Study shows bed bugs becoming insecticide resistant

New studies indicates bed bugs in the US have become resistant to the most widely used insecticide in the world, neonicotinoids.

"Don't let the bed bugs bite" is a phrase we've all heard before but new research shows the insects might not be so easy to avoid.

New research by entomologists in the US shows that bed bugs have developed resistance to neonicotinoids, one of the last known insecticides that kills the bug.

Professor Stephen Doggett is the only bed bug expert in Australia, he explains why he thinks the bed bug's immunity has risen so dramatically.

"There's a number of reasons why bed bugs may have developed a resistance to this group of insecticides called neonicotinoids and we suspect they have developed resistance to other insecticides. Now the term resistance is extremely complex; it covers a range of behavioural, cuticular, insomatic and what we call knockdown resistance. There's not form of resistance, there's multiple forms of resistance. When we get one form of resistance particularly the metabolic form that confers resistance to a whole range of insecticide classes."

Bed bugs were a common part of life in the 1940s and '50s, but the introduction of DDT insecticides initially restricted their populations.

By the 1960s the insects developed immunity to DDT, now banned because of its toxicity.

Next followed pyrethroids and finally scientists mixed a cocktail of neonicotinoids with pyrethroids to combat the bug, which until now did the job.

Fortunately bed bugs do not spread viruses or disease but they do leave a nasty bite and itch.

Student Elle Rudd describes her experience.

"It was less painful more itchy, it was that kind of burning itch that no matter how much you scratch it, it doesn't go away and it's just that kind of always humming itch that's under the skin and you just can't get to it - it drives you mad."

The US research, which began in 2012 in Cincinnati and Michigan, exposed bed bugs to four different insecticides.

It took 10,000 nanograms to kill a mutated, modern group of bed bugs which 30 years ago only needed 0.3 nanograms to kill.

The researchers say chemical-free methods should now be looked at.

In Australia, where significant bed bug pandemics have been witnessed, a code of best practice that uses a combination of heat and insecticide has already been developed.

Accommodation Association of Australia chief executive Richard Munro describes the method adopted here.

"Bed bugs are a worldwide phenomenon unfortunately and they travel predominantly in people's luggage so they can turn up anywhere and when and if they do turn up in a hotel rooms, immediate action is to quarantine the room and the luggage. It's very important to isolate everyone and the room then is heated, heat is installed into the room usually we use four by 2400 watt bar heaters and they're left in there for up to four days at 64 degrees Celsius and the idea of that is the bed bugs can't live in that environment."

This practice has meant cases in hotels are rare but total eradication of bed bugs remains elusive.

But Professor Doggett believes it could be possible.

"We need proper pest control, we need the appropriate use of non-chemical means and some of these inorganic compounds, like silicas, to be used widely and its very important for people to follow best practice in terms of control because nobody wants them in their bed. They are horrible, they are unpleasant, they irritate, they're just not nice."


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