Management of Exotic snake bite in Australia

Fig 1 Naja kaouthia

MANAGEMENT OF EXOTIC SNAKE BITE IN AUSTRALIA

Associate Professor James Tibballs

Exotic snakes - either imported legally or illegally, or bred in captivity - represent a serious health problem. A number of significant problems exist with the management of bites by exotic snakes within Australia.

1. Lack of medical knowledge. The vast majority of Australia's venomous snakes are elapids, a few are colubrids. Many exotic species are cotalids or viperids. The envenomation syndromes caused by Australia's elapid snakes are well recognised by personnel charged with providing medical treatment. The same however, cannot be said for the management of exotic snake bites. Few medical personnel would be cognizant of the effects of exotic snake bites. Australian elapids cause mainly neurotoxic, coagulopathic, myolytic and to some extent haemolytic problems. Exotic snakes, may cause, in addition to these problems (determined by species), severe local tissue destruction which may threaten the viability of a limb as a matter of course. Although local tissue damage may occur with some Australian species, notably by members of the Black Snake genus, the damage is usually slight. Not so in the case of bites by many viperid and crotalid species. Limb loss, if not life loss, is a real possibility. Australian medical personnel simply do not have experience or expertise in the management of this problem.

2. Lack of suitable antivenoms. The backbone of medical treatment for snake envenomation is antivenom therapy. Australia simply does not routinely stock appropriate antivenoms for treatment of exotic snake bite. Since many antivenoms only neutralize the venom of a specific snake, a bite by an exotic species may be untreatable. It is foolhardy to assume that treatment is possible. Although some exotic snake antivenoms are maintained by some zoological institutions or by licensed private institutions, this does not mean that any case of exotic snake bite is easily treated. The stock maintained by institutions has limited applicability only to the species maintained by that institution. In addition, there are problems of access and payment. Exotic antivenoms are expensive and a scarce resource - unlikely to be afforded by and easily released to private collectors.

3. Bites are to be expected. Even competent snake handlers inevitably get bitten. In a study by Prof John Pearn and others (Med J Aust 1994; 161: 706-708), the average number of venomous bites sustained by experienced herpetologists in Australia was over 4, with a life-threatening bite every 10 years. The message is that no matter how careful or experienced a snake handler is, a bite will occur - sooner or later! All persons coming into contact with such snakes are at risk, not only herpetologists. Personnel at points of entry into Australia, or family sharing or others entering the abode of an exotic snake collector may be at some risk.

4. Failure of species recognition. Even the expert sometimes has difficulty trying to identify an Australian species. This problem is probably magnified many times with the identification of exotic species both by 'experts' and by non-experts alike. No help can be expected by untrained personnel. It is too simplistic to assume that all species of a genus have similar effects and require the same antivenom treatment. Within a genus, for example Cobras (Naja), many species exist - which require a specific antivenom. Differentiating such species may be difficult, and erroneous. In the case of a bite, this may lead to selection of a wrong (and ineffective) antivenom.

For all these reasons, the management of exotic snake bite in Australia is problematic. The survival of a victim bitten by an exotic venomous snake cannot be assured, let alone preservation of a bitten limb. The following are recommended:
a) The collection and maintenance of exotic snake species in Australia be confined to official institutions and licensed collectors.
b) Institutions be required to maintain adequate stocks of appropriate antivenoms.
c) Institutions be required to have prepared an action plan in association with a nearby medical facility to manage envenomation.