Most people associate bees, wasps, and ants with venomous insect stings, but the danger posed by venomous caterpillars is often overlooked by the public. The term “caterpillar” refers to the wormlike immature form of both moths and butterflies. Butterflies are one of the few groups of insects that people often enjoy finding in the wild, and they are ecologically beneficial due to their pollinating activity. Moths, on the other hand, are sometimes considered pests due to their habit of flying around indoor and outdoor lights in large numbers, but they are not considered a threat to public health, and many species also pollinate plants. This is not the case for caterpillars due to the venomous protruding “spines” that coat the bodies of many species. Coming into contact with these spines has sent thousands of people to the hospital in just the past two years. There’s a staggering 165,000 total caterpillar species worldwide, but only 12 families are known for causing human injury. Unfortunately, many of these species maintain a native or invasive presence within the northeast United States.

During 2009, poison control centers across the US reported nearly 1,500 medically significant caterpillar evenomations across the country. Many of these cases, and others that were not reported to poison control centers, required medical treatment. Most caterpillar envenomation victims are below the age of 18. This is because dangerous caterpillars are often willingly handled by young children while they play outdoors. However, epidemic cases of caterpillar envenomations have occured in all northeastern states. For example, during 2017, an invasion of browntail moth caterpillars in residential areas of Maine caused hundreds or possibly thousands of rashes and breathing problems in residents of the state. Experts claim that just being in an area where browtail moths are abundant is enough to cause mass envenomations, as the caterpillar’s venomous hairs become airborne before attaching to human skin. So avoiding physical contact with a brown tail moth specimen is not enough to prevent envenomation symptoms in areas where they are prevalent. Other New England areas, including Cape Cod, have also seen medical epidemics of browntail moth caterpillar stings, and this is not the only species that can cause epidemics of this sort. Other caterpillar species to look out for in the northeast include Gypsy moth caterpillars, tussock moth caterpillars and hag moth caterpillars.

Have you ever experienced a skin rash that you believe may have been caused by airborne caterpillar spines?