The trillions of periodical cicadas that emerged across multiple US states this year may have vanished, but they've left behind itchy traces. Oak leaf itch mites, known for feeding on cicada egg nests, are now causing painful rashes in humans.
These mites are nearly invisible to the naked eye, measuring around 0.2 millimeters long. Originating in Europe, they were first detected in the US in Kansas in 2004 and have since spread to numerous states, including Illinois and Texas. Carried by the wind, these mites can travel long distances, furthering their reach.
Oak leaf itch mites typically feed on the larvae of a midge, a type of fly that creates galls on pin oak leaves. After feeding, the mites drop from the trees, often landing on humans or animals, resulting in itchy rashes and small, raised bumps.
While these mites usually feast on insects, they can inadvertently bite humans when searching for food, especially during late summer and fall when their populations peak. People are most likely to be bitten while gardening or raking leaves from infested pin oak trees.
To treat bites, experts recommend avoiding scratching to prevent secondary infections. Over-the-counter products can help relieve itching, and medical attention should be sought if symptoms worsen. Preventative measures include bathing after exposure and wearing protective clothing like long sleeves, gloves, and hats.
The connection between cicada emergences and mite bites was first documented in 2007 in Chicago, following the emergence of Brood XIII. This year, Brood XIII (17-year cycle) and Brood XIX (13-year cycle) emerged across 17 states, marking a rare double-brood event. The next simultaneous emergence of these broods isn't expected until 2245.
The abundance of cicadas during their brood years appears to boost mite populations, leading to more frequent mite bites in affected areas. While the cicadas are gone, the oak leaf itch mites continue to remind us of their presence.
