"At Your Service" Newspaper Column

 

Michael R. Milam

Agronomy Specialist and County Program Director

For Daily Dunklin Democrat-At Your Service

October 19, 2008

 

Pyemotes Itch Mites

 

            Last week, I received a phone call from Kim Hughes at the Dunklin County Health Department regarding the situation in the Malden School System. She gave me some back ground and indicated that the students had rashes and welts. She indicated that although scabies had been suspected, that the skin scrapings had been negative. This had been going on for some time and they did not have answers to tell parents.

            She indicated that a medical examiner had looked at the photographs of the rashes and said that they might be bites. I told Kim that I would contact our entomologist and get suggestions. I called Dr. Richard Houseman, University of Missouri, whose specialty is urban entomology. This is the study of insects in association with humans and their companion animals. This would include structural pests including spiders and mites.

            Dr. Houseman got right to the point. He indicated the symptoms that I described were similar to those caused by the Pyemotes itch mite (Pyemotes herfsi) pronounced "pie uh moat eez". He told me that there had been several outbreaks in Nebraska, Kansas, Missouri, and other states. I. He referred me to some on-line resources and he sent me a PowerPoint presentation on biting arthropods. This presentation was related to Pyemotes itch mite, bed bugs, and mosquito transmission of West Nile virus.

            I am very familiar with mites. They have eight legs and are not insects and generally much smaller.  Most mites don’t cause problems but there are some species that do. They are literally everywhere. We have spider mites in watermelon, cotton, and ornamental plants. I have recognized the pattern of crop injury that spider mites cause merely by driving by the fields. I have also seen mites in schools and in people’s homes. Last year, I found red mites at an elementary school that do not feed on humans. We also have dust mites in our homes that can be an asthma trigger. But this was the first time that I had learned of the itch mites.

            According to the on-line literature, The U.S. Centers for Disease Control estimated that during an outbreak in 2004 that 54 percent of the residents of Crawford County, Kansas or 19,000 people had suffered from their bites. The mites were feeding on the midge larvae that caused the oak leaf gall. While this mite is also called the oak leaf gall mite, this is misleading since the Pyemotes itch mite has been documented feeding on other species of insects. According to a report from the Illinois Department of Public Health, the outbreak in Chicago in 2007, the mites were documented for the first time to feed on the eggs of the periodical cicada. In fact, insects from at least 5 insect orders and 9 families occupying a range of habitats have been recorded as hosts for the Pyemotes itch mite. In 2008, the itch mites have been reported as problems in Hamilton and Ross Counties in Ohio by their respective health departments.  

            These mites inject neurotoxin-containing saliva into the humans which starts with a rash that is red and itchy and then develops into lesions that look like pimples. The treatment for the rashes is the same for any dermatitis. Apply calamine lotion, oral antihistamines, and topical corticosteroid creams.

 I talked with Amy Coleman, the nurse at the Malden Elementary School, and with Bob Wilson, assistant superintendent of the Malden Schools. I sent him information regarding the Pyemotes itch mite. I also contacted Autumn Grim, who is with the Missouri Department of Health and Senior Services, Division of Community and Public Health. 

We were sharing information and trying to put the pieces of the puzzle together. When I heard back from the individuals who had seen the information and learned that the pictures of the mite bites looked like what they had observed, I felt confident that we were on the right track. 

            Since it was raining outside, I knew that it would not be a good time for any outdoor sampling. However, once the weather cleared I visited campus and the surrounding area. I was looking for insects that bite such as tumbling flower beetles, minute pirate bugs, and lace bugs. I could not find any of these insects in my sweep net. I could not find any oak leaf galls on campus nor surrounding yards. However, I did find several mites associated with the fuzzy bead gall and I found a few mites in an oak stem gall. These are not the traditional hosts of the Pyemotes mite. There were very few mites found but it appeared to be several different types. I invited Kim Hughes to come by my office and see them under the microscope. After we viewed the mites, I called Bob Wilson and reported that we had found mites. At this time, it is unsure if these mites are related to the outbreak. However, the presentation of the skin rashes is consistent with those caused by Pyemotes itch mite.  

I made a separate trip to Malden earlier this week and found more galls and more mites. However, we still don’t have good information where the children and adults came into contact with the mites or why the situation occurred in Malden and not surrounding communities.

We do have several options that we can do to follow-up on leads that we develop. However, we are late in the cycle of the outbreak; we may never know what really happened.

With the interest that has been generated because of the suspected mites, my co-worker, Sarah Denkler, and I are working on links to our Dunklin County Extension website. We hope to have the links in place by the time the article runs in Sunday’s paper. Our website is located at http://extension.missouri.edu/dunklin/. We will have an icon that can be clicked to get to the various articles.

Anyone with questions can call me at (573) 888-4722.

University of Missouri Extension programs are open to all

 

 

 

Return to 'At Your Service' Archives