- Bedbugs becoming more resistant to sprays
- Resurgence of the bugs "an urgent situation"
- Infestations increasing in Australia, the US
Blood-sucking bedbugs are one thousand times more resistant to common pesticides compared to a decade ago and are invading cities around the world, scientists have warned.
Researchers from Ohio, US, made the surprising discovery when building a genetic map of the pests, which are about the size of an apple seed, and have warned of future infestations.
"The resurgence of bed bugs poses an urgent situation as infestations are rampant globally, nationally, and locally," the researchers wrote in the Public Library of Science journal PLoS ONE.
Resistance to chemicals designed to kill the bugs can become a permanent part of their genetic inheritance. The bugs are now also less prone to stress from heat, cold and dehydration.
The study also identified a spike in the number of bed bug infestations around the world, including in Australia.
"During the past decade or so, the resurgence of (bedbugs) has been recorded across the globe including North America, Europe, Australia, and Eastern Asia with an estimated 100 per cent to 500 per cent annual increase in bed bug populations," the researchers wrote.
The rust-coloured bugs have been a particular pain to some US cities, with sightings in New York and the United States surging in recent years.
Travellers have been warned to be more vigilant and to check rooms before checking-in.
"Everyone has got to get used to the idea that they have got to check for them periodically," New York City environmental health commissioner, Daniel Kass, said.
"People who travel should look at the rooms they're staying in. They should check their clothing. There are good preventive measures."
Experts recommend looking for bugs with a bright flashlight, and using a hot hair dryer to flush them out of hiding places and cracks.
People who have bedbugs often never see them. The most obvious signs are bites, blood on bedsheets and their waste, which looks like black pepper. They are known for being extremely difficult to eradicate, and can go a year without feeding.
Bedbugs were nearly dormant for decades, and the recent comeback has experts scratching their heads.