Subjected herself to bedbug bites: Dr Regine Gries.
When someone comes to write the biography of Canadian scientist Dr Regine Gries, it will probably be titled “Love Story With Bedbugs”.
For the past five years, at the behest of her biologist husband Gerhard, Gries has every week subjected herself to 1000 bedbug bites in a quest to develop an effective control for the little blighters. (Gries’ immune system is unusually resistant to the irritating, pustule-producing bites so she develops only a mild rash.) In January the intrepid pair, from Simon Fraser University in British Columbia, announced the invention of a handy pheromone-laden trap.
The device, expected to go into production soon, will be greeted with particular enthusiasm in Australia, where reports of bedbug infestation over the past few years have gone through the roof. Or, more pertinently, the mattress.
Adult lice and a nit.
The bug issue is indicative of a wider, and sobering, realisation. Scientific achievements in recent years have been staggering – discovering the Higgs Boson, creating the HPV vaccine, and landing a spacecraft on a comet all spring to mind – but controlling household pests remains a dodgy business.
Indeed, at least three of the insects that Australians daily battle in their lounges and boudoirs – bedbugs, mosquitoes and head lice – have been noted as domestically loathsome since the time of the Pharoahs. The good news, however, is that when it comes to mozzies and lice, Australian scientists are producing some world-leading strategies in the battles to control them.
With mosquitoes, the major problem is not their incessant whining and itchy kisses but their microbe-filled gob that infects billions worldwide with diseases such as malaria and dengue fever.
A young girl being treated for head lice. Photo: iStock
Around 2.5 billion people share their homes and gardens with dengue-infested mosquitoes. Up to 100 million cases of the disease are reported annually. In Australia, dozens of people, mainly in far north Queensland, contract it each year, with up to 500 more getting sick while travelling overseas.
Although it is rarely fatal, dengue causes chronic flu-like symptoms that are often debilitating, especially in children. Global warming models suggest dengue-carrying mozzies will enjoy an increased range over the coming years.
Control methods generally involve the deployment of vast clouds of insecticide. It’s a technique that often results in the loss of other insect species – many of them useful – and produces only temporary dips in the mozzie population.
Head lice.
An Australian-led research project called Eliminate Dengue has come up with a novel, natural and – at least on trial results – extremely effective way of combatting the disease. The research suggests that in a few short years dengue fever might be extinct worldwide – without a single squirt of Mortein.
The Eliminate Dengue project makes use of a species of bacteria, called Wolbachia, that lives in about 60 per cent of insects, including some non-dengue-carrying species of mosquito. The project began when researchers discovered that introducing the bacteria into the dengue-carrying mosquito effectively inoculated the insect, rendering it – and hence its human dinner – dengue-free.
Small-scale field tests began in Queensland in 2012. Dr Peter Ryan, Eliminate Dengue’s program manager, based at Monash University, said the latest chapter in the story began a couple of months ago.
“Late last year we started our first medium-to-large scale trial in Townsville, a city of 50,000 people,” he told Fairfax Media. “If it works there, it will be evidence that the technology we use can be scaled up to cover large areas. It’s very important that the science works in real world settings.”
The results of initial trials conducted around Cairns, said Ryan, were promising. “We have some trials now that have been going on for close to three years,” he said. “We’re seeing that Wolbachia has remained in the mosquito populations, and we’re seeing no evidence of dengue transmission.
“However, in Australia dengue tends to be sporadic – it comes and goes in the mosquito populations, and some years are worse than others. Our next trials need to be in areas where dengue has year-round transmission, such as Vietnam.”
Eliminate Dengue’s solution to a major pest problem is not only elegant and long-lasting, it also avoids one of the major problems associated with mass-pesticide schemes. As bedbug researchers discovered, using too much poison creates a problem that, much like the bedbug itself, comes back to bite you on the bum.
After World War II, most developed nations moved to control bedbug infestation by using insecticides such as DDT. The bugs were almost entirely eliminated. “Almost”, however, is the key term.
By the start of the twenty-first century numbers were rising steeply. Westmead Children’s Hospital in Sydney reported a 400 per cent rise in bedbug cases between 2000 and 2004. Worse, the bugs had descended from hardy DDT-survivors. In 2014, Westmead researchers announced that the little buggers were pesticide resistant.
So Gries’ hard-won Canadian trap looms as the best hope for controlling that species. For another common household pest – one about to enjoy a population boom now that kids have gone back to school – a Melbourne University team might just have come up with a new solution.
The fine-toothed comb traditionally used to control head lice hasn’t changed much since it was first used in ancient Egypt. Starting in 2001, however, scientists at the university’s Centre for Animal Biotechnology started working on a lotion that would kill lice and eggs without the need for hours of tiresome brushing.
Clinical trials have now been completed and the lotion, dubbed Xeglyze, will be submitted for approval with the US Food and Drug Administration later this year. Once the paperwork is done, here and there, the project’s lead researcher, Professor Vern Bowles, will be set to receive the thanks of grateful parents around the globe.
It’s taken millennia but, bit by bit, the battle against bugs is being won. Now, if only something could be done about a few other common pests, such as fleas, silverfish and door-to-door sales-people.