Tips to Limit Exposure to Browntail Moth Hairs While Outside

As caterpillars become more active, take precautions to protect your health

AUGUSTA – The Maine Center for Disease Control and Prevention (Maine CDC) and Maine Forest Service (MFS) remind Maine residents and visitors to take precautions to reduce exposure to browntail moth caterpillars, as they become more active this spring.

Browntail moth caterpillars shed tiny toxic hairs that can cause a skin rash similar to poison ivy or, if inhaled, trouble breathing. The Maine Department of Agriculture, Conservation and Forestry’s (DACF) MFS has found evidence of browntail moths in all 16 Maine counties.

As the weather turns warmer and people head outside, they should take precautions against increased risk from toxic browntail moth hairs. The greatest risk for exposure to the hairs is between April and July, when caterpillars are most active. Browntail moth hairs can land anywhere, including on trees, gardens, lawns, outdoor furniture, and decks. They may also be in the air. The hairs remain toxic in the environment for up to three years. Activities such as mowing, raking, and sweeping can stir up the hairs.

Most people affected by browntail moth hairs develop a rash that lasts for a few hours up to several days. In more sensitive individuals, the rash can be severe and last for weeks. Inhaling browntail moth hairs may cause breathing trouble that’s severe in some people and may require emergency medical attention.

Treatment focuses on relieving symptoms and ending ongoing exposure. There is no specific treatment for the rash or breathing problems caused by browntail moth hairs.

Browntail moth caterpillars are hairy, dark brown caterpillars with two red-orange dots on the back. Older caterpillars have two white stripes running from head to tail.

From left to right: A hand holding a twig with a browntail moth winter web; Many young browntail moth caterpillars basking on a winter web; Browntail moth cocoon; Comparison of younger (left) and older (right) browntail moth caterpillars 

Take these steps to protect yourself from browntail moth hairs:

  • Avoid places infested by caterpillars. Check for winter webs in spring when they are easiest to see. Visit theInteractive Browntail Moth Dashboard to see where DACF’s MFS notes high activity.
  • When performing outdoor activities that may stir up caterpillar hairs:
    • Aim for damp days or spray vegetation with a hose. Moisture helps keep the hairs from becoming airborne.
    • Cover face with respirator and goggles.
    • Tightly secure clothing around the neck, wrists, and ankles.
  • Take cool showers and change clothes after outdoor activities in infested areas.
  • Dry laundry inside to avoid hairs embedding into clothing.

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