Bed bugs, the CDC, and insecticides

The CDC released a Morbidity and Mortality Weekly Report a couple of weeks ago of interest:

Acute Illnesses Associated With Insecticides Used to Control Bed Bugs — Seven States, 2003–2010

Since not everyone is the kind of nerd that thinks reading a 10-page technical CDC report is a fun dinnertime activity, I thought I would give ya’ll a summary.  Basically, the report analyzed data from what’s called the SENSOR system–state public health folks and poison control offices report certain categories of injuries and occupational hazards to a national database.

There is a clear increasing trend of reports of “acute illnesses” over time–over 50% of the injuries happened in the 2008-2010 time period, which nicely parallels the way both cases of bed bugs and media coverage of bed bugs have increased.

The good news is there were only 111 reported cases of people being injured by pesticides while trying to control bed bugs; and only one fatality in the 8 year period studied.   The bad news is that that is almost certainly a major underestimate of the real numbers of people injured:

“Case identification in SENSOR-Pesticides relies on a passive surveillance system, so persons experiencing minor symptoms who do not seek medical treatment or advice from poison control centers are not reported to the system. Second, cases might have been excluded if insufficient information was provided …to determine that the insecticide was used for bed bug control (e.g., surveillance systems do not systematically capture whether insecticides are used for bed bug control). Cases were identified only if available narrative information contained the term “bed bug.” 

Given that people might not seek treatment, or that they may not mention bed bugs specifically, I suspect the number of cases in which folks have gotten sick is much larger.

The other bad news is that the main reason that people got sick was “excessive insecticide application.” Only 2 of the 111 cases involved professional, licensed pesticide applicators.  (One case involved an *unlicensed* applicator, who later plead guilty to a felony.)  In nearly all the cases where people got sick, they were trying to do their own pest control, and/or failing to follow basic safety and application instructions.

The case in which there was a fatality is a tragic example of people panicking over bed bugs and making really, really bad decisions:

“The one fatality, which occurred in North Carolina in 2010, involved a woman aged 65 years who had a history of renal failure, myocardial infarction and placement of two coronary stents, type II diabetes, hyperlipidemia, hypertension, and depression. She was taking at least 10 medications at the time of exposure.

After she complained to her husband about bed bugs, he applied an insecticide to their home interior baseboards, walls, and the area surrounding the bed, and a different insecticide to the mattress and box springs. Neither of these products are registered for use on bed bugs. Nine cans of insecticide fogger were released in the home the same day. Approximately 2 days later, insecticides were reapplied to the mattress, box springs, and surrounding areas, and nine cans of another fogger were released in the home. On both days the insecticides were applied, the couple left their home for 3–4 hours before reentering.

Label instructions on the foggers to air out the treated area for 30 minutes with doors and windows open were not followed on either day. On the day of the second application, the woman applied a flea insecticide to her arms, sores on her chest, and on her hair before covering it with a plastic cap. She also applied the insecticide to her hair the day before the second application. “

The woman was taken to the hospital unresponsive and died.
This is very much the stuff Darwin Awards are made of–but it’s also important to understand why that crazy scenario happened. If you were an ill, bedridden woman being constantly bitten by bed bugs, you might very well flip out to the point where drenching yourself with household flea spray seemed like a good idea.

Ok. Maybe not.

That woman died from pesticides and bad decisions, yes. But she also died because of inadequate education about bed bugs and how they can and can’t be controlled. She may also have died because she couldn’t afford to employ a professional, licensed pest control company or applicator, which can be very expensive.

There is a reason that people do what are, frankly, really stupid things like overuse pesticides or use them off-label.  They are freaking out and really unhappy about their bug problem. Bed bugs can be difficult to control, and are notorious for needing multiple applications before they are truly exorcised from a house.  There are several reasons for this, some of which is just behavior unique to the nature of the little buggers. Bed bugs don’t live out in the open where they are easy to kill.

Once you are on your second…or third…or fourth cycle of trying to kill the bugs, I can see why using more pesticides, or new ones that might not be labeled for that purpose, might begin to seem like a good idea to a desperate person. It is NOT a good idea. People can get hurt, as the less dramatic cases demonstrated.

Other really bad ideas of note mentioned in this CDC report:

  • Using DEET in mass quantities as an insecticide. It won’t kill insects, it’s a repellent.
  • Using an agricultural pesticide inside a house (That’s the case that led to the felony conviction).
  • Not telling anyone else (co-workers, neighbors, etc.) that you just applied lots of pesticide and they should avoid contact with it.

More and better education about bed bug biology, and ways they can be controlled safely, would help people make better decisions.  Most health departments and State Extension offices are stepping up and working on that, and there are great online resources as well.

If you are battling bed bugs: PAUSE, take a deep breath, and read the instructions carefully before applying something.  You’ll get better results in the long run, and won’t hurt yourself or others. Don’t be afraid to ask for advice–and make sure the advice comes from someone who isn’t trying to sell you something.

Generally, we have better and safer pesticides available to us now than we’ve ever had in human history. But that doesn’t mean that they are completely without risk to humans or pets when applied in ways they weren’t meant to be used.

Bedbugs and Pesticide Resistance

I discovered that bed bug evolution–specifically resistance to pesticides–was also the subject of the National Evolutionary Synthesis Center‘s podcast this month.  A FASCINATING interview with one of the grand old men of evolutionary genetics, James Crow.  He worked on DDT resistance back in the late 40s and 50s.

There is also a wonderful accompanying article at Understanding Evolution.  And, they repeat something that I’ve tried to explain in the past:

“Like pyrethrums, DDT kills insects by acting on the sodium pores in their nerve cells — and it just so happens that many of the same mutations that protect an insect against DDT also happen to protect it from pyrethrums. When DDT was first introduced, such mutations were probably extremely rare. However, with the widespread use of DDT in the 1950s and 60s, such mutations became much more common among bed bugs through the process of natural selection. Though DDT is rarely used today because of its environmental effects, these mutations have stuck around and are still present in modern bed bug populations. Because of the action of natural selection in the past (favoring resistance to DDT), many bed bug populations today are primed with the right sort of genetic variation to evolve resistance to pyrethrums rapidly.”