Wednesday, December 19, 2012

Pest Prevention by Design

Imagine a community where the newest buildings were pest resistant. It would be a place where architects and engineers worked hand in hand with pest management experts to take pests into consideration during building design and construction. Foundations of these new buildings would be reinforced with termite barriers, kitchen walls could be opened easily for inspection and treatment, access points to electric utility chases would be easily reachable, exterior doors and utility penetrations would be rodent-proof, and birds would find few easily accessible perches or nesting holes. Now imagine schools and government buildings, homes and shopping centers with features that greatly simplified pest control and reduce the need for pesticides.

That's the idea behind the new Pest Prevention by Design Guidelines published this month by San Francisco Environment, a department of the city and county of San Francisco, CA. The principal author and leader of this effort is Dr. Chris Geiger, a trained entomologist and Urban Pest Management Program Manager for the City and County of San Francisco's Department of the Environment. I love Chris' up-front and down-to-earth admission in the report:
"The world is blessed with many charming, pleasurable, glamorous and enticing subjects on which to ponder. Pest management is not one of these."
How true. But of course a world without pest management would be unlivable too.

The format of the report is clean and easy
to follow. The recommendations are based
around 18 building features, and cite technical
references for the guidelines where they exist.
The new publication was and is a team effort, involving a Technical Advisory Committee that included pest management experts, PMPs, architects, and engineers. Universities in the mix included Cornell, Penn State, Texas A&M, UC Davis and Riverside, and the NJ Institute of Technology. The National Pest Management Association was involved, as well as several pest control companies.  My point is, this is not just the wild imaginings of some California tree-huggers (apologies Chris), but a serious effort to start a dialogue between us in the pest control industry and the folks who build both green and not-so-green buildings. The project was funded by the Centers for Disease Control.

I think anyone with an interest in the subject of pest proofing, owes it to themselves to take a look at the report. The authors limited the scope of the document to commercial buildings, and it is far from a perfect or complete document, as the writers will admit. But it's a start.

Looking forward there are several hopes for this project. First, we intended it (yes, I was involved too) to serve as a starting point for better dialogue with architects and engineers--two groups that historically have not been very interested in pest control.  With the current interest in green or sustainable buildings (IPM is actually a part of today's LEED green points rating system) it appears that the time may be ripe to entice these folks to take pest control more seriously. Consider that built-in pest control should mean longer useful lives for buildings, more pleasant and livable indoor environments, cleaner air and less need for pesticides--all admirable green goals.

Second, we hope that the guidelines will be referenced by green building advocates, builders of schools, those in the apartment and hospitality industries, and government officials wanting to reduce the long term maintenance costs of public buildings.  After all, pests are  frequent contributors to building decay and decline--an expensive problem for all.

Last, we intend these guidelines to be a living document. Ultimately it is intended to reside as an editable database, where suggestions and revisions can be made over time. Once a suitable web home is found, it will be easy to update and improve. If, as you read through the document, you see things that can be added or improved, we want to know about it.

I can hear grumbling by some that "if we build pest proof buildings there won't be any work left for PMPs". That I seriously doubt. It's my personal belief that as long as there are people living in buildings, there will be plenty of pests. I think that what this effort does is raise the status and profile of pest management into more of a science and less of a fire station mentality (constantly putting out preventable fires). There will be a need for PMPs to get involved with the building planning and execution process. Yes, if this concept catches on, there might be less for PMPs to do in these newer and greener buildings; but the lost jobs will be the kinds of problems that no one wants anyway--those institutionalized, chronic pest problems that seem to never go away because of filthy conditions or rundown facilities.

As for me, I know I'd rather live in a condominium or apartment, or stay at a hotel, or eat at a restaurant that was built with IPM in mind. Wouldn't you? And that's what pest prevention by design is all about.

Thursday, December 6, 2012

Entomology in Knoxville: Bed bugs, Ants and Others

Bed bugs remained one of the most frequent subjects of
new research reports at the annual ESA meetings.
Continuing my earlier report on goings on at the Entomological Society of America's annual conference...

Total release foggers

In addition to health-related papers, urban entomology sessions covered many practical aspects of pest control. North Carolina State's Coby Schal, one of the top guns in urban entomology, reported on the first field study of total release foggers (bug bombs) for cockroach control. You may have heard of a parallel study done this year by Susan Jones at Ohio State University. She conducted a set of laboratory experiments with total release foggers (TRFs) against bed bugs, the results of which she recently spoke about on PCT's multimedia website.  She found that field collected strains of bed bugs were essentially immune to three common over-the-counter pyrethroid TRFs, and that even highly pesticide susceptible lab strains were largely able to survive when give basic cover as simple as a piece of paper.

Schal pointed out that TRFs are frequently misused by the public, causing four to eight home explosions per year in New York City alone. His lab looked at the impact of two TRFs on both naturally occurring cockroach populations and on "sentinel" cockroaches (lab reared cockroaches contained in open, escape-proof containers) placed in multiple locations in the treated apartments.  While the foggers did kill the pesticide-susceptible, lab-reared cockroaches, they provided little to no control of wild cockroaches (with 200-fold resistance to pyrethroids). In some treated apartments wild cockroach populations actually increased during the test. It will be interesting to see if the U.S. reevaluates registrations for TRFs in the next few years given the safety issues and dismal data coming out of university labs around the country concerning their use.

Bed bug repellents?

Conventional wisdom suggests that there are no repellents that can be sprayed on the skin to prevent bed bugs from taking a blood meal. However Changlu Wang, of Rutgers University, says "not so fast". He looked at the problem from a different angle, pointing out that there are two possible uses for repellents. Besides the traditional use of repellents applied to the skin to keep insects from biting, repellents may also be used off-host to keep bed bugs from climbing onto beds, suitcases, or other inanimate objects.  

Wang and colleagues looked at this second use. They chose several repellents including DEET, permethrin, picaridin, isolongifolenone, and other potential repellents. Although several products showed repellency, DEET was the overall winner. At 10% and 25% concentration, bed bugs were repelled from Climbup Interceptors (guarding a table with a CO2 lure) for 9 hours and 2 weeks, respectively.  While the practical use of repellents in the real world needs more experimentation, this is useful information.  DEET could conceivably be used as a repellent on some shoes (it does dissolve some plastics, so user beware) or booties to reduce the risk of hitchhiking bed bugs being picked up by technicians (or researchers!).  I expect that eventually bed bug control will be supplemented by the use of repellents as a quarantine tool or for "push-pull" tactics to get bed bugs to go where we want them to go (say, to treated harborages).  Wang cautioned that bed bug behavior may be different around a host where attraction to a live host may overcome the repellent effects he saw.

Standardized bed bug testing

One of the biggest applied bed bug research challenges today is how to standardize insecticide testing. It is common knowledge that results for nearly any insecticide can be fairly easily manipulated by selecting the right strains and using protocols that show more or less bed bug mortality. The challenge is to find protocols that are more or less predictive of a product's performance in the field. Mark Feldlaufer, with the U.S. Department of Agriculture/ARS, reported on progress being made to verify fair, standardized testing methods. This research will support the EPA in its efforts to develop standardized test protocols.

He noted that there are currently 318 insecticide formulations registered for bed bug control, 90% of which include pyrethroid insecticides. He noted that not all pyrethroids are equal, and cited as an example transfluthrin (currently unregistered in the U.S.). Transfluthrin has a high vapor pressure, which most PMP realize is likely to provide better control in difficult to reach areas like voids and crevices.  He also noted that a new combination product (metofluthrin plus clothianidin) is in the insecticide pipeline for bed bugs.

Among the USDA findings were that male and female bed bugs are approximately equal in insecticide susceptibility. This finding could allow researchers to use only one sex in tests (avoiding mortality problems with  traumatic insemination by males on females) rather than the 50/50 ratio currently recommended. Also, test results did not significantly change after seven days, suggesting that tests could be terminated after this time.

How to classify and handle insecticide exposed bed bugs is an issue for anyone who has conducted bed bug trials. USDA classified insecticide-exposed bed bugs as alive (A), dead (D), or morbid/moribund (M/M).  The latter group consisted of bed bugs that were not completely dead, but did not behave normally or respond normally to probing. They found that if placed on untreated surfaces after exposure, between 7 and 77% of the moribund bed bugs recovered compared to 100% mortality of M/M bed bugs left on treated surfaces. This information should be useful in helping EPA decide how to require M/M to be handled. It is fascinating, and alarming, how slight differences in the way test subjects are handled and classified can dramatically influence test results.

Other interesting reports

  • Susan Jones (Ohio State) reported positive results controlling bed bugs with a new neem formulation (CIRKIL), which, PCT magazine reports, will be available in the U.S. this fall.
  • Joe DeMark (Dow AgroScience) reported on field testing of a new Recruit AG above ground bait station for termites. This product will carry 254 grams (one pound) of bait matrix per station. Of nine sites on which it was tested, all termite colonies were determined to be eliminated within four months.
  • Mike Rust (University of California, Riverside) reported on studies with the Turkestan cockroach, a species spreading throughout the southwestern states (CA to TX). They found that the Turkestan cockroach is better adapted to dry situations than the oriental cockroach, especially at higher temperatures, and may be expected to displace Oriental cockroaches in hot, dry situations.
  • Karen Vail (University of Tennessee) tested insecticides on odorous house ant.  She found fipronil provided slightly superior control to Talstar, and she observed 2-4 weeks control with the new Arilon insecticide (indoxacarb).  She also found that sprays applied with backpack sprayers targeting ant trails and structural guidelines (gutters, ledges, etc.) were as effective in controlling ants as high-volume power sprays.
  • Dini Miller (Virginia Tech) reported that a 2011 National Apartment Association survey found bed bugs as the number one concern among apartment owners (beating out concerns over property taxes). Besides control expenses, additional costs due to bed bugs include carpet wraps (to contain bed bugs on infested carpets during removal), need for heavier duty paint (to better cover fecal spots on walls), delays in rental payments, increased evictions, more abuse from residents, and loss of reputation in the community. Twenty states now have laws addressing responsibility for treatment costs for bed bugs.
  • In a study reported in the May 2012 issue of Infection Control and Hospital Epidemiology, researchers from Nebraska tested the effectiveness of chlorine dioxide gas as a fumigant for bed bugs. You may remember chlorine dioxide as the gas used in US governmental facilities after the 2001 anthrax attacks. It proved to penetrate cracks and crevices well and kill bed bugs effectively. Chlorine dioxide is used in hospitals for germ control and might find a niche use for battling bed bug infestations in medical settings.
  • Margie Lehnert, Clemson University, described a simple but (I thought) ingenious technique for studying bed bug population dynamics. She used nylon stockings inside a HEPA vacuum hose attachment to collect small bed bug aggregations in infested apartments. Once an aggregation is sucked up, the stocking can be removed and tied off and returned to the lab for counting. In this way Lehnert has developed a powerful tool to study population patterns and, perhaps, better infer reasons for bed bug dispersal away from beds. 
  • Chris Keefer, Texas A&M University, presented some of the first data I've seen on the invasive, and difficult to control, dark rover ant. This ant is thought to have entered the U.S. from Argentina in Louisiana in 1978. It is now common through most of the southern states.  Keefer, after some difficulty,  has figured out how to colonize these ants in the lab. Using his lab ants he was able to compare the effectiveness of three baits: Terro PCO gel (98% control), Advance Ant Gel (88% control) and Advance Granular Bait (large granules) (58.81% control). The best residual insecticide treatments he found during an outdoor field trial were Demand CS and Temprid, which gave 84% and 82% control, respectively. This confirms what I've heard some PMPs say about effective treatments for these ants.
Of course much more went on in Knoxville than I can report (curse those concurrent sessions!). If I've done no more than convey how exhausting it is to sit for 50 paper sessions (my count), I've given you a taste of what it's like to be there.  Next year's meetings are scheduled to be in Austin, TX, so I encourage some of my Texas colleagues to consider attending. This year the ESA planned a special event for PMPs, including an ACE prep class. Stay tuned for PMP programs for 2013.

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.