Role of DDT in WWII

Little in life is black and white, and nowhere in pest control is this truer than for the insecticide DDT.  Mention DDT in most circles today, and you'll hear "tsk, tsks", and see shaking of heads.  "What were we thinking when we unleashed DDT on the world?"

Yet DDT had its moment in the sun, and doubtless scholars will continue to debate its benefits to humans vs. its environmental shortcomings for years to come.  David Fincannon, a pest management professional and owner of A-All Pest Control in Plano, TX recently published a new video consisting of historical footage and interviews with some of the last surviving PMPs of the Second World War.  In it, these men discuss their experiences with the new insecticide Gesurol, now known as dichloro-diphenyl-trichloroethane, or DDT. Watching this video may not change your mind about the environmental wisdom of DDT use, but it will give you a better appreciation for what DDT contributed to our nation's history. 

I'm so thankful for David's interest in documenting some of the early history of pest control.  One of his key interviewees is Dr. John Osmun, Professor Emeritus of entomology at Purdue University.  Dr. Osmun was one of my favorite professors when I was a graduate student at Purdue. And one of my favorite parts of his class was listening to his many first person accounts of the early history of insecticide development and commercialization. 

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.

Do bed bugs carry disease?

A study just published in the CDC journal, Emerging Infectious Diseases, looks at the question of whether bed bugs might be vectors (carriers) of antibiotic-resistant bacteria.  In scientific parlance this is a great example of a Q&D study (quick and dirty).  The Vancouver, BC researchers had three hospitalized patients come in with bed bugs on their persons.  They thought, "wouldn't it be interesting to test these bed bugs to see if they have any antibiotic-resistant pathogens?"  So they took the bed bugs, crushed them up, and tried to isolate bacteria from them.

It turned out that two of the patients had one bed bug each that tested positive for vancomycin-resistant Enterococcus faecium (VRE).  The third patient had three bed bugs that tested positive for methocillin-resistant Staphylococcus aureus (MRSA).  The authors speculated that the bed bugs may have picked up these bacteria from the low-income community where the patients were from (infections from the two bacteria are prevalent there).  They also hypothesized that bed bugs in this community could be acting as a hidden environmental reservoir for MRSA, and could be contributing to the spread and amplification of MRSA infections in these impoverished and overcrowded communities. 

Such speculations and hypotheses are useful for researchers who love to make guesses and then test their hypotheses through further observations and experiments.  But it is important for those of us in the pest management field to not confuse speculation and hypothesis with facts.  Vector biologists can cite many examples of pests that have been shown to harbor a pathogen, but are not considered to be infectious to humans.  The standard of proof is pretty high for stating that a given insect or animal is capable of spreading infection.  This test does not meet that burden of proof by a mile.  And the authors would be the first to admit it.

So have bed bugs been shown to carry human disease?  Not yet.  In a clinical review published in the Journal of the American Medical Association, entomologist Jerome Goddard and medical doctor Richard deShazo combed the medical literature and could find no strong evidence showing bed bugs to be disease carriers. Based on collections from bed bugs, the hepatitis B virus (HBV) may be the best candidate for human disease transmission by bed bugs; however in an African study, a two-year eradication program that achieved 100% control of bed bugs had no effect on HBV infection rates. The authors concluded that "Although transmission of more than 40 human diseases has been attributed to bed bugs, there is little evidence that they are vectors of communicable disease." 

This is not to say that bed bugs lack health implications for humans.  Goddard and deShazo describe the most common reaction to bed bug bites as "2- to 5-mm pruritic maculopapular, erythematous lesions", medical terminology for "red itchy spots".  These spots usually itch and, "if not abraded, resolve within a week."  Some people, however, have more complex reactions to the bites including rashes and secondary infections.  Also, some people develop severe allergic reactions after multiple exposures to the bites (interestingly, in a 1985 experimental study cited in this review, only 30% of a volunteer cohort showed any reaction to bed bug bites).

In a joint statement issued last year, the Centers for Disease Control and the U.S. Environmental Protection Agency pointed out the emerging health implications of our growing bed bug problem.  In it they addressed the impact that bed bugs can have on mental health, saying, "Bed bugs may also affect the mental health of people living in infested homes. Reported effects include anxiety, insomnia and systemic reactions."  This aspect of the bed bug problem needs more study, and seems to be poorly appreciated by many in the hospitality and pest control industries.

When addressing the medical importance of bed bugs to your customers, it's important to look at the whole picture.  Bed bugs are a public health issue, even though they are not known at present to carry any disease pathogens. It would be unethical to imply that bed bugs are carriers of disease at this time; but at the same time bed bug elimination is important work.  Effective control of bed bugs alleviates anxiety, insomnia and discomfort for your clientele, and maintains a sanitary environment in which to live.  Isn't that what the pest control profession is all about?

Advisory Committee Gets Updates, Homework

The Texas Department of Agriculture's Structural Pest Control Advisory Committee met in Austin last week. I have served on the committee for two plus years, and have written about the advisory committee in the past (search this site for the term "advisory committee").  The committee represents the public and the pest control industry, and meets quarterly to get updates, and offer suggestions and feedback to TDA, on rules and regulations pertaining to pest control in Texas.

Budget Update & Department news

This quarter's meeting included an update on TDA's budget status in the legislature.  House Bill 1(HB 1) (in this session the House takes the lead in drafting the state budget, next session the Senate takes the lead) proposes a 45% cut in the TDA budget.  This seemed incredibly high to me for an agency budget cut, but I wasn't detecting any feeling of panic among Assistant Commissioner Jimmy Bush or other TDA staffers at the meeting.  According to Bush, while such cuts will likely mean a major restructuring of the Agency, TDA does not see any major impacts on the operation of the Structural Pest Control Service (the division of TDA that oversees and regulates the pest control industry in the state).  Much of the cuts being proposed would come from programs at TDA that do not bring in revenue through licenses or fees, namely marketing and the rural economic development divisions of the agency.

The committee was introduced to two TDA attorneys that have recently been assigned to the Structural Pest Control Service.  Mary Luedeker and Lisa Hoyt will take over all new structural pest control cases, working with the agency and with industry to interpret and enforce laws and rules relating to pest control in Texas.   

Legislative Updates

Deputy Assistant Commissioner Dr. Ambrose Charles reported that the Texas Council on Environmental Quality has drafted a discharge permit plan for pesticide applications near water which has been accepted by the U.S. EPA.  He noted that the deadline for implementing this program was recently delayed until October 31, but that there is some question whether this new permitting program will ever go into effect.  He reported that H.R. 872 was recently passed out of the U.S. House of Representatives by a wide margin.  This bill would exempt pesticides labeled under FIFRA from being subject to the Clean Water Act permit system. A companion bill, S. 718, was also introduced into the Senate.  If that passes and both houses agree on a joint version of the bill (there are differences), Congress could effectively bypass the recent court decision that would require permits for pesticide applications for aquatic weed control, forest pest control, mosquito control and other pest control around water. The paperwork and manpower requirements, supporters say, will be expensive to communities and agencies, and will not result in improved water quality.  Environmental groups oppose HR 872, saying it would be a vote for dirty water.  If you have question about how the Texas water permit system works, Dr. Charles is familiar with the provisions of the Texas permitting system.

Katherine Wright-Steele gave a legislative update on four bills relating to the pest control industry that are currently in the Texas state legislative process.  Senate Bill 3, containing language that would repeal all school IPM regulations in the state, has been previously discussed here.  HB 2741, HB 2742, and HB 2743 were introduced by Representative Tim Kleinschmidt, R-Lexington.  All appear to have been introduced with the support of the Texas Pest Control Association.  House bills 2741 and 2742 serve to give TDA more leverage in regulating advertising, restoring some of the authority lost in the last legislative session.  The house bill 2743 seeks to restructure the Advisory committee, eliminating the university (yo!) and department of State Health Services representatives and making six of the nine positions filled by pest control professionals (three would be public members). Status of these bills is still uncertain and there are currently no companion Senate bills.

Wood Destroying Insect Reports

The committee received some homework from Jimmy Bush. Members were asked to review and provide input into the Wood Destroying Insect (WDI) Report (Form No. SPCS/T-4), WDI report inspection procedures (Rule 7.175), and the chapter on WDI inspections in the AgriLife Extension Study manual (B-5075).  This follows discussion from other meetings on ways to reduce the numbers of complaints received each year from the public about WDI reports and inspections.  In 2010 the TDA received 20 complaints related to WDI inspections, approximately 10% of all complaints received.  While some felt that this number of complaints is very low compared to the number of inspections conducted each year, there does seem to be room for improvement.  Improvements to the form itself, as well as the need for improved training and certification for WDI inspectors was discussed. 

A group of industry members (Eric Melass, Mike Dickens and Debbie Aguirre) appointed by the committee late last year  recommended that enforcement of existing rules rather than new regulations was what was most needed. They also suggested that all WDI inspectors be required to carry a certified applicator's license and that CA tests have a section devoted to WDI issues.  If this change did not result in fewer problems, only then should TDA consider creating a special license subcategory for WDI inspectors.

CEU courses

The committee was also charged with reviewing staff recommendations on restructuring CEU course offerings.  A group of SPCS staff reviewed the two existing rules (Section 7.134 and Section 7.135) and offered a draft version of the rules with suggestions for improvement.  One of the most significant concessions in the new version is to allow the use of an online course to meet someone's entire annual recertification requirement.  The only limitation under this proposal would be that online courses could not be used in any two consecutive years to meet CEU requirements.  This is because there is concern that, despite recent improvements in technology, the department is still unconvinced that online courses can fully substitute for face to face training. 

Other changes in Section 7.135 would include eliminating speaker qualification forms, and doing away with a requirement that online course takers pass an exam with at least a 70% to get their CEU credit and be proctored by a certified applicator.  It's not clear under the draft rule how sponsors will guard against abuse of online courses without the proctor requirement.  In public testimony time, Don Ward, Executive Director of the Texas Pest Control Association, expressed the association's general support of online courses if abuse issues can be addressed.  He also expressed a preference for certifying speakers over courses, seemingly the opposite of the new rules.

If you have suggestions for improvements to the CEU or WDI report process, you should contact one of the Advisory Committee members before July 28, or plan to attend the next committee meeting on that date.

Brown widow spiders spreading in California

Brown widow spider with her spiky egg cases.
Photo by Martyn Hafley.

The black widow spider is well known to most pest management professionals. Less familiar is the brown widow, Latrodectes geometricus.  The brown widow is more common in areas where it occurs, though it is reported to be more shy and less prone to bite than its black cousin. Nevertheless, the venom of this species is thought to be at least as toxic as the black widow.

Rick Vetter at the University of California - Riverside reports that the brown widow is showing up at more locations in southern California, and is soliciting samples from that state to document the spread.  In Texas, the brown widow is reported from the Gulf coastal areas from Houston to Corpus Christi.

One of the most distinctive features of the brown widow is its spiky egg case.  The black widow spider makes a tough, spherical egg case without any ornamentation.  The brown widow egg sac is covered with spiky projections.  The spider itself is brown with a yellow or orange hourglass marking on the underside of the abdomen.  The Latin name for the species, geometricus, comes from the geometrically shaped patterns on the sides of the abdomen, patterns that are mostly lacking on the black widow.

The current range of the brown widow is thought to extend in the southeast from Florida to Georgia, South Carolina, Alabama, Mississippi, Louisiana, Texas and Arkansas. It has also been reported from southern California, Nevada and Colorado.

The brown widow is a spider to be respected, if not feared. Vetter calls them "not very dangerous". Dr. G.B. Edwards, an arachnologist with the Florida State Collection of Arthropods in Gainesville, says that the brown widow venom is twice as potent as black widow venom; however, he notes they do not inject as much venom as a black widow, are very timid, and do not defend their web. On the other hand, where they become established, they are likely to be more common than the black widow spider.

I am a hardy promoter of vacuums when it comes to spider control.  Because of their large size and tendency to remain on their cobwebs, Latrodectus spiders may be difficult to control with residual insecticides.  Residual and contact sprays may still be useful in control; but use of vacuums or "Webster" mops to physically remove the spiders and their egg cases is likely to be superior to insecticide use alone. 

If you encounter brown widow spiders in Texas, I would be happy to receive specimens or images of your find.  This will help us have a better understanding of the spread and frequency of occurrence in this state.  Images can be emailed to m-merchant at tamu dot edu.  Or specimens can be mailed in a small amount of alcohol to Extension Urban Entomologist, Texas AgriLife Research and Extension Center, 17360 Coit Road, Dallas, TX  75252-6599.