Venomous Animal Injuries

Venomous animals account for considerable morbidity and mortality worldwide. Snakes alone are estimated to inflict 2.5 million venomous bites annually, with approximately 125,000 deaths. The actual numbers may be much larger. Southeast Asia, India, Brazil, and areas of Africa lead the world in snakebite mortality. It is impossible to estimate the worldwide morbidity and mortality resulting from other venomous animals such as bees, wasps, ants, and spiders. Approximately 45,000 snakebites occur annually in the United States; 7000 to 8000 are inflicted by venomous snakes, and 5 to 10 result in death. Insects are responsible for 52% of deaths, snakes for 30%, and spiders for 13%. Specifically, bees are responsible for the most fatalities, followed by rattlesnakes, wasps, and spiders. Historically, most of the recorded deaths from spider bites were caused by the black widow, although the brown recluse spider has been implicated in an increasing number of deaths. The American Association of Poison Control Centers began collecting data in 1983 on deaths caused by venomous animals. Their 25-year experience shows a significant number of exposures by bite or sting but relatively few deaths (Table 62-1). Although these data include most of the United States, there is no requirement that hospitals, emergency departments, coroners, or public health agencies report deaths or exposures to regional drug and poison information centers. This decline in deaths may be caused by an actual decrease in mortality or may be a result of inadequate reporting. Meaningful morbidity data, such as the number of amputations, hospitalizations, and disabilities, do not exist. The number of exposures and deaths from exotic snakes seems to be increasing, possibly because of interest in collecting so-called “hot” or venomous varieties such as cobras, mambas, and vipers. The morbidity from marine animal injuries is increasing in proportion to the number of people exposed to the ocean and the number of private collectors, but the mortality has not increased dramatically. An increase in outdoor recreational activities, such as camping, scuba diving, and wilderness trekking, puts more people in proximity to venomous animals and increases the risk of envenomation. Most exposures occur from April to October, when animals are most active and potential victims are outdoors and involved in activities that might increase their risk for envenomation. Of course, many spider bites and exotic animal envenomations that occur indoors can take place at any time. Most deaths seem to occur in very young, elderly, or inappropriately treated patients. Venom Delivery