Monday, December 3, 2012

Entomology in Knoxville: Human health

3000 entomologists swarmed to the 2012 ESA annual conference
in scenic Knoxville, TN.  Over 1800 papers and 600 posters reported
on all aspects of  the science, including urban entomology.
Every year I try to attend the Entomological Society of America's annual conference. It's one of the largest gatherings of entomologists you'll find anywhere in the world, and there's always a lot to learn.  I also try each year to give you my readers a little taste of what the meetings are like, and what's new in the structural pest control field. In this post I wanted to cover some of the human health-related papers.

Delusions of Parasitosis 

One of the many meeting symposia at ESA was dedicated to the subject of delusions of parasitosis, a condition where people delude themselves into believing that non-existent insects are on them, or in their bodies, or infesting their home. This is a relatively common problem across the country. Cynthia Lord and Roxanne Connelly with the University of Florida reported handling 338 probable cases of delusions of parasitosis (where no insects were ever found) over 13 years of Extension work--approximately two per month (this frequency of contact is very similar to what I  encounter at my office in Dallas, TX). Dr. Nancy Hinkle at the University of Georgia sees even more cases, up to 3-4 people per week, to the point where she has hired a patient psychiatrist to assist her with handling such visitors. All speakers at the symposium agreed that such calls are extremely time-consuming, and rarely result in a satisfactory outcome without the intervention of family or skilled medical professionals.

Recent authors have criticized a published article claiming
to have seen springtails in human skin scrapings. 
Earnest Barnard, entomologist with the University of Tennesse, debunked the idea (prevalent on the Internet) that Collembola (springtails) might be responsible for some mystery bug cases.  Dr. Barnard, who is an expert on the Collembola, noted that springtail mouthparts are retracted into the head and are incapable of burrowing into skin as some have suggested. He addressed a scientific paper purporting to have found Collembola in skin scrapings from patients diagnosed with delusions of parasitosis. His study of the paper showed that the authors manipulated electron micrographs to create images that look like a Collembola. He noted that the purported parasites were far too small to be real Collembola, based on the paper's own size measurements. A website at the University of California - Davis does a good job of showing all known human skin parasites and critically evaluating the misinformation so common on the Internet.

Lynn Kimsey, with the University of California - Davis, noted the lack of cross-communication among disciplines concerning delusions of parasitosis. She looked at some of the underlying causes of unexplained itching and broke them into four categories: peripheral (e.g, resulting from solar elastosis and other skin disorders, autoimmune disease, bites, contact dermatitis), neurogenic (e.g., the result of drug side effects), psychogenic (e.g., hallucinations, delusions, OCD), or pathogenic (symptoms resulting from an organic disease, such as diabetes). She suggested that entomologists should advise clients to avoid telling their doctor that they believe they have skin parasites when describing their symptoms. In this way the doctor is less likely to dismiss the complaint as psychological and more likely to consider a wider spectrum of possible causes for creeping, itching and biting sensations on the skin. She suggested referring mystery bug clientele to internal medicine specialists, especially those with an emphasis on neuromedicine, as these doctors tend to take a more wholistic view of the patient than the average dermatologist or GP. All speakers agreed that entomologists should avoid referring to "bites" when discussing mysterious skin lesions with a client, avoiding reinforcement of what is frequently a false perception.

Urban Highlights of 2012

Sometimes these meetings are a good opportunity to catch up on "older" research--research that may have been conducted a year or two earlier, but is just now getting published. Roberto Pereira, of the University of Florida, devoted a session to reviewing the highlights of urban entomology in 2012. According to two studies published this year from North Carolina State University, bed bug populations around the U.S. are very diverse genetically, but often very similar genetically within communities and especially within apartment complexes. These data suggest that bed bugs have been introduced many times into the U.S. from different foreign sources. They concluded that nearly all the studied infestations in isolated apartment complexes were started by a small starter infestation, possibly consisting of a singly mated female and/or her progeny. What's cool about these studies is how the ability to peer into the DNA of bed bugs is giving us new insight into how these insects spread--something we could only speculate about a few years ago. One of the two studies authors, Ed Vargo, elaborated on these findings later in the meeting. After looking at 61 populations in 21 states they believe there is a strong international connection between bed bug populations in the U.S. and Canada and Europe.

In other bed bug literature, a couple of papers explored the mental health impact of bed bugs.  Goddard and deShazo report in the American Journal of Medicine that many people experience symptoms similar to Post Traumatic Stress Disorder (PTSD) following bouts with bed bugs.  Susser and colleagues from Canada reported in the online journal BMJ Open a variety of anxiety, sleep disturbance and even depression associated with bed bug infestations.

Finally, at least one lawyer this year suggested that OSHA should be more interested in bed bugs. He argued in the Toxics Law Reporter that the ability of bed bugs to harbor certain blood borne parasites puts workers in the pest control, hospitality and housing industries at increased risk of infection. This idea should be of interest all of us who have ever smashed bed bugs with ungloved (or gloved) hands. What this would likely mean to our industry, should OSHA get involved, would be increased training requirements for employees and need to provide technicians with additional safety gear--some of which is probably not a bad idea.

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