There’s a really interesting new article in Slate today about bed bugs, co-written by David Johns, a doctoral student in Public Health at Columbia, which examines the question, “How contagious are bed bugs?”
This is really a side note, but refreshingly, Johns points to this Independent (UK) article from 1997 about bed bugs in London hotels, which provides a counterpoint to claims often made by journalists elsewhere that the plague is spreading outwards from New York. I don’t think we have enough evidence yet to know where bed bugs “came from” or if they were equally present in various locations to begin with, and due to complex factors, managed to “spring back” in more than one geographical location at once. However, it’s nice to be reminded that this Reuters headline from London, or this one from IrishCentral.com are not necessarily fact-based. Yes, travel does spread bed bugs, but not just in one direction. There’s plenty of evidence that bed bugs were in Europe as well as the US before the current epidemic got into full gear.
However, the main point here is not where bed bugs came from but how likely we are to get them.
Johns reviews some of the recent research about bed bug transmission and starvation survival rates, and argues that while bed bugs spread easily once introduced into a structure, rates of introduction (or re-introduction) may not be as common as many suspect.
He cites Clive Boase’s study of UK hotels — once cleared, bed bugs did not re-infest the locations within twelve months, even after one hotel had had 100,000 guests.
And Johns cites the New York City schools, where bed bugs were confirmed to be present 3,590 times in schools during the 2010-2011 school year, but were only once known to set up harborages and breed there. (I seriously wonder with how much confidence this can really be stated, but it’s still interesting.)
Johns notes that the recent research study on starvation, by Dini Miller (of Virginia Tech) and others, showed starved bed bugs don’t live nearly as long, unfed, as was once thought.
And he refers to research by Ed Vargo of North Carolina State University on the spread of bed bugs in buildings, where in each of the buildings studied, all bed bugs present in a structure were closely related — suggesting bed bugs were introduced just once into each building, for example, by one pregnant female. Vargo’s assessment quoted here that bed bug “introduction events are probably kind of rare,” is rather comforting.
To a point.
However, the bad news is that,
… as we have learned in other epidemics, the likelihood of transmission depends not just on contact between infected and susceptible individuals, but on viral load.
In layman’s terms, you’re more likely to get bed bugs if there are more bed bugs present — and Johns notes that this means that “the movement of stuff” carrying lots of bed bugs, rather than contact with individual people who might be toting a hitchhiker, is what puts us most at risk of getting bed bugs, because the “dose” — number of bed bugs we’re exposed to — is much greater.
The message that bed bugs don’t spread as easily as some think, and that introductions are relatively rare can only be of limited comfort to us, because Johns reminds us of what we know all too well: for the poor, the news is not good.
As Johns notes,
Bedbug infestations … are not random; they are reliably produced by social and economic conditions.
The poor often live in housing where bed bug infestations are neglected or poorly managed. This turns those buildings into bed bug reservoirs. If your building’s (or neighbors’ buildings) are allowed to become highly infested, it can be very difficult to avoid getting bed bugs, and very difficult to get rid of them once introduced.
Johns concludes optimistically that the epidemic in NYC may be waning, based on NYC government statistics reporting a decline in landlord bed bug violations in 2011, for the first time since 2004.
I think the jury’s out on that.
First, it still appears to be the case that almost all NYC tenants call their landlords and ask for treatment directly, rather than calling 311 and reporting a bed bug complaint (and without HPD complaints, there are no violations). That fewer people are calling HPD to complain may mean that now bed bugs are more commonly known, more landlords are responding to directly-made complaints — but this does not mean they are eliminating bed bug problems fully or swiftly.
Also, the NYC Housing and Preservation Department (HPD) statistics, assuming these were the source listed in the article as “New York City Department of Housing,” don’t cover NYCHA (public) housing. NYCHA residents don’t call HPD, they just tell their building managers about bed bugs in an apartment, and the city’s contracted firm treats them. The city statistics on bed bug violations also do not cover any co-ops or condos or privately-owned houses. It’s difficult to know how many of have been infested by bed bugs.
Even if the news is good and fewer tenants in privately-owned rentals are reporting bed bugs because fewer of them have bed bugs, it is likely, given what Johns has said about the links between poverty and bed bugs, that for many other residents of the city who live in buildings and neighborhoods where buildings are neglected and bed bugs are allowed to fester and multiply, things may not be getting any better, and may indeed be getting much worse.