As the Cayman Islands continues to use Oxitech labs to facilitate control of the Aedes Aegypt the United States is taking a slightly different approach according to a release to by Nature – The International Weekly Journal of Science.
The US Environmental Protection Agency (EPA) has approved the use of a common bacterium to kill wild mosquitoes that transmit viruses such as dengue, yellow fever and Zika, Nature’s news team has learned.
On 3 November, the agency told biotechnology start-up Mosquito Mate that it could release the bacterium Wolbachia pipientis into the environment as a tool against the Asian tiger mosquito (Aedes albopictus). Lab-reared mosquitoes will deliver the bacterium to wild mosquito populations.
The decision — which the EPA has not formally announced — allows the company, which is based in Lexington, Kentucky, to release the bacteria-infected mosquitoes in 20 US states and Washington DC.
“It’s a non-chemical way of dealing with mosquitoes, so from that perspective, you’d think it would have a lot of appeal,” says David O’Brochta, an entomologist at the University of Maryland in Rockville. “I’m glad to see it pushed forward, as I think it could be potentially really important.”
MosquitoMate will rear the Wolbachia-infected A. albopictusmosquitoes in its laboratories, and then sort males from females. Then the laboratory males, which don’t bite, will be released at treatment sites. When these males mate with wild females, which do not carry the same strain of Wolbachia, the resulting fertilized eggs don’t hatch because the paternal chromosomes do not form properly.
The company says that over time, as more of the Wolbachia-infected males are released and breed with the wild partners, the pest population of A. albopictusmosquitoes dwindles. Other insects, including other species of mosquitoes, are not harmed by the practice, says Stephen Dobson, an entomologist at the University of Kentucky and founder of MosquitoMate.
The EPA restricted the release of MosquitoMate’s product, called ZAP Males, to 20 states and Washington DC. The agency has previously said that those places “are similar in temperature and precipitation to areas where efficacy of the ZAP Males was tested” — Kentucky, New York and California. The EPA decision excludes much of the southeastern United States, which is home to dense populations of mosquitoes and a long mosquito season, because MosquitoMate did not conduct field trials there.
MosquitoMate plans to begin selling its mosquitoes locally, in Lexington, and will expand from there to nearby cities such as Louisville, Kentucky, and Cincinnati, Ohio. The company will work with home owners, golf courses, hotels and other customers to deploy its insects, according to Dobson. “Now the work starts,” he says.
The company will have to start small. Suppressing the mosquito population of an entire city would likely require the weekly production of millions of these mosquitoes. To reach that level, Dobson’s company must find a way to efficiently separate male mosquitoes from females. The company’s technicians now separate them both by hand and mechanically, Dobson says.
Another group that is also developing mosquitoes infected with Wolbachia to control wild populations has succeeded in producing large quantities of their insects. Researchers from Sun Yat-sen University in Guangzhou, China and Michigan State University in East Lansing say they are releasing five million Wolbachia-infected A. albopictus each week in Guangzhou, China.
The scientists use mechanical sorters to separate males from females based on their size difference in the pupae stage, with over 99% efficiency, says Zhiyong Xi, a medical entomologist and microbiologist at Michigan State University, who leads the project. They expose the remaining mosquitoes to X-ray radiation in a dose that sterilizes any remaining females but is too low to affect the males.
Zika continues to post a threat to many areas and CMR understands that Oxitech has not experienced the level of suppression locally that they had initially hoped for.