Health risk posed by the Browntail Moth Caterpillar

Browntail Caterpillar

Just a quick post for those that reside in Maine , regarding the health risk posed by the Browntail Moth caterpillar.

The browntail moth caterpillar has tiny poisonous hairs that cause dermatitis similar to poison ivy on sensitive individuals. People may develop dermatitis from direct contact with the caterpillar or indirectly from contact with airborne hairs. The hairs become airborne from either being dislodged from the living or dead caterpillar or they come from cast skins with the caterpillar molts. Most people affected by the hairs develop a localized rash that will last for a few hours up to several days but on some sensitive individuals the rash can be severe and last for several weeks. The rash results from both a chemical reaction to a toxin in the hairs and a physical irritation as the barbed hairs become embedded in the skin. Respiratory distress from inhaling the hairs can be serious.

Caterpillars are active from April to late June. Hairs remain toxic throughout the summer but get washed into the soil and are less of a problem over time.

Browntail Larvae

Maine summary: 

The Maine Forest Service is receiving increased reports of caterpillars and their webs. Maine has known populations of browntail moths in Bowdoinham, Bath, Topsham, West Bath, Woolwich (Sagadahoc County) Brunswick, Freeport and Harpswell (Cumberland County) this year. The infestation is expanding south into Yarmouth and Cumberland (Cumberland County) and east into Wiscasset, Edgecomb and Boothbay (Lincoln County) and beyond.

The Maine Forest Service has seen pockets of infestation, some of them heavy, in other locations from Turner (Androscoggin County) to Waterville (Kennebec County) to Bristol (Lincoln County) to Kittery (York County).

Browntail moth control may be occurring in certain areas, but the risk to the public remains high in affected areas.

Information for providers:

Be aware of the risk of browntail moth rashes, particularly in areas with known risk.

There is no specific treatment for dermatitis due to browntail moths; treatment is focused on relieving symptoms and eliminating ongoing exposure.

The toxin is extremely stable and can remain a hazard for a long time.

Recommendations to reduce exposure:

•  Avoid places heavily infested by caterpillars
•  Take a cool shower and change clothes after any activity that might involve contact with browntail moth hairs
•   Dry laundry inside during June and July to avoid having the hair become impregnated in clothing
•  Wear respirator, goggles, and coveralls tightly closed at neck, wrists and ankles when performing activities that stir up caterpillar hairs such as mowing, raking, weed whacking, and removing pupal webbing from eaves and boats.
•  Perform these tasks on damp days or wet down material with a hose to help keep the hairs from becoming airborne

 

Skin rash caused by the exposure to the brown-tail larva

For more information:

 Maine Forest Service Browntail moth webpage: Browntail Moth Page