Our interest was recently piqued by a New York Times article that talked about the problem of bed bugs in libraries across the country, and specifically mentioned the University of Washington Libraries, which are in Seattle.
Seattle is the home town of ZappBug, and the UW is the alma mater of two of our co-founders. But more than the geographic location, we were particularly interested to learn about UW Libraries’ bed bug treatment method.
Unlike most libraries which use heat to treat infested books, the University of Washington Libraries use freezing to kill bed bugs in books, because they feel that heat can accelerate the aging of books. (Our own experiments with heating up books show that heat can sometimes slightly curl the pages of books but we haven’t noticed any aging.)
We agree that freezing can kill bed bugs, but we feel that you have to be very careful when using this method, because the scientific evidence is unclear how long they must be frozen and how far below the freezing point the temperature must be. If bed bugs aren’t frozen at temperatures cold enough or for long enough, then the bugs and/or eggs might survive.
The UW Libraries have developed a protocol in which they seal potentially infested books in plastic bags and freeze them at temperatures below 18 degrees Fahrenheit for one week. Then the books are allowed to unthaw and be a room temperature for 6 days. And then are re-frozen for another week in case any surviving eggs have hatched.
There are no scientific studies showing the efficacy of this method. But we feel that, in all likelihood, it is effective because of the long lengths of time involved at temperatures well below the freezing point and because of the extra step of unthawing and refreezing to kill any eggs that might survive and hatch.
The main drawback that we see to the UW Libraries’ protocol is that it takes nearly 3 weeks to treat books.
Most libraries have elected to go the route of heat treatment to kill bed bugs in books, because there are scientific studies to back up the efficacy of heat in killing bed bugs in all life stages, including eggs.
And for many libraries it’s a much more practical solution, because the time frame is much shorter. With a bed bug oven such as ZappBug or Packtite, the treatment time for books is usually about 5 hours.
Here’s a video of ZappBug killing live bed bugs in a book: http://youtu.be/pZfaMOhlBMA
Posted by Andrew Havlis