Bug zappers create unhygienic germ spray
The electrocuting insect traps commonly used in fast food outlets are health hazards that create explosions of airborne bacteria and viruses spreading nearly two metres onto surrounding surfaces, according to new research.
The devices should not be used in food handling areas because the heat generated is not sufficient to destroy pathogens present on the insects' bodies, say the scientists who presented their work at the American Society of Microbiology's conference in Chicago yesterday.
"The bug zapper is probably not the method of choice for killing insects because it might actually aggravate the situation in terms of microbial spread," said Dr James Urban, associate professor of biology at Kansas State University.
What's more the zappers create millions of airborne insect particles, which can promote severe allergic reactions in some people.
Approximately one virus or bacteria out of every 4,000 on a fly's surface, and one in 10 million of those present in its digestive tract, are spread when the insect is killed.
Because flies can carry millions of pathogens, this can amount to a spray that is a significant health hazard, Dr Urban said. Surface contamination of flies was of particular concern because it was most likely to result from the flies moving about on "filth such as faeces," he said.
Dr Albert Broce, professor or entomology, said other studies had suggested portable versions of the machines, used to control mosquitoes in household backyards, did not live up to expectations.
More people were bitten by mosquitoes in the vicinity of the traps than away from them, because the lights attracted the blood-suckers, increasing their density. But once close to the trap, the mosquitoes tended to change course and direct their attention to nearby humans or animals.
In any case, the zapping machines killed only a small percentage of insects that were annoying or damaging to human health. They also indiscriminately killed beneficial insects that helped control other bugs, Dr Broce said.