Tuesday, February 16, 2010

Bed bugs got legs

A new study out today by Changlu Wang and colleagues at Rutgers and Purdue University had so many interesting findings, I just have to share them with you.  Wang and colleagues investigated characteristics of the bed bug infestation and dispersal in a 223-unit high-rise apartment building in Indianapolis, Indiana between December 2008 and April 2009.  They used bed bug interceptors, which I've reviewed here before, visual inspections and resident interviews to learn about how bed bugs travel through high density, high-rise apartments.

A few of the observations coming out of this study:
  • In this study, conventional (pesticide-based) pest control monthly treatments for bed bugs was mostly ineffective, though the approach used by the contractor was not explicitly described in this paper.
  • 45% of the 223 high rise apartment units experienced documented bed bug infestations within 3+ years of the initial reported infestation, showing how fast a bed bug infestation can spread in multi-floor housing. 
  • Adult bedbugs were 9 times more likely to disperse out an apartment doorway than nymphs.  Although migration through apartment walls was not monitored, the authors noted that there was no reason to assume that dispersal behavior would be different via that route.
  • 53% of infested apartments were adjacent to another infested apartment, suggesting that direct apartment-to-apartment dispersal is likely, either through walls or hallways.  Surprisingly to me, hallways appeared to be a relatively common highway for dispersal.  The researchers noted an average of six bed bug immigrants leaving infested apartments via the front door per month.  How many of these actually survived to make it to a neighboring apartment was not determined.
  • I think one of the most interesting and significant findings was that 50% of the interviewed residents who had infestations were unaware of the bed bugs in their apartments.  Many people, apparently, either show no reaction to bed bug bites, or attribute the welts to some other cause.  This could explain how bed bug infestations can develop before being noted or reported.
  • The Climbup® Insect Interceptor proved to be a useful tool for monitoring bed bugs, even in rooms with relatively low bed bug populations.  Significantly, the study also mentions use of the monitors with a new bed bug-attractant lure manufactured by Bedoukian Research Inc., a manufacturer of flavor and fragrance chemicals in Danbury, Connecticut.  Wang et al. report that in their unpublished laboratory studies the lure was effective at attracting bed bugs from a 30 cm (1 foot) distance.  Although there are several lures that may be effective at attracting bed bugs from longer distances, an effective solid lure with slow release technology would be a real breakthrough for the bed bug control industry.  According to Izzy Heller, Sales Manager at Bedoukian, commercial availability of their product is at least a year away, as they continue to collect data and explore EPA registration. Keep posted.
  • Interceptors in the study were used under bed posts and next to entry doors of study apartments.  These interceptors appeared to provide some control of bed bugs in addition to providing residents with peace of mind during the extermination period.
I came away with two take-home messages from this paper.  First, any protocol for treating bed bugs in apartments or hotels should, at a minimum, include inspection of adjacent units, regardless of whether the resident has seen bed bugs.  Second, if you are in the bed bug business, or the apartment management business, the Climbup® Interceptor is a nifty, low cost tool for assessment and possibly, to some extent, control.

    5 comments:

    keith said...

    Thanks for passing this information along, interesting observations. I think it was surprising to me that 51% were not aware of the bedbugs. Thanks again.

    Bed Bugs Northwest said...

    Thanks for the great report on some of the new science surrounding bed bugs in multi-tenant housing. After six months of chemical treatments, our building was declared clear by our friendly bed bug sniffing dog. www.bedbugsnorthwest.com

    diatomaceous earth said...

    Monitoring is critical. Are bed bugs at all attracted by light?

    When you were talking about chemical treatments, I thought there might be mention of using DE as an alternative. From what I understand, diatomaceous earth has worked where the chemical army didn't.

    Mike Merchant, PhD said...

    Bed bugs are more repelled by, than attracted to light. DE is certainly an alternative pesticide for control of bed bugs. Advantages include it's low toxicity, low cost, and lack of resistance among bed bugs. I hear good things about DE from both the research and pest control community and suspect it will be an increasingly important tool in bed bug management.

    Nagato said...

    I work in the bed bug business in the DMV ( Washington DC, Maryland, and Virginia) and my studies show the conventional appreach ( pyrethroid pesticides) to be 50/50. The climb-up interceptors help and are pretty comforting to people. For the pesticide treatments, I find if I switch up then I can go the all pesticide route. Steam I find to be a waste of time in a lot of cases. So for me traps and pesticide having been working just fine. Especially one called Phantom.