22 Apr The spread of bed bugs – is there a historical precedent?

Europeans had been living in densely populated centres for many years and disease would ravage the populations frequently. As such Europeans that survived had been inoculated against these diseases and could therefore survive future outbreaks better. Native North Americans tended to live in smaller centers and were more isolated one from the other and the inoculation against these diseases was less pronounced.

When Europeans first colonized North America the health implications for the first contact Natives was dire. The Native populations were very susceptible to these new European diseases and often half or more than half of a tribal population would be wiped out with disease. The interesting thing for me was that these diseases tended to follow the established trade routes that Natives used. Tribes off the “beaten path” would not be impacted as quickly.

Bed bugs over the course of the last 50 years have been genetically mutating to avoid being killed by synthetic chemicals. About 20 years ago 2 of the 3 major classes of chemicals used for killing bed bugs was banned which left only the pyrethroid class of insecticide which has a similar mode of action to DDT.

DDT was banned years ago from developed countries but continued to be used with few controls in the developing world. Even when DDT was banned in North America there were certain genetic populations of bed bugs that were gaining resistance to DDT and the continued abuse of DDT in the developing world led to bugs that were highly resistant.

There is now speculation that, because DDT and modern pyrethroids have a similar mode of action, that DDT resistant bugs were able to quickly become resistant to pyrethroids. And these bugs would enter the developed world from the developing world via the established trade routes such as New York, Vancouver, and Toronto. And what we now see is that these major cities have worse bed bug issues than the smaller centers that are off the “beaten path.” For example, a Manitoba pesticide regulator official stated that, in terms of severity of problems between cities, Winnipeg might be a 2 out of 10 while Toronto is 8 out of 10. But it will simply be a matter of time before the severity levels even out.

It is interesting that the trade route theory seems to hold up here. So if you want fewer worries about bed bugs you should move to smaller centres (generally speaking of course).