Bedbugs were thought to be a thing of the past thanks to the use of dichlorodiphenyltrichloroethane, or DDT, which was developed during the 1940s.<\/p>\n
But the bugs made a resurgence during the 1990s and early 2000s, and the longtime theory was that international travelers, who were able to fly more due to less expensive airfares,\u00a0were responsible for the bugs hitching a ride out of Europe and to the United States.<\/p>\n
Turns out, that theory is not supported by research findings.<\/p>\n
\u201cWhat we found was that there was no real evidence that there was a lot of genetic exchange occurring between Europe and the U.S. and Canada, or vice versa,\u201d Warren Booth, professor of urban entomology at Virginia Tech, said.<\/p>\n
Using whole genome sequencing and insecticide resistance-associated genes, \u201cwe found out there was a clear pattern of differentiation that Europe was on its own, the U.S. was very much on its own, and Canada fell somewhere in between, more associated with Europe than with the U.S., which is kind of really interesting considering we share a border,\u201d Booth said.\u00a0<\/p>\n
Not only does the research debunk the idea that the 1990s bedbug resurgence was due to international travel, \u201cwhat the data actually did tell us was that it looks like populations never went away in the U.S.,\u201d he said.<\/p>\n
\u201cThey likely remained probably, unfortunately, in low-income housing or in rural areas where pest control wasn\u2019t common and wasn\u2019t easily\u00a0obtained,\u201d he said. \u201cAnd as a result, over time they simply resurged \u2026 probably because they have evolved resistance to most of the major insecticide active ingredients that are out there,\u201d he added.\u00a0<\/p>\n
The U.S. banned the use of DDT in the early 1970s, but there has been a constant development of chemicals to keep pests such as bedbugs under control.<\/p>\n
\u201cIf we look at when active ingredients were introduced following DDT, we had a time series where you had new active ingredients coming out. And within four to five years, we see evidence of resistance occurring in most insect species that have been subjected to them, and bedbugs are no different. We find that they\u2019re resistant to the majority of the active ingredients present,\u201d Booth said.<\/p>\n
Long story short, the right set of circumstances aligned in the wrong ways allowed the bugs an avenue of return.<\/p>\n
\u201cI think the reason we saw them suddenly appearing in the early 2000s was it was just the right time,\u201d Booth said. \u201cThey were resistant to all of the major active ingredients, and there was nothing kind of reducing populations.\u201d<\/p>\n
Bedbugs in the U.S. are a genetically diverse bunch, but when it comes to at-home infestations, they lack diversity, according to Booth. That\u2019s because bedbug infestations \u201ccan start from a single pair of individuals or a single female that\u2019s pregnant, and they will interbreed and inbreed for generations and generations.\u201d<\/p>\n
Booth said his lab has colonies that have been in culture and inbreeding for over 50 years where only one female needs to be pregnant and then it will \u201ccause a nightmare in your home.\u201d<\/p>\n
\u201cIt\u2019s a very unusual system, but many invasive insects can use this and overcome what would normally be detrimental for most species,\u201d he said. \u201cThey seem to be able to override that and form very large populations through inbreeding.\u201d<\/p>\n
And it doesn\u2019t take long for them to reproduce and wreak havoc.<\/p>\n
\u201cFrom one, you can end up within a month with several hundred, and when they all start breeding, within six months, you could end up with over 30,000,\u201d Booth said.<\/p>\n
Infestations can spread really rapidly, he points out. <\/p>\n
\u201cWe studied a population in North Carolina in an assisted living facility that we traced back to probably one introduced female that was pregnant, and that spread through nine stories and 81 apartments within two years. So, they\u2019re a pretty horrifying species if you, unfortunately, get to interact with them,\u201d Booth said. <\/p>\n
If you find bedbugs in your home, it\u2019s best to let pest control experts take care of them.<\/p>\n
\u201cWith the common insecticides that are pyrethroid-based, for example, we\u2019ve shown that they\u2019re about 16,000-fold resistant to that, so it\u2019s going to do nothing for them. They can do the backstroke in there, and they\u2019re going to come out happy, so it\u2019s best to go with a reputable firm that\u2019s going to be effective,\u201d he recommends.<\/p>\n