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Bloodthirsty Bedbugs Stage Comeback in U.S., Europe

James Owen
for National Geographic News
May 13, 2004
 
"Sleep tight, don't let the bedbugs bite." This old saying may be becoming newly relevant. Bedbugs, which feast on human blood at night, are biting back in developed countries around the world.

The current invasion of North America, Australia, and Western Europe is highlighted in a new study published by the Institute of Biology, London. But it's still unclear why the parasites are returning to cities where they were exterminated some 50 years ago.


"The trend is very worrying," said the report's author, Clive Boase. Boase runs the Pest Management Consultancy in Haverhill, England. "Since the mid-1990s, numbers of reported infestations have almost doubled annually."

In parts of London bedbug infestations have risen tenfold since 1996, Boase says. In the U.S. the National Pest Management Association reports a 500 percent increase in bedbug numbers in the last few years.

Similarly, in Australia, there were as much as 700 percent more calls to pest-control companies in the four-year period ending in 2004, compared with the previous four-year period, according to the Institute of Clinical Pathology and Medical Research (ICPMR) in New South Wales.

The bug's dramatic comeback is perplexing, Boase says. The rebound comes even as other creepy crawlies, such as cockroaches and ants, are in retreat from people's homes. Boase says possible factors fueling bedbugs' global spread include growth in international travel, increased resistance to certain insecticides, and the introduction of new pest-control methods that leave bedbugs unharmed. Yet, he says, the precise cause or causes of the problem are yet to be determined.

In the 1930s the U.K. Ministry of Health stated, "In many areas all the houses are to a greater or lesser degree infested with bedbugs." But infestations quickly receded once synthetic pesticides such as DDT were introduced following World War II. By the 1980s bedbugs were almost nonexistent in Britain, the U.S., and many other developed countries.

No bigger than an apple seed, the bedbug is descended from plant-feeding insects that evolved skin-piercing mouthparts for sucking up blood. They are thought to have first gotten a taste for human blood when cave-dwelling humans lived beneath bug-infested bat roosts

Hiding Places

Bedbugs are notoriously difficult to locate. They hide in mattresses and furniture, under floorboards, and even inside electrical equipment, emerging to feed only when it's dark. Adults can survive up to a year without blood, allowing infestations to persist through periods when properties are vacant.

Side effects of bedbug bites include itchy body swellings. Boase says that in rare cases—usually involving people living in poverty—severe infestations may lead to severe blood loss, due to the volume of feeding by hundreds or even thousands of bedbugs.

While studies have shown that HIV can survive on bedbugs' mouthparts for up to an hour, the insects are not known to be vectors for disease.

In Australia the majority of reported infestations have been in budget accommodations and backpacker hostels. Bedbugs are also being found in homes, hotels, and even in cruise ships.

In the U.S. the parasites are now widespread along both the East and West Coasts and everywhere in between, says Cindy Mannes. Mannes is the director of public affairs for the National Pest Management Association, based in Dunn Loring, Virginia.

"The last 12 months have been particularly active," she said. "They are showing up like never before in hotels, hospitals, college dormitories, and multifamily housing units as well as single-family homes."

New York City has been hit particularly hard, says Andy Linares, president of Bug Off Pest Control Center, the city's biggest supplier of insect poison. He said the company now receives dozens of calls each week.

"It's a generalized problem found throughout the city, without regard to geography [or] economic or social status," Linares said. "What they have a taste for is a blood meal and harborage in dark cracks and crevices close to where humans rest and sleep."

Travelers and immigrants have been widely blamed for reintroducing the parasites. "With nowhere in the world now more than a few days away, it is easy to see how infestations of these insects may suddenly appear almost anywhere," said the Pest Management Consultancy's Boase.

Tropical Bedbugs

In many less developed countries infestation levels are similar to those seen in 19th-century Europe. In some Indian and African cities, at least 65 percent of homes are infested by tropical bedbugs (Cimex hemipterus), studies indicate.

But Boase isn't convinced that international travel is behind the bedbug pandemic. If it were, he says he would expect tropical bedbugs to be turning up alongside the better known temperate bedbugs (Cimex lectularius).

Boase has carried out surveys of areas of southern England that have a high percentage of foreign nationals. Those surveys haven't detected a single tropical bed bug.

This isn't to say that temperate bedbugs aren't hitchhiking to Britain from elsewhere. But Boase believes the origins of the problem lie closer to home.

For instance, some scientists suspect bedbugs may have developed multiple resistances to pesticides. A recent study in East Africa found a link between the use of mosquito nets treated with insecticides and the development of insecticide resistance in bedbugs.

Boase also points to the fact that pest treatments have become more species specific. Previously, broad-spectrum insecticides used on cockroaches and other pests also wiped out bedbugs.

In Australia tropical bedbugs were reported for the first time last year. And air travel does appear to be a factor, according to Stephen Doggett, from the Department of Medical Entomology at the ICPMR.

Doggett says that 74 percent of all bedbug interceptions ever reported by the Australian Quarantine and Inspection Service have occurred since 1999. The bugs were found mainly in personal baggage arriving from Asian or Pacific countries.

Doggett suggests that the stigma attached to the parasites is influencing hotels and other accommodations to ignore infestations or treat them without professional help. Lack of professional treatment comes with great risks, he warns, notably the possibility of litigation.

"In a landmark case a motel chain in the United States was successfully sued for [U.S.] $382,000 after guests were bitten by bedbugs [Matthias v. Accor, 2003]," he said.

It's only a matter of time, Australia-based Doggett adds, before litigation over bedbugs occurs in his own country—just one more reason these pesky parasites are causing so many sleepless nights.
 

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