Note to Editors: For a 300 dpi jpeg photo of a Pyemote ( itch mite) contact Donise Osbourn at dosbourn@oznet.ksu.edu  or 785-532-5806.

Released: October 22, 2004

Itch Mite Outbreak May Be First in North America

MANHATTAN, Kan. – The species of itch mite that made news in southeast Kansas and other parts of the Midwest last summer may have been in the region a few times before. Even so, the 2004 infestation apparently was its first confirmed appearance in the United States, according to Kansas State University Research and Extension entomologists Alberto Broce, Ludek Zurek and Robert Brown.

“We identified this particular mite as a Pyemotes – commonly known as an itch mite – through our collaborative work with personnel from the University of Nebraska’s Department of Entomology, the Crawford County Health Department, Kansas Department of Health and Environment, Pittsburg State University, and the U.S. Centers for Disease Control and Prevention,” said Broce. “We now are investigating K-State reports from 1992-94 of similar, but not as extensive, bite outbreaks, in order to estimate how long ago this mite might have entered North America.”

The mites made headlines when mysterious bites were reported in early September from the Pittsburg, Kan., area, Broce said. Soon after, bites were reported by residents of Manhattan, Kan.; Lincoln, Neb.; several other communities in eastern Nebraska; and Joplin and Saint Louis, Mo.

There is no pain when these mites bite, he said. In fact, most people are unaware that they have been bitten until the next day, when quarter-size reddened welts appear with a pimple on their center. The bites are most

commonly distributed over the neck and shoulders and on the upper torso where clothing hangs loosely. They appear after people have been involved in outdoor activities.

In a few cases, people with numerous bites this year visited physicians or even went to a hospital emergency room.

In some areas where the outbreaks occurred, genus Pyemotes dust mites were found feeding on midge larvae that cause the marginal leaf galls in pin and red oak trees, Broce said.

Pregnant (gravid) Pyemotes female mites with distended abdomens give birth to up to 250 adult mites that mate immediately after emerging from their mother.

These tiny mites – invisible to the naked eye – are dispersed by the wind; so, bites can occur on people situated downwind and away from infested trees, the entomologist said.

Cal Wellbourn, entomologist in the Division of Plant Industry at the Florida Department of Agriculture and Consumer Services in Gainesville, further identified the mite as Pyemotes herfsi. The species is from Central Europe, where it feeds on larvae of various moth species, Broce said.

“This is the first time the presence of this particular species of itch mite has been confirmed in North America,” he said.

Although the mites prefer to feed on moth larvae, there are numerous reports from Europe of this species’ biting humans.

Repellents based on DEET do provide protection from the bites. A change of clothing and a hot, soapy shower after working out of doors – especially around oak trees – should help reduce the incidence of the bites, Broce said. Spraying insecticides in the environment does not appear to help in fighting the mites.

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K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.

Story by:
Mary Lou Peter
mlpeter@oznet.ksu.edu
K-State Research& Extension News