It is well known to residents of the northeast that numerous caterpillar species are outfitted with venomous spines that can trigger allergic reactions in humans. Obviously, handling a venomous caterpillar species will cause unpleasant physical symptoms for any human, even those who have never suffered from allergies. However, a caterpillar’s venomous spines often become airborne after being shed. These detached spines float through the outdoor environment where they can make contact with human skin, leading to skin irritation and rashes. For example, rash outbreaks have occurred in residential areas of Massachusetts during seasons that saw an abundance of Gypsy moth caterpillars within neighborhood trees. An abundance of browntail moth caterpillars in residential areas of Maine has led to an outbreak of rashes among residents, and this outbreak is occuring now. However, more and more people have recently been reporting skin rashes, breathing difficulties and other allergic reactions in areas where caterpillars have already matured into adult moths. As it turns out, these outbreaks are being caused by both discarded and occupied cocoons of tussock moth caterpillars.

After maturing into moths, caterpillars that inhabit residential and urban trees discard their cocoons. These cocoons then become abundant in residential lawns and parks, and unfortunately, these cocoons still contain the caterpillar’s venomous spines. These spines become dislodged from cocoons by wind currents which can bring the spines in contact with human skin, and this is what has been happening in regions where the douglas fir tussock moth was abundant. Cocoons that are still occupied by developing caterpillars are also causing allergy symptoms. It is hard to determine the percentage of the population that is allergic to tussock moth spines, but the Centers for Disease Control and Prevention estimate that between 12 and 22 percent of children may be allergic. In areas where people are experiencing seemingly inexplicable allergy symptoms, the cause may be due to these cocoons. Residents can remove these cocoons from their property, but only after wearing protective clothing, like long pants, long-sleeved shirts, closed-toe shoes, gloves and a hat. The cocoons should be placed into a plastic bag before being thrown into an outside garbage receptacle. The most common tussock moth caterpillar species in the northeast include the white-marked tussock caterpillar, the banded tussock caterpillar, the milkweed tussock caterpillar, the sycamore tussock caterpillar and the yellow-based tussock caterpillar.

Do you believe that you have ever fallen victim to caterpillar-induced allergic reactions?