactions can occur following

antivenom treatment. Incidence of early reactions following antivenom administration

ranges from 3 to 5%. About 40% of these reactions involve severe systemic anaphylaxis

(bronchospasm, hypotension or angioneurotic edema), though few fatal cases have been

reported. Most authorities have recommended that antivenom should be diluted in

isotonic fluid and given by slow intravenous infusion. Prophylactic regimen e.g. adrenaline,

antihistamines and corticosteroids has been practiced in many places empirically especially

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for high risk patients. In asthmatic patients, prophylactic use of an inhalational adrenergic β2

agonist e.g. salbutamol has the rationale to prevent bronchospasm. Certainly, resuscitation

facility should be made available prior to the use of antivenom.

Antivenoms Suppliers

9.2.1. Thailand antivenoms

The main antivenoms producer in Thailand is Queen Saovabha Memorial Institute (QSMI),

Bangkok, Thailand. (Tel: 02-2520162, email info@saovabha.com, 1871, Rama IV Road,

Bangkok 10330).

Due to the geographical proximity of Thailand and Malaysia, many venomous snakes in

Thailand are similar or closely related to the venomous snakes in Malaysia, and hence

antivenoms produced by QSMI could effectively neutralize venoms from many species of

Malaysia venomous snakes. By adopting an evidence-based approach, the efficacy of Thai

antivenoms in neutralizing local (Malaysian) snake venoms has been researched in the

laboratory (of University of Malaya) for their potential therapeutic use in Malaysia (see

below and Table 3 for types of antivenoms and their efficacies).

QSMI Monovalent antivenoms:

Monovalent Thai cobra antivenom: effective against the two species of cobra in

Malaysia (Naja sumatrana and Naja kaouthia), as well as king cobra (Ophiophagus

hannah);

Monovalent king cobra antivenom: effective against king cobra (Ophiophagus hannah),

efficacy against Malaysian cobra venoms has not been examined;

Monovalent banded krait antivenom: effective against Malaysian banded krait

(Bungarus fasciatus) but not other kraits;

Monovalent Malayan pit viper antivenom: effective against Malayan pit viper

(Calloselasma rhodostoma) but not against Asian lance-headed viper (Trimeresurus

complex)

Monovalent green pit viper antivenom: effective against Asian lance-headed viper

(Trimeresurus complex) in general but not against Malayan pit viper

Monovalent Russell’s viper antivenom: there is no Russell’s viper (Daboia russelli) in

Malaysia

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QSMI polyvalent antivenoms

Recently, QSMI produced two new polyvalent antivenoms: Neuro polyvalent antivenom for

treatment of elapid (cobra/krait) bites, and Hemato polyvalent antivenom for treatment of

viper/pit viper bites

Neuro Polyvalent Snake Antivenom

This polyvalent antivenom is raised against venoms of Thai cobra (Naja kaouthia) king

cobra (Ophiophagus hannah), banded krait (Bungarus fasciatus) and Malayan krait

(Bungarus candidus). Preclinical tests in our laboratory indicated that the polyvalent

antivenom could effectively neutralize all cobras and kraits of Malaysia origin, and is

more effective against cobra venoms compare to the monovalent Thai cobra antivenom

produced by the same institute. (see Table 3 below)

Table 3: Neutralizaiton capactigy of venoms from Malaysia venomous snakes by the

Neuro polyvalent snake antivenom

Venomous snake Neutralization capacity of Neuro polyvalent antivenom

Neutralization capacity of Monovalent Thai cobra antivenom

Equatorial spitting cobra (Naja sumatrana)

1.84 mg/mL 0.92 mg/mL

Monocellate cobra (Naja kaouthia)

0.55 mg/mL 0.55 mg/mL

King cobra (Ophiophagus hannah)

8.19 mg/mL 2.46 mg/mL

Banded krait (Bungarus fasciatus)

1.38 mg/mL Not effective

Malayan krait (Bungarus candidus)

0.73 mg/mL Not effective

Red headed krait (Bungarus flaviceps)

1.47 mg/mL Not effective

All the venoms tested are from snakes captured in Malaysia. Neutralization capacity

is defined as the amount of venom neutralized by 1 mL of reconstituted antivenom.

The antivenom was reconstituted according to manufacturer’s recommendation: 10

mL of sterile water was added to each vial of antivenom.

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Hemato Polyvalent Snake Antivenom:

This polyvalent antivenom is raised against venoms of Malayan pit viper (Calloselasma

rhodostoma), White-lipped pit viper (Cryptelytrops albolabris) and Russell’s viper

(Daboia russelli). Preclinical tests in our laboratory showed that the Hemato polyvalent

snake antivenom could effectively neutralize venoms of:

(a) Malayan pit viper (Calloselasma rhodostoma), neutralization capacity of 7.2 mg/mL.

This is more potent that the monovalent Malayan pit viper antivenom produced by

the same institute (neutralization capacity 3.2 mg/mL)

(b) Mangrove pit viper (Cryptelytrops purpureomaculatus), neutralization capacity of

4.2 mg/mL;

(c) White-lipped pit viper (Cryptelytrops albolabris), neutralization capacity of 3.64

mg/mL.

It is likely that the Hemato polyvalent antivenom can neutralize venoms of other species

of pit vipers belonging to the Trimeresurus complex (Asian lance-headed vipers), as our

early work demonstrated extensive cross-neutralization of antivenom against species of

Trimeresurus complex (Tan et al 1994).

9.2.2 Australian CSL antivenom against sea snake

The Commonwealth Serum Laboratories from Parkville, Victoria, Australia produced

antivenom against sea snake. The sea snake antivenom is effective against sea snake

envenomation in Malaysia.

Antivenoms raised against cobra or krait venoms may be able to neutralize sea snake

venom, as they possess common (similar) venom toxins. The efficacy of cobra or krait

antivenoms against sea snake envenomation, however, has not been investigated.

9.2.3 Indonesia polyvalent antivenom serum

The Perum Bio Farma (Pasteur Institute) of Indonesia produced a polyvalent antivenom

serum. The antivenom (in liquid form) was raised against venoms from three venomous

snakes: Malayan pit viper (Calloselasma rhodostoma), Banded krait (Bungarus fasciatus)

and Javan spitting cobra (Naja sputatrix). The efficacy of this polyvalent antivenom against

envenomations by Malaysian venomous has not been investigated. However, it is possible

that this antivenom could neutralize venoms of Malayan pit viper, cobra and Banded krait

from Malaysia. However, the antivenom is likely to be ineffective against venom of Malayan

krait (Bungarus candidus) and Asian lance-headed viper (Trimeresurus complex). The

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contact address of Perum Bio Farma is Jl Pasteur 28, PO Box 1136, Bandung 40161. (Tel

+6222-83755).

9.2.4 India Polyvalent Antivenoms

There are several antivenoms manufactuers in India, most of them produced polyvalent

antivenom raised agains the ‘Big Four’ of India venomous snakes: Indian cobra (Naja naja),

Indian krait (Bungarus caeruleus), Russell’s viper (Daboia russelli) and saw-scaled viper

(Echis carinatus). Followings are results of the preclinical assessment of the efficacy of

Indian polyvalent antivenom (against Malaysian snake venoms) produced by two different

manufacturers: Vins Bioproducts Ltd (Hyderabad, India) and Bharat Serums and Vaccines

Limited (Mumbai, India). The polyvalent antivenom produced by Vins is termed ‘Snake

Venom Antiserum I.P.’ whereas the antivenom produced by Bharat is termed Anti Snake

Venom Serum, or ASVS.

Vins Snake Venom Antiserum I.P.

Vins’ polyvalent antivenom is weakly to moderately effective against venoms of Malaysia

cobras (neutralization capacity 0.22 mg/mL and 1.18 mg/mL, respectively, against Naja

kaouthia and Naja sumatrana venom), weakly effective against king cobra (O. hannah, 0.22

mg/mL) and Malayan krait (B. candidus 0.22 mg/mL). It is not effective against another

common krait in Malaysia: Banded krait (B. fasciatus). It is not effective against Malayan pit

viper (Calloselasma rhodostoma) and Asian lance-headed viper (Trimeresurus complex)

Bharat ASVS

The Bharat’s ASVS is only weakly effective against venom of the Equatorial spitting cobra (N.

sumatrana, neutralization potency 0.31 mg/mL) and Malayan krait (B. candidus,

neutralization potency 0.14 mg/mL). It is not effective against other Malaysian elapid

venoms or pit viper venoms.

Note: the fact that both Vins and Bharat polyvalent antivenoms were not effective against

Malaysian pit viper venoms is not surprising as the Indian polyvalent antivenoms were

raised against venoms from Russell’s viper and saw-scaled viper, both from the subfamily

Viperidae (true viper or Old World viper), whereas the Malaysian pit vipers (Malayan pit

viper and Asia lance-headed vipers) belong to a different (evolutionary distant) subfamily,

Crotalinae (pit viper). The toxinology of venoms from Viperidae snakes is significantly

different from that of venoms from Crotalinae snakes.

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RECOMMENDATIONS RE USAGE OF ANTIVENOMS IN TREATMENT OF SNAKE BITES IN

MALAYSIA

In Malaysia, particularly in the rural areas, species diagnosis is usually not possible. Hence

there is a need to have a polyvalent antivenom that can be used to for treatment of all

snake bites with systemic envenoming. Unfortunately, to date there is no such ‘cure all’

antivenom available.

The Indian polyvalent antivenom will not be effective against Malaysian pit viper bites. It

may be moderately effective in neutralization of cobra venom but unlikely to be of use in

krait bites.

The efficacy of Indonesia polyvalent antivenom against Malaysian snake venoms has not

been investigated, however, it is highly unlikely to be effective against venoms of the

Malayan krait, red-headed krait and pit viper of the Trimeresurus complex (eg, the

Cryptelytrops).

At the moment, the two Thai QSMI polyvalent antivenoms appear to be the most suitable

for treatment of systemic envenomations in Malaysia. It is easy to distinguish between

elapid (krait and cobra) bites and pit viper bites clinically—the former is mainly neurotoxic,

whereas the latter hemorrhagic. Neuro polyvalent antivenom can neutralize venoms from

all Malaysian cobras and kraits, whereas Hemato polyvalent antivenom can neutralize

venoms from all Malaysian pit vipers; except the Wagler’s pit viper, Tropidolaemus wagleri .

At the moment, there is no antivenom available to neutralize the venom of Wagler’s pit

viper.

9.3 Supportive/ Ancillary Treatment

a. If there is danger of respiratory paralysis, intubate or ventilate via tracheostomy.

Mechanical ventilation is recommended for patients with respiratory paralysis.

b. Treatment of local lesion: Massive tissue sloughing and necrosis, intracompartmental

syndrome, suppurative complications etc may need surgical intervention, however the

risks of surgery in a patient with hemostatic disturbances must be balanced against the

life-threatening complications of local envenoming.

c. Treatment of shock; correction of fluid imbalance (venous access is vital but topmost

care is needed for patients with hemostatic disturbances).

d. Renal replacement therapy (peritoneal dialysis in acute setting) if indicated.

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e. Anticholinesterases e.g. edrophonium can partly overcome blockade by postsynaptic

neurotoxins.

f. Tetanus prophylaxis: A booster of tetanus toxoid is recommended for all snakebite

patients in the absence of coagulopathy.

g. Antibiotic use if indicated for infected wound.

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Literatures on Malaysian venomous snakes and clinical observations and treatment of

snakebites in Malaysia:

Alirol, E., Sharma, S.K., Bawaskar, H.S., Kuch, U., Chappuis, F., 2010. Snake bite in South Asia: a

review. PLoS Negl Trop Dis. 4, e603.

Chippaux, JP and Goyffon, M., 1998. Venoms, antivenoms and immunotherapy.

Toxicon. 36, 823-846.

Gutiérrez, J.M., Theakston, R.D.G., Warrell, D.A., 2006. Confronting the Neglected Problem of

Snake Bite Envenoming: The Need for a Global Partnership. PLoS Med. 3, e150.

Harrison, R.A., Hargraves, A., Wagstaff, S.C., Faragher, B., Lalloo, D.G. 2009., Snake envenoming:

a disease of poverty. PLoS Negl Trop Dis. 3, e569.

Jamaiah, I., Rohela, M., Roshalina, R. and Undan, R.C. (2004) Prevalence of snake bites in Kangar

District Hospital, Perlis, West Malaysia: A retrospective study (Jan 1999-Dec 2000).

Southeast Asian J Trop Med Public Health, 35: 962-965.

Jamaiah, I., Rohela, M., Ng, T.K., Ch’ng, K.B.H., Teh, Y.S., Nurulhuda, A.L. and Suhaili, N. (2006)

Retrospective prevalence of snaket bites from hospital Kuala Lumpur (HKL), Southeast

Asian J. Trop. Med. Public Health, 37:200-206.

Kasturiratne, A., Wickremasinghe, A.R., de Silva, N., Gunawardena, N.K., Pathmeswaran, A.,

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