Of birds and bats: histoplasmosis and human health

A recent report from the Centers for Disease Control should remind us of the importance of managing urban bird and bat populations. In the December 19 edition of the Morbidity and Mortality Weekly Report (MMWR), there is a report about a Pennsylvania-based, church mission group who had been renovating a church in Nueva San Salvador, El Salvador. It turns out that as part of the renovations involved cleaning and sweeping around some bird and bat roosting areas. Nine of the 11 persons with the initial group returned home with flu-like symptoms. The symptoms were eventually diagnosed as histoplasmosis, a disease caused by inhaling the spores of a fungus, Histoplasma capsulatum. Eventually eleven more volunteers from two other missions groups from Pennsylvania and Virginia, working at the same church at approximately the same time (Feb-Mar, 2008), also met the case definition for the disease.

Histoplasmosis is a pest-borne diseases that PMPs often hear about, but rarely encounter (at least knowingly). It is not a disease that requires travel to the tropics. The pathogen is common in the U.S., and the disease is probably more common than most of us realize.

The fungus live in soil, and people typically get infected when they breath dust from soil in areas where H. capsulatum naturally occurs (the term for this is "endemic"). According to NIOSH publication 2005-1009, H. capsulatum is endemic throughout the U.S., although the proportion of people infected by H. capsulatum is higher in central and eastern states, especially along the Ohio and Mississippi River valleys. Fortunately, once contracted the disease is not contagious.

The interesting thing about this disease, from the perspective of the PMP, is that "the fungus seems to grow best in soils having a high nitrogen content, especially those enriched with bird manure or bat droppings." The organism is believed to be carried on the wings, feet, and beaks of birds thereby increasing the risk of infected soil under bird or bat roosting sites or in manure accumulations inside or outside buildings. Some bird species whose roosts have been shown to be contaminated include blackbird (starlings, grackles, red-winged blackbirds, and cowbirds) pigeons, chickens and bats. Some are concerned that growing problems with Canada geese could also be contributing to spread of the disease to people.

Because the fungus cannot infect birds, there appears to be little risk of contracting this disease from bird droppings on window ledges or inside buildings. It's only when these droppings contact infested soil, that the fungus is able to spread and become a health risk.

Bats are a different story because, according to the CDC, they can become infected with the pathogen. So bat droppings can be potential sources for infection.

How bad is it?
Histoplasmosis symptoms vary greatly. Most people who contract the disease show no, or only mild symptoms. In some of us, histoplasmosis will result in flu-like, respiratory symptoms, including including a general feeling of illness (malaise), fever, chest pain, dry or nonproductive cough, headache, loss of appetite, shortness of breath, joint and muscle pains, chills, and hoarseness. In some cases, the disease can become chronic and result in more serious complications, even death.

Histoplasmosis may not be one of the most serious diseases we will be exposed to during our lifetimes, but because it is rarely diagnosed, it probably causes more lost work days that we realize. And it is certainly able to make us sick enough to miss work.

What should PMPs do?
The first concern of a pest management professional who encounters bird or bat infestations is to take steps to reduce the risk of breathing H. capsulatum spores. When working in dusty areas with bird or bat droppings, a good respirator should be worn. All it takes to cause infection and subsequent development of histoplasmosis is a brief exposure to inhaled contaminated dust. Remember that not all air filtering devices are equal and "people have developed histoplasmosis after disturbing material contaminated with H. capsulatum despite wearing either a respirator or a mask that they assumed would protect them." For detailed information about different respirator types and when they might be needed, see the NIOSH guide section on respirator protection.

In addition to breathing protection, disposable overalls are recommended by the CDC. This reduces the risk of worker and family exposure to dust that settles on clothing during exposure to contaminated soil.

Knowing how to protect your customers is also critical here. In areas where public access is minimal, or where remediation of droppings is taking place, the posting of signs warning people about histoplasmosis risk is a prudent first step. Anywhere that bird droppings sit on soil should be considered a high risk site for histoplasmosis. The public and unprotected workers should also be restricted from any areas with bat guano accumulations.

Areas that are being cleaned up should be sprayed with water to minimize dust movement. Obviously bird and bat control, and modification of the roosting environment are critical elements in reducing the long-term risks associated with this disease and others.

Histoplasmosis is only one disease risk caused by bird and bat roosts around human activity areas. While we shouldn't fear or loath birds and bats in natural settings, management of their roosting areas in urban locations are an important part of what our industry does.

Making the most of pest control's "dog days"

Historically the term "dog days" refers to the hottest, most sultry part of the summer. According to Wikipedia, the term was first used by the Greeks and Romans (who called this period caniculares dies-- literally, days of the dogs) after Sirius, the "Dog Star", the brightest star in the heavens which becomes visible each year around early July. For the ancients the dog days marked an evil time "when... wine turned sour, dogs grew mad, and all creatures became languid." In modern usage, "dog days" also refers to a slow, unproductive time of year, or as the Random House Dictionary puts it, "any period of quiescence [resting, or inactivity]".

By the latter definition, January is surely the "dog days" of the pest control business. As I sit inside and watch the freezing drizzle out my window, it's hard to remember how busy we all get during the termite, ant, spider and scorpion season (though cockroaches don't seem to care what season it is).

Nevertheless, there's plenty to do right now. This is, after all, one of the best times of year to get yourself re-trained, and to invest in the professionalism of your employees. Next week one of the best training opportunities of the year for those of us in Texas will take place in College Station at the 63rd annual Pest Management Conference and Workshop.

The keynote speaker for this year's meeting is Lloyd Smigel, columnist for Pest Management Professional magazine, motivational speaker and pest control company consultant since 1988. You won't want to miss him or any of the other great speakers and topics next week. The conference traditionally kicks off with the Bill Davis Memorial Golf Tournament on Tuesday (Jan 13), and the sessions run from Wednesday 7:45 am to noon on Friday.

Whether you live in Texas, or Kentucky or California or Florida, make it a point to support your university or association annual training conferences. Yes, it can be expensive to send yourself or your employees for 3-4 days of training at an out-of-town site. But consider the benefits. Some of your staff (perhaps for the first time) will begin to see themselves as professionals, part of a large, important industry. Others will be encouraged when they see the kinds of research being conducted by a large university to answer their questions and help them serve their customers better. All should be inspired by presentations by graduate students who are dedicating their careers and lives to the pest management industry. And if it's available to you (it is at the Texas A&M conference) don't pass up the chance to tour campus research labs devoted to urban entomology research. And last, but not least, among the benefits of these training classes, you and your employees will establish contacts with other professionals, some of whom may become lifelong friends.

One of the things that impresses me most about our industry is how people are willing to share what they've learned with others--including competitors. Knowledge may not be free, but it's available to anyone willing to learn.

Recent ACE Prep Class in Houston

On December 11 I had the privilege once again to participate as an instructor in the 5th Associate Certified Entomologist (ACE) prep class offered in Texas. As with previous classes, the course was sponsored by the Texas Pest Control Association and taught by myself and Dr. Bob Davis of BASF Specialty Products. This class was also co-taught with first-time lecturer Dr. Grady Glenn, pesticide applicator training specialist with Texas AgriLife Extension Service.

As any of the participants will tell you, this is a classic cram course. We cover topics ranging from a brief introduction to entomology and insect classification, to toxicology, laws and regulations and overviews of cockroach, WDI and rodent biology to just name a few. The pace is quick, but fun as the class interacts with instructors and gets a few pointers about test-taking.

The purpose of the class is to prepare participants to take the challenging ACE exam, one of the prerequisites for becoming an Associate Certified Entomologist. At the end of about 6 hours of cramming we offer the exam to anyone who has applied through ESA and registered to take the test that day.

I enjoy teaching this class because of the quality and enthusiasm of the participants, each of whom must have seven years of experience in the pest control business. The other thing I value, and I think participants do too, is the opportunity we have to review fundamentals--the whys behind many of the little rules and facts we learn in pest control. It's a chance to dig a little deeper than the typical CEU class, and much deeper than technician training.

Of course taking the class is no guarantee of passing the test. Our pass rate is typically 50-60%, though this class had a nearly 90% passing rate. We find that success is highest for those who review the study subjects prior to taking the class and exam. But most importantly, we find that the pass rate is 100% higher for those who take the test than those who think about it but never get around to signing up.

If you've thought about certification, but hesitate at the thought of taking a tough exam (it's been a long time for all of us since our last final exam), consider taking one of the ACE prep courses being offered around the state. The next class and exam will be offered at the B&G Chemical and Equipment Company workshop in Arlingtion, on January 22. Note that the Arlington venue is the only B&G venue that will be offering ACE prep training this year.

To learn more about the ACE or BCE certification programs, check out the Entomological Society of America's website at http://entsoc.org/certification. There are no official study guides, but the website offers a very detailed list of the subject matter that is covered by the exam. Two of the best study resources I recommend include the Truman's Scientific Guide to Pest Management, and the NPMA Field Guide to Structural Pests. I suggest focusing study time on topics you feel a little weak in. Stored product pests and pesticide classification are two subject areas where many applicants seem to struggle. Also, definitely take the sample exam on the ESA website. It gives you an authentic taste of what the real exam is like.

Successful candidates receive a certificate and uniform patch and earn the right to advertise themselves as Associate Certified Entomologists. In addition, ACEs receive the ESA Newsletter and have the option to register for ESA journals and meetings at discounted rates.

Congratulations to those of you who recently took and passed the exam. I look forward to seeing many more of you join the ACE ranks in the near future.

Look out for signs of drywood termites

Drywood termites are not a common problem in many parts of Texas, except along the coastal bend areas from Port Arthur to the lower Gulf coast. Nevertheless, drywood termites can show up anywhere in the state. For this reason, PMPs should always be on the alert for signs of these insects.

Drywood termites belong to a different insect family (Kalotermitidae) than the more common subterranean termite (Rhinotermitidae). One of the differences in this family is that all colony workers are immatures, and there is no true worker caste. Another difference is these termite's ability to conserve water and live with no direct soil contact.

One of the best clues that drywood termites are present in a home is the presence of many tiny, six-sided fecal pellets that are ejected from the colony by the termites, or which spill from damaged wood that has been exposed by probing or carpentry activity. The pellets themselves are easier to spot than the ejection holes; but once found, ejection holes can be used as a portal to inject foam or liquid termiticides into infested wood.

Fecal pellets are often less than 1 mm long, and vary in color from light tan to reddish to black. Surprizingly, the color of the pellets seems unrelated to the color of the wood on which they feed. Look for pellets along molding in living areas, when conducting attic inspections, and around window areas. Wings are another sign of drywood termite activity. Look for termite wings in window areas or spider webs in the corners of attics or rooms.

Just because you've never seen drywood termites in your community before doesn't mean they aren't there. Away from the more temperate, humid areas of the state, where they swarm and spread naturally, most drywood termite infestations are imported by humans via furniture or construction lumber. Because these termites reproduce and feed more slowly than subterranean termites, it may take many years for the colony to mature and begin producing swarmers.

Drywood termites are a good example of a pest that may or may not be seen frequently in your area, but one that all pest management professionals should know something about. Keen eyes and an ability to spot things out of the ordinary are skills that will help separate you from your competition.

Bed bugs pose threat to schools?

Some school districts are beginning to worry about bed bugs. About a year ago the Bracken County School District in Kentucky closed their doors for a day to make sure no stray bed bugs were left behind following a find of a single bed bug in classroom. The bug was supposed to have come from a student whose home had bed bugs.

This week the Columbus Dispatch, in Ohio, reports another panic over bed bugs in school classrooms. According to the article, "Researchers and public-health officials fear that tiny, brown, blood-sucking bedbugs are going to spread through schools."

Greg Kesterman, director of the environmental health division for Hamilton County Public Health (Cincinnati, OH, where bed bug problems are growing quickly) is quoted in this week's story as saying, "Anytime an insect has the potential to crawl on a person, and travel with (people), you're guaranteed that you'll see them showing up in a public facility." This is certainly true. Bed bugs have, and will, show up in schools from time to time, especially as infestations in homes become more common.

What I question is the followup worry that steps need to be taken to avoid a "large scale problem" in schools. Are bed bugs really another problem that schools need to be highly concerned about? I doubt it.

While you never want to underestimate nature's ability to cause mischief, the threat of bed bug infestations in schools should be minimal. Bed bugs are principally active in the dark (except in cases of heavy infestations--which would not be the case with the occasional, stealth introduction to a classroom). After dark they need a reliable source of blood to sustain a population and spread. Since people generally do not sleep in classrooms (with possible exception of short afternoon nap times in pre-school rooms), it would be tough going for a bed bug that slipped out of a backpack into a typical classroom from an infested home.

In my estimation there is little risk of actual bed bug infestations requiring treatment in a public school classrooms or auditoriums. Dorms are another issue of course. Also, the risk of one or two bed bugs emerging from of a child's backpack and infesting other kid's belonging is conceivable, but the risk is also probably low. Should PMPs, school nurses and school pest management staff know what a bed bug looks like, and something about its biology and behavior? Sure. Should schools fear they are going to spread through schools and cause a citizen panic? No way.

Cockroaches are far more likely to migrate from a child's backpack and find "Southern Living" in a classroom. And backpack smuggling of cockroaches is at best a minor or occasional source of cockroach infestations in school classrooms.

Report from Reno

Five days and 27 pages of hand-scribbled notes later and I've returned from another Entomological Society of America annual conference. As usual, the meeting was an exhausting marathon of meetings and posters and mixers, sweetened by renewed personal contacts and much new and useful information about entomology and pest control.

Some of the sessions were probably topics only an entomologist would find fascinating, like measurements of insect diversity on Arizona mountaintops, how mosquitoes locate their hosts, or the history of DDT (which cost only $.18/ lb after WWII and even the famous Winston Churchill called "the miraculous powder"!). Nevertheless, there was much information that would be of great practical interest to a gathering of PMPs. Just a few valuable new insights and reports included:

• An update was given on colony collapse disorder (CCD) of honey bees by Diana Cox Fisher, a researcher from Pennsylvania State University, who believes that a combination of stresses and new, or re-emerging, diseases (not pesticides) is probably responsible for the current crisis in bee deaths--at least in the U.S. Currently the best correlation with CCD seems to be a disease known as Israeli Acute Paralytic Virus, although the jury is still out on this one. She noted at the end of her presentation that one out of every three bites of food that we eat is thanks to pollinators like the honey bee.
  
• Several interesting papers were presented on bed bugs. Mike Potter, of the University of KY, noted in his talk on the history of bed bugs, that within 5 years of the introduction of DDT, researcher John Osmun of Purdue University reported that it became nearly impossible for researchers to locate bed bug infestations to study. Tim McCoy, of Virginia Cooperative Extension, noted the importance and effectiveness of dusts as a tool in bed bug control. Tempo dust, Drione, and Tri-die dusts gave the fastest kill of all products (45 minutes to 6 hrs). Boric acid dust was the slowest, requiring over 18 days to kill. Dini Miller of Virginia Tech concluded that hydroprene was a useful additive to conventional sprays for bed bugs (especially resistant populations), though the effects of hydroprene are subtle and may not become evident until the second or third generation.
• One of the most interesting bed bug talks was given by Changlu Wang of Purdue University. He compared spray-based and dust-based IPM programs for bed bugs. The liquid spray tested was chlorfenapyr, and the dust-based program used diatomaceous earth and an innovative bed bug interceptor device placed under bed posts to trap the varmits when they try to climb up, or down from the bed. The clever traps are being sold by Susan McKnight Inc. under the trade name Climbup™ Insect Interceptor. Both spray and dust-based programs worked well in Wang's tests. The traps caught more bed bugs than were observed by the inspectors in all apartments. Another interesting observation was that 94% of the trapped bed bugs were in the outer bowl, indicating that they were off the bed. This shows the importance of treating off-bed locations when controlling bed bugs. These devices might be especially useful for clients with low budgets and a high motivation to help with the elimination program. Of course the effectiveness of the bowls depends on eliminating contact of the bed and bedding with the floor and walls.
• Tom Greene of the IPM Institute (organization running the Green Shield™ certification program for pest control businesses) reported results of a University of Florida study that showed that properly installed doorsweeps can reduce pest complaints in schools by up to 65%. He made an observation that I believe applies not just to school IPM programs, but to all professional IPM: "The question is not 'do you do IPM?', but 'how much IPM do you do?'" Most PMPs say they do IPM, but there is generally much room for improvement of the quality and depth of IPM done by professionals.

New Web Resource for West Nile Virus

In August I posted a story about the human face of West Nile virus. Now there is a website where people suffering from West Nile virus, or others interested in the disease, can exchange information about the topic.

It's called the West Nile Information Exchange, at http://www.westnileexchange.com/, and it provides a forum for folks to talk about the disease and their experiences, or to learn more about research into WNV. The site was developed by Dr. Kristy Murray, an Assistant Professor of Epidemiology for the Center for Infectious Diseases and Associate Director for Research for the Center for Biosecurity and Public Health Preparedness at the University of Texas Health Science Center at Houston, School of Public Health. It has the option for visitors to register and read and post comments about WNV, and subscribe to the comments (like this site).

If you have an interest in WNV, have suffered from this disease or know someone who has, this might be a good place to check out. It's new, so new registrants can help get the discussions going.