Bat mites and bat ticks...really?

Bat mite bites to humans are rare, most commonly occurring
when biologists handle infested bats or work in caves among
mite-infested colonies. Photo: Elaine Miller Bond

For me it's not uncommon to get questions about biting mites in homes. While some cases can be traced to actual infestations of rodent or bird mites, most do not. In cases where I cannot detect a valid pest, and the pest physical description or behavior doesn't reasonably match any known pest, I consider the case to likely be a non-pest problem.

However a recent email begged for help with some sort of biting bug in their home.  The bug could not be seen, the writer said, but two pest management companies suggested the problem could be either bird mites or "bat mites". According to the email, both companies treated the home with insecticide but (surprise!) the treatments did not solve the problem.

It being winter, and the client not mentioning anything about birds nesting in the home, bird mites did not seem likely. But the claim about bat mites caught me off guard.  Over the past few years I've had many callers ask about bird mites, but never bat mites. I wondered if there even was such a thing?  I could conceive of bats possibly overwintering in a chimney or attic of a home, so perhaps a winter infestation of mites is possible?  In searching my medical entomology and structural pest control books, the only reference to bat mites was Mallis' Handbook of Pest Control.

Mallis cites a single report of bat mite dermatitis published in a 1973 Journal of Medical Entomology. The report described an old rural home in northern California infested with bats. A baby in the home suffered from a chronic dermatitis on the face and abdomen.  Investigators found the child was being bathed on a sink where mites were visibly evident, next to a wall infested with Mexican free-tailed bats. Adults and an older child in the house were not bitten. Once the child's bathing site was changed, and bats eliminated from the home, the biting problem stopped. The mite species was Chiroptonyssus robustipes, whose sole host appears to be the Mexican free-tailed bat.  This was clearly an unusual situation, and one never since reported in the medical or pest control literature that I can discover. My medical entomology textbook notes that bat mites rarely bite humans, and when they do it is usually zoologists handling infested bats or otherwise working in caves among mite-infested bat colonies.

Bat ticks are not uncommon in homes where bats are active or
have recently left the structure after breeding. (Courtesy Iowa
State University)

Complicating things a bit, a colleague pointed out to me that ticks are also associated with bats. Ticks are related to mites, but larger and always parasitic. The bat tick, Carios kelleyi, is a soft tick (1/8-3/8 inch-long) and, according to an Iowa State University publication, is routinely found in bat-infested homes in that state. It is found throughout the U.S.

Ticks in the U.S. are classified as either hard ticks (family Ixodidae) or soft ticks (family Argasidae).  By far the most common human biting ticks are hard ticks, like the deer tick and brown dog tick. Soft ticks are less commonly encountered by humans and are mostly parasites of birds and bats.  They have a leathery, folded cuticle that resembles a crushed felt hat when seen from above. Carios kelleyi is of some medical concern as it has been reported to bite humans and is known to carry at least three types of pathogens, including Borrelia species, the causative agents of tick-borne relapsing fever.

I've never had a bat tick sent to me for identification, nor heard of a human bitten by a bat tick. My colleague Richard Pollack with Identify.us.com commented that each bat tick he has received was misidentified by a professional who "should have known better". Several were PMPs, but one was a veterinarian (who thought the tick was a tapeworm segment), and a doctor who thought "it was some kind of alien being".  I hope readers of this blog will be better equipped when one of these strange critters shows up.

According to a review by Loftis et. al (2005), documented cases of bat ticks biting humans are rare with only one verified U.S. case, in Iowa--and probably the reason that the only state with an extension publication on these ticks. The solution for a bat tick infestation is removal and exclusion of the bats, along with application of residual dusts and/or sprays in suspected roosts and points of entry into the home.

Which brings me back to my email query from the worried Texas homeowner.  Given the rarity of bat mite or tick infestations throughout the country, and even greater rarity of human bites from these arachnids, its doubtful that this case was correctly identified by the PMPs involved. Because no mite or tick could be produced, it's more likely that this was not a true pest problem, and no pesticides should have been applied.  However, when called out on cases like this, it's especially important for the PMP to eliminate all possibilities, including nest parasites (mites and ticks) of birds, rodents and other mammals, including bats.

When faced with mystery bugs in a home or office situation, keep the following in mind:

• Sticky traps can capture mites and ticks and should be used in all areas of the house where the customer believes that suspected "bites" are occurring.
• Take the possibility of mites seriously by inspecting the structure for signs of wildlife or rodent entry. Recommend closing, or using one way doors, any suspected entry points.
• If no evidence of wildlife is present, and no specimens of mites, ticks, fleas, bed bugs or other biting pests can be found, it's generally best to not apply pesticides.  Explain that your company follows IPM principles and that you try to avoid unnecessary applications of insecticides for the sake of your customers and the environment.

A professional knows how to deal with both the common scenarios, and understands something about the uncommon possibilities, like bat mites and bat ticks.

Brits have mystery bugs too

Mites, like this rodent mite, are often blamed for mysterious
"bites" by sufferers of delusions of parasitosis.  But real mites
are rarely found in such cases.

A British weekly cultural and current affairs magazine, The New Statesman, yesterday published an article by a physician, Phil Whitaker, on his encounter with a delusional parasitosis patient.  I found it interesting because the description of how he handled a sufferer of delusions of parasitosis, a not-uncommon condition encountered by PMPs here "across the water" in the U.S.

Delusions of parasitosis is a mental illness in which the sufferer complains of non-existent insects or mites crawling on their skin, biting, or burrowing into their bodies.  In the past a clinical symptom of the condition was frequently referred to as "the matchbox sign". This came from the observation that sufferers often carried to the pest control professional, or physician, a small matchbox supposedly containing samples of a parasitic insect that was making life miserable.  Today, it's more likely to be a ziploc bag or plastic pill jar, or pieces of tape on a sheet of paper carrying the mystery samples.

The only point in his article on which I would disagree with Dr. Whitaker is the frequency, at least here in the States, of delusional parasitosis. He calls it rare. Based on stories I hear from likely delusional patients, I don't think it is. If I can believe half of the stories, doctors--at least here in the big city, Dallas--seem to be pretty aware, and a little gun shy, of anyone coming into their office complaining of "invisible bugs".  From my perspective it seems like the medical community could better help these patients by being better informed of the illness and of the available treatments.  This is a serious and highly disruptive mental illness, and one that often leaves pest management professionals confused and frustrated.

Our role in the pest management field is, of course, to take all complaints of biting pests seriously.  After all, our expertise is, or should be, to be very familiar with all biting pests likely to be in a home. Bird and rodent mite calls seem to be more common this year than ever before, a situation I blame on some very bad information being promoted on the Internet.  To learn more about biting mites, what they can and can't do, check out my biting mites in homes fact sheet.  And for a more general publication to share with customers who complain of mystery bugs, click here.

When customers' delusions affect their pets

Long-time readers of this blog, or you who hear me talk at pest control conferences, know that I occasionally address the subject of delusions of parasitosis.  This is one of the trickier "pest" problems to solve, especially since there is no pest involved.  In my office I receive 2-3 suspected delusional samples per month, many as referrals from some of you.  The problem seems worse this year, as I have had many people convinced that they have intractable biting mite problems after reading misleading and harmful information online.

A recent article published in the Veterinary Information Network News Services addressed the issue of pet owners bringing their pets in for treatment of non-existent bugs. Apparently PMPs and vets both have to deal with this issue, and I found the article informative and helpful. One story, highlighted in the accompanying photo, had a happy ending when the client accepted psychiatric treatment. Sadly, it is very difficult to get most delusional clientele to pursue such therapy.

Some of these folks perceive normal grooming behavior of their pets as proof that the pet is infested and suffering. I guess the lesson here is that in cases where you cannot detect a valid pest, and the pest description doesn't match reality, take everything a customer claims with a grain of salt.  For more information on diagnosing mysterious bug bite cases see my factsheet.

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.

CDC publishes Morgellon's Study

Skin lesions and fibers on patients with unexplained
dermopathy. (from  Pearson et al. PLoS ONE)

Yesterday the Centers for Disease Control officially released their long-awaited study of people suffering from a condition that has come to be called Morgellons.  Preferring to use the term "unexplained dermopathy," researchers provided no scientific support for the condition, leaving open the possibility that many such cases may be psychological in origin.

While the conclusions of study may be shocking to members of the media, public health experts and entomologists who regularly see people with non-existent bug problems are not surprised. A smaller study published last May found no connection between similar unexplained dermopathies and skin parasites.  And professional entomologists who regularly interact with the public are very familiar with samples of supposed biting insects and far-ranging descriptions pests that fit no profiles of real insects or mites. As I discussed in a post last year, some of these samples come from people with a special kind of delusion called delusory parasitosis, while others come from people experiencing allergic reactions, drug side effects, or other medical conditions. All of these can produce sensations closely resemble tiny bites or creeping sensations on the skin like a plague of bugs.

In recent years, some people with these unexplained skin conditions have sought an alternative explanation for skin lesions and the accompanying itching sensations.  The name Morgellons is a lay term supposedly originating from an obscure 1690 reference in a medical monograph referring to a similar condition of the time called "the morgellons." Though the condition is poorly defined, it usually involves seeing unidentified fibers associated with the skin, and many feel it is related to some as-yet-undescribed parasite.

The findings of this week's study in the online journal PLoS ONE, include:

• Approximately 50% of patients who underwent clinical examinations had fibers in or on skin lesions (open or crusted sores). However, when the fibers and other particles collected from participants were photographed and analyzed, they were found to be either hairs, cellulose, or polyester.  There was no evidence that the fibers preceded the lesions, caused the lesions, or occurred in normal skin.
• Evidence of prior drug use (i.e., from amphetamines, barbituates, benzodiazepines, cannabinoids, cocaine, opiates or propoxyphen) was found in 50% of clinical participants.  Drug use could account for some cases of unexplained dermopathy--formication (the sensation of tiny bugs, like ants, crawling on the skin) is a well-known side effect of drug use withdrawal.
• Over 75% of case patients reported some exposures to solvents through hobby activities. The  prevalence of such exposures among the healthy adult population in the U.S. is unknown and not enough data on type and duration of solvent exposure was collected to draw conclusions.
• The rate of functional impairment and disability found in case-patients was higher than the general population and similar to that detected among people with serious mental illness.

Prevalence of cases with Morgellons-like symptoms was low in the California study group, approximately 3.65 cases per 100,000 people (or one in 27,000 people).  While being the largest, most comprehensive study of  unexplained dermopathy to date, the study had limitations.  It lacked a control group and was mainly descriptive in nature.  Nevertheless the researchers say that they could find no unifying of definitive cause of the condition among people reporting Morgellon-like symptoms. The authors were unable to confidently say whether unexplained dermopathy represents a new medical condition or is another manifestation of delusory parasitosis; however a peer review panel concluded that in the absence of a single, well-described, published case with fibers emerging from intact skin, "it will be difficult to justify the resources needed to start a new study."

Ultimately this study will not end the debate over unexplained dermopathies, like Morgellons. People who believe they suffer from the condition will point to the inability of the researchers to definitively say that "there is no such thing." Dermatologists, physicians and mental health experts will point to the lack of evidence for the condition, the innocuous origin of the "fibers" seen in Morgellons cases, lack of any parasites in skin biopsies and data that suggests a correlation of the condition with psychosomatic illness and drug interactions.

The study concludes with the recommendation that, given there is still no definitive explanation for unexplained dermopathy, sufferers may benefit from standard medical therapies or those recommended for treatment of delusory infestations.  For sufferers of the latter I find the recommendations of Misha Heller and colleages especially humane and sensible. In their letter published in the Archives of Dermatology, they note that the most important step toward successful treatment of delusional patients is developing a strong doctor-patient relationship of trust.  Without adequate rapport, they say, patients are unlikely to comply with prescriptions for anti-psychotic medications, which can make all the difference in the life of someone suffering from delusory parasitosis.

All of this can be baffling to pest management professionals. After all, we're not doctors, nor are we trained to diagnose medical or mental health conditions in patients. Nevertheless, this is an issue that affects nearly all of us at some time over our careers.  When you encounter a customer who claims to have Morgellons, or who points to tiny pests that can not be seen, it's important to stick to what you know.

• Don't allow yourself to be persuaded to apply unnecessary insecticides to control insects that cannot be detected or do not exist. 
• Advise your customer to seek medical assistance for bite-like symptoms (Keep in mind, however, that many doctors are not well informed about pests or even delusory parasitosis. If you know a local MD or dermatologist who is informed about this condition, refer them). 
• Inspect the home, making use of sticky cards and pitfall traps, to ensure it is free of bed bugs, biting mites, and other biting insects. Remember, providing a customer assurance that their home is pest free can be as great a service as pest control itself.

Morgellon's syndrome and delusions of parasitosis

Typical sample from client with non-existent bugs.

A few years ago they came in matchboxes.  Today they're more likely to come in pill jars, Ziploc bags or on pieces of Scotch tape.  I'm talking about samples of nearly invisible items that clients believe are biting or crawling over their skin.  Though it's true that there are some tiny insects and mites that can bite or parasitize people, more frequently these samples turn out to consist only of lint or skin scrapings or insects that would never bite a human.

Most urban entomologists or pest management professionals who have been in the business long enough  know what I'm talking about. There are a surprising number of people seeking help from PMPs or entomologists, convinced that they are being bitten by non-existent bugs.  Some of these unfortunate clients suffer from an allergy, environmental sensitivity, medical condition or drug reaction that resembles a creeping or pricking sensation on the skin.  These good folks have a real medical condition, but are falsely persuaded that insects or mites are involved.

Other clientele are likely suffering from what doctors call a dermatopsychiatric condition, or somatic delusion--technical jargon for a mental illness that causes someone to believe and feel infested by bugs or other animate or inanimate objects.  The problem is common enough to have a name, "Ekbom's syndrome" or "delusions of parasitosis".

I don't know what percentage of the people I encounter each year are (in cases of physical conditions) illusional versus (cases of mental illness) delusional; but I have become convinced based on a variety of similarities and resistance to diagnosis that a high percentage fall into the latter group.

A diagnosis of delusional parasitosis is always resisted and often resented by sufferers. No one wants to hear that a very large problem in their life is psychosomatic.  Indeed the psychological definition of a delusion is "an unshakable belief that cannot be corrected by reason or logic, and which is inconsistent with a patients' intelligence, education or cultural background."  Even family members often find it hard to accept that their loved ones are suffering from a psychosomatic problem.

A paper published earlier this week by Sara Hylwa and colleagues at the Mayo Clinic in Rochester, MN represents one of the first published efforts to take a serious and critical look at specimens and skin samples from people who had been diagnosed with delusions of parasitosis.  A total of 108 patients previously diagnosed as delusional were included in the study. None of the 80 skin biopsies from these patients provided any evidence of skin infestations of any sort (including scabies).  Ten actual insect specimens provided b patients were assessed and 9 out of the 10 were determined to pose no risk of skin infestation (one was a pubic louse).  Most of the samples consisted of skin debris, environmental detritus, or plant material.

These findings are consistent with what I have observed for over 20 years as an extension entomologist.  During this time I have looked at perhaps 2 to 3 samples a month that turn out to not be insects. Encountering a delusional client is frustrating because, as an entomologist I can often recognize the problem; but there is little I can do to treat or solve it, short of educating caregivers. 

The Mayo study represents the first of two highly anticipated reports on this problem by medical researchers.  A second study is due out in a few months.  According to an article by Melissa Healy in the L.A. Times, this second study, being conducted by the Centers for Disease Control and Prevention working with Kaiser Permanente of Northern California, was launched in January 2008 after patients and a small group of medical professionals led by an organization called the Morgellons Research Foundation advocated for a full-scale government investigation of their symptoms.

The Morgellons Foundation was formed by an online community of people resistant to the suggestion that biting problems can be psychosomatic.  They believe that there is a third possible explanation for cases where bugs can't be found--some mysterious underlying condition that causes the suffering of many or most people today being diagnosed as delusional.

I would, in some ways, be relieved to find out that there really is some organic cause for the suffering I see in many of the people who pass through our office doors each year. It would allow me to give such clients and their families hope that there's a non-psychological explanation for their torments.

I'm not overly optimistic, however. Mental illness is consistent with the irrational and compulsive behavior often exhibited by the bearers of empty matchboxes and Ziploc bags.  Often these folks will provide contradictory and illogical descriptions of their problems.  And the compulsive self-treatment, discarding of furniture, and extreme behavior to escape their insect pursuers is not normal or healthy.

As a PMP there are a few things you can do. 

• If the client cannot produce a likely specimen, use sticky cards around the home. Give the cards a week or so to trap anything suspicious. 
• Check the premises for signs of rodent or bird infestations.  Mites associated with bird and rodent nests can bite people, though they will not hitchhike or live on humans.
• Keep an open mind and take complaints seriously, but don't be pushed into making applications of pesticides that you cannot justify.
• Encourage the cliente to seek a medical opinion, pointing out that sensations of biting or creeping can be caused by things other than arthropods.  Be sure to include a family member or caregiver in the conversation if you can.
• Don't diagnose someone as delusional.  That's a judgment that can only be made by a health professional.  You are, however, knowledgeable about insects--likely more than the average doctor.  Stick to what you know.
• Don't forget to make use of third-party information when communicating with the client or with family members.  I have written a factsheet on Diagnosing Mysterious "Bug Bites" for this purpose.  Beware of information gleaned from dubious sources on the Internet--there is a lot of false and misleading information on this subject online.