Snakebite: Epidemiology

SNAKEBITE

Epidemiology

Snakebites are reported from virtually every part of the world, except those countries where snakes (especially venomous snakes) are relatively rare. The incidence of serious bites is significantly higher in the tropics than in indus-trialised nations of the West. This is exemplified by the fact that while the USA records 6,000 to 8,000 venomous bites per year, with mortality ranging from 5 to 15 deaths, India records about 200,000 bites, of which nearly 15,000 end in death. In Britain, hardly 200 bites are reported each year, and only 14 deaths have occurred in the last 100 years!

Epidemics of snakebite have resulted from a sudden increase in snake population density, for example after flooding in Columbia, Pakistan, India, and Bangladesh. Invasion of the snake’s habitat by large numbers of people may also be followed by an increased incidence of snakebite. This occurred during the construction of new roads through jungles in South America, and during the movement of farmers to newly immi-grated areas in the former dry zone of Sri Lanka. Among the various states in India, Maharashtra records a high incidence of snakebites—more than 1,000 bites per year. Most of the bites are reported from rural parts of the state. Other states with significant reportage of snakebites include West Bengal, Uttar Pradesh, Tamil Nadu, and Kerala. Most of the bites are said to be due to saw-scaled viper (almost two-thirds), while one-fourth of the number is due to Russell’s viper; cobra, krait, pit viper, etc., account for only a small number of cases. A recent report from South India indicates that nearly 20% of poisoning cases admitted to hospitals could be due to envenomations.