Dr. Stephen W. Hwang is a research scientist at the Centre for Research on Inner City Health, the Keenan Research Centre in the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, and Associate Professor of Medicine and Director of the Division of General Internal Medicine, University of Toronto. He is lead author of the influential 2005 Toronto bed bug infestations study. Dr. Hwang graciously answered our questions about the recent anemia case report in the Canadian Medical Association Journal which has deepened our understanding of the health effects of bed bugs on vulnerable populations.
New York vs Bed Bugs: Can you tell us about the severity of the patient’s condition and why it was caused by bed bugs? This was a life-threatening condition?
Dr. Stephen W. Hwang: The patient had severe anemia (a very low level of red blood cells) because he had an extensive bed bug infestation in his apartment that had gone untreated for months. This man was losing a substantial amount of blood on a daily basis to the thousands of bed bugs living in his bed and mattress, to the point that he became iron deficient. His blood levels reached a very low level that could be described as potentially life-threatening, although fortunately he did not suffer any permanent damage to his health. As we describe in our report, we are quite certain that the bed bugs were the cause of his anemia because an extensive series of medical investigations did not reveal any other source of blood loss or an alternative explanation for his anemia. In addition, his anemia went away and did not return after his apartment was treated for bed bugs.
New York vs Bed Bugs: The patient’s bed bug infestation has been abated but not eradicated. Presumably he is still at risk should the infestation grow to previous levels. Have you any indications of the prevalence of persistent bed bug infestations in the vulnerable populations which are the subject of your research interests? And what are the implications for the care of individuals who are at higher risk for chronic bed bug infestations? What would you recommend to health care providers?
Dr. Stephen W. Hwang: We have not done a follow-up study to find out if bed bug infestations are more common than before among vulnerable populations such as people living in homeless shelters or residents in low-income housing. In my experience as a physician caring for patients who are homeless, I would say that the problem of bed bugs has become even more prevalent over the last 5 years. Although many people complain about bed bug infestations, and rightly so, I think that the main point of our case study is that we should be keeping our eyes open for those individuals who have bed bugs in their home and are not complaining about it, for whatever reason. I suspect that people who have severe mental illness, addictions, or cognitive impairment (such as dementia) are at highest risk of developing overwhelming bed bug infestations. Health care providers need to familiarize themselves with the symptoms of bed bug bites and infestations, and be prepared to give advice on how to deal with this problem.
New York vs Bed Bugs: Aside from severe allergic reactions, there is little evidence in the medical literature for any of the potential health risks that have been suggested for bed bug infestations. It’s an open question, however, whether there is awareness and capacity to detect effects. In the years since your Toronto survey of bed bug infestations, what has been the interest in and perception of bed bugs in the medical and social services communities?
Dr. Stephen W. Hwang: Over the last 5 years, I think bed bugs have changed from being a new and unfamiliar problem to one that many health care and social service providers are very accustomed to seeing. Since this is a problem that shows no sign of going away, we need to prepare ourselves for a continuous and sustained effort to improve the control of bed bugs, rather than expecting to “defeat” or eliminate them. The risk is that we can’t afford to become either complacent or hopeless in this ongoing struggle. I also believe that we need to devote more resources to ensure that people who don’t have the capacity or resources to deal with bed bug infestations in their home can get the assistance that they need.
Publications:
Pritchard, M.J. & Hwang, S.W., 2009. Severe anemia from bedbugs. CMAJ, 181(5), 287-288. doi:10.1503/cmaj.090482
Hwang SW, Svoboda TJ, De Jong IJ, Kabasele KJ, Gogosis E. Bed bug infestations in an urban environment. 2005. Emerging Infectious Diseases 11(4), 533-538. http://www.cdc.gov/ncidod/EID/vol11no04/04-1126.htm
These pages may be of related interest:
- New case report of severe anemia in a patient with an advanced infestation
- Saturday questions: Usinger’s anemia
- New guidance for bed bugs in health care facilities
- Australian medical entomologists on what GPs should know
- New IPM bed bug manual for homeless shelters and group homes: a Q&A with Jody Gangloff-Kaufmann
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It disturbs me when I see professionals saying that “we need to prepare ourselves for a continuous and sustained effort to improve the control of bed bugs, rather than expecting to “defeat” or eliminate them. “
I feel that this kind of thinking is completely wrong. Our goal absolutely should be to defeat them…period; and it is absolutely doable. All that is needed is chemistry that works. That was the answer in 1946 and it is the same answer today. However, that chemistry must be allowed to be placed in the hands of the general population.
There is an effort under way to allow some products back under something called Section 18; and at the same time they want to make them restricted use pesticides.
There has been a great deal of talk about how DDT and Malathion defeated bedbugs in America, and it is true! However it wasn’t done be pest control professionals. We had a major role to play, but it was accomplished so effectively because the average homeowner could purchase these inexpensive, effective products and do it themselves. That is what makes it work….everyone spraying and everyone killing them in their own homes, even if they couldn’t afford for a professional to do it for them they could still take care of their families needs. If everyone can’t be a part of this control program then the re-infestation rate will continue forever and “we need to prepare ourselves for a continuous and sustained effort to improve the control of bed bugs, rather than expecting to “defeat” or eliminate them. “
There is one more point that I would like to make. If bedbugs carried and transmitted West Nile Virus, the Black Plague, or hanta virus, or any other infectious disease we wouldn’t be having this discussion….we would have those products in everyone’s hand tomorrow. If we continue down this misanthropic path regarding pesticides that day will come. Just because bedbugs aren’t the vector today, doesn’t mean that something else won’t be a vector of disease in the future.
Hi Rich,
Not transmitting disease is the particular genius of the bed bug. But, seriously, I’m not sure that I want to see untrained people have access to potent pesticides. I know what people do with the stuff that is available now. But I think I understand your perspective.