Bedbugs pose an itchy nuisance by feeding on human blood, but there's little chance that the insects will transmit disease, say researchers who reviewed the evidence.
Bedbugs (Cimex lectularius) are spreading in hotels, homes, subways and movie theatres despite pest control efforts.
Earlier studies suggested that bedbugs might transmit blood-borne diseases like the plague, yellow fever or HIV, but a review of 53 articles in Wednesday's issue of JAMA, the Journal of the American Medical Association, dispels the idea.
"Bed bugs are likely to be more problematic in the future due to travel, immigration and insecticide resistance," Jerome Goddard, an entomologist at Mississippi State University and Dr. Richard deShazo of the University of Mississippi Medical Center in Jackson concluded.
"Development of effective repellents and public education about bed bugs are also important goals."
Public health experts in Toronto reported a 100 per cent increase in telephone complaints about bedbugs during a six-month period in 2002. More infestations have been reported in homes, apartments, hotel rooms, hospitals and dormitories in the U.S. since 1980, the researchers said.
There have also been lawsuits against hotels with infestations, but five-star hotels are just as susceptible as cheaper places since travellers bring along the pests in their luggage.
Check hiding spots
The review showed that most bedbug bites don't cause a reaction with only a barely visible mark where the insect had its feast.
The most common reactions that prompt people to seek medical attention are lesions that usually itch, and usually resolve within a week if not made worse by scratching, the researchers said. Allergic reactions are rarer.
The bugs can live up a year without feeding and have developed resistance to some insecticides. Bait traps don't work because the pests feed only on blood.
The insects' favourite hiding spots include seams in mattresses, crevices in box springs, the backsides of headboards and spaces under baseboards or loose wallpaper, the study's authors said.
People can look for the five-millimetre-long bugs or their black feces marks. Pest control experts can help, and mattresses and box springs can be covered with encasements similar to those used for dust mite allergies to prevent any remaining bugs from feeding.