Lateralising Neurological Signs of Intracranial Bleeding
Necrosis from a West African carpet viper, Echis ocellatus bite
Bite from a spitting cobra
| Despite the recognition of snakebite as a significant neglected public health issue by the World Health Organization, and other agencies, progress to resolve the problem has been limited in tropical ecozone regions of the world where it is needed most. Additional efforts by toxinology leaders/scientists, and the recently established Global Snakebite Initiative are in current pursuit of resolution, but are constrained by limited economic resources. In addition, the lack of recognition of the magnitude of this problem by regional and national health authorities in many parts of the world further complicates the solution of this problem.
The true impact of snakebite may never be known, especially in respect to the fact that most snakebites occur in rural, underserved areas with poor case reporting. The primary burden of snakebite envenomation falls on the inhabitants of developing countries in tropical and subtropical regions. Indeed, the highest morbidity and mortality rates occur in South Asia, Southeast Asia, and sub-Saharan Africa.
Snakebite has also been overlooked as an occupational hazard with most bites occurring on the feet, legs and hands of agricultural workers. Venomous snakebite patients all too frequently receive inadequate treatment due to a lack of antivenom availability, and in many instances due to the unavailability of antivenom with good pharmacotherapeutic effectiveness. The native people of Sri Lanka suffer 40,000 venomous snakebites annually, and the country has one of the highest snakebite mortality rates in the world. The difficulty of treating snake envenomed patients with less than optimal therapy is frustrating for medical professionals, and of considerable health costs and personal loss to the patient.
The bite from a venomous snake resulting in envenomation can have serious consequences causing disability and death. The snake species causing the highest morbidity and mortality rates world wide are those from the families Viperidae (true vipers, lance-head pit vipers, and rattlesnakes) and Elapidae (kraits, cobras, coral snakes, mambas, Australasian snakes and sea snakes). The species responsible for the most problems differs depending on the region.
Envenomings cause a variety of effects on the body, both local (at the site of the bite and adjacent tissue) and systemic (via circulatory system, involving distant, multiple organs of the body). The most critical consequences of snake bite envenoming include shock, spontaneous systemic bleeding, paralysis involving respiratory muscles, generalized break down of skeletal muscle (rhabdomyolysis), acute renal failure and infection of necrotic tissue at the site of the bite. The chemical composition of venom is complex, varying among different species and even within individuals of the same species. The damaging effects of envenomation occur rapidly after a bite making the time between sustaining the bite and receiving treatment of paramount importance.