Infected vector unlikely to produce mutant animals, plants

KUALA LUMPUR: The release of Wolbachia-infected Aedes aegypti mosquitoes is unlikely to cause a biological backlash and produce “mutant” animals or plants.

Institute for Medical Research (IMR) director Datuk Dr Fadzilah Kamaludin said the release of the mosquitoes into the ecosystem was safe based on the institute’s risk assessment, which is largely based on Australia’s use of the infected vector to clip its dengue outbreaks.

“Australia first released Wolbachia-infected Aedes mosquitoes into its ecosystem nine years ago. Its findings revealed that the vectors are not transmitting the dengue virus.”

“The mosquitoes and bacteria strain were found to be present and stable in the locales they were released.

“And there was no additional bacteria or virus in them,” she said in an exclusive interview with the New Straits Times.

Fadzilah, however, denied that IMR relied solely on the Australian study, adding that the release of Wolbachia-infected mosquitoes into seven dengue hotspots locally had proven to be successful.

She said the Malaysian pilot project, which started in 2017, also found similar results to Australia’s, despite variables in climate and dwellings (housing).

“The infected mosquitoes are still found in the locales carrying the pathogen, while the ability to transmit dengue has been blocked.”

She said the sister species, Aedes albopictus, was a natural carrier of Wolbachia in Malaysia and Singapore, and had “bitten humans for decades without spreading dengue to them”.

No reports and evidence of these mosquitoes carrying any other viruses or other vectorborne pathogens were observed in Cairns, Australia, where the release programme started eight years ago, she said.

She said IMR would study the mosquitoes in their environment once every two months.

“When we are satisfied with the results, we will check on them once every six months.”

In October 2014, four million Aedes aegypti mosquitoes were released over 66 sq km in Townsville, a coastal city in northeastern Queensland, Australia.

Townsville, which faced periodic dengue outbreaks since 2001, recorded only four locally acquired dengue cases in the 44 months after the release began.

Breakdengue, a non-profit organisation that aims to connect different initiatives around the world in addressing dengue, said other studies had raised concerns that Wolbachia could increase vector-borne pathogens in insect populations.

“Research published in 2014 found that Wolbachia boosts the West Nile Virus infection in the Culex tarsalis mosquito.

“The main message from the study was that we need to keep an eye out to ensure Wolbachia does not increase a mosquito population’s ability to transmit one virus as we employ it to lessen the population’s ability to transmit another,” it said.