INTRODUCTION AND EPIDEMIOLOGY
The phylum Arthropoda is the largest division of the animal kingdom. The phylum includes insects (bees, wasps, hornets, flies, mosquitoes, bedbugs, fire ants, caterpillars, fleas), arachnids (spiders, scorpions, chiggers, ticks), and crustaceans (shrimp, lobsters, crabs). Venomous bites and stings from arthropods are a significant worldwide problem.1 In the United States, the American Association of Poison Control Centers reported almost 50,000 cases of exposures to arthropods in 2012.2 Some of these were listed as resulting in major or severe reactions, including severe pain, neurotoxicity, or other signs and symptoms. Fatalities among these exposures are rarely reported to poison centers and usually result from allergic reactions to Hymenoptera stings. Toxic reactions to multiple stings by members of the order Hymenoptera and severe systemic allergic reactions to one or more stings or bites of other insects, such as deerflies, blackflies, horseflies, and kissing bugs, can all present as emergency, life-threatening situations.3 Other arthropod bites and envenomations merit review either because they cause specific organ system toxicity or because they can result in transmission of infectious disease. This chapter discusses the most common and serious arthropod bites and envenomations. Tick bites are discussed in the "Tickborne Zoonotic Infections" section of chapter 160, "Zoonotic Infections: Tickborne Zoonotic Infections."
HYMENOPTERA (WASPS, BEES, AND ANTS)
More fatalities result from stings by these insects than by stings or bites by any other arthropod. There are three major subgroups or superfamilies of medical importance: (1) Apidae, which includes the honeybee and bumblebee; (2) Vespidae, which includes yellow jackets, hornets, and wasps; and (3) Formicidae, or ants.
BEES AND WASPS (APIDAE AND VESPIDAE)
Apids, such as honeybees and bumblebees, are usually docile, stinging only when provoked. A female honeybee is capable of stinging only once (male bees have no stinger), because its stinger has multiple barbs that cause the sting apparatus to detach from the bee's body, which leads to evisceration and eventual death.
Africanized honeybees, or so-called killer bees, are now found in most of the southern and warmer regions of the United States extending from coast to coast. These bees are hybrids of African bees that escaped from laboratories in Brazil during the 1950s and have successfully spread northward along the coasts and temperate regions of the continent. Their venom is no more toxic than that of their American counterpart, but Africanized hybrid honeybees are more aggressive, and a hive can respond to a perceived threat with >10 times the number of bees that respond from a hive of typical North American bees. An attack from Africanized bees can lead to massive stinging, resulting in multisystem damage and death from severe venom toxicity.4,5
Most of the allergic reactions reported each year due to Hymenoptera occur from vespid (wasp, hornet, and yellow jacket) stings. These arthropods nest in the ...