Bacteria to bite back at mosquitoes

PETALING JAYA: A research programme is underway to use a type of bacteria that fights mosquito-borne viruses, including the dengue virus.

Health director-general Datuk Dr Noor Hisham Abdullah said the pilot project, which costs RM3.836mil, will be carried out by the Institute of Medical Research (IMR). The programme will be funded by the Wellcome Trust Fund.

IMR is collaborating with Lancaster University, Britain, and the Melbourne University, Aus­tra­lia, to work on a project to infect the aedes aegypti mosquito with Wolbachia bacteria, he said.

“When they are released into the wild, they will spread the Wolbachia into the aedes aegypti mosquito.

“The Wolbachia will block the dengue virus from replicating within the mosquito,” he said in an interview.

According to www.eliminatedengue.com by Melbourne Uni­versity scientific collaborators, Wolbachia are bacteria that live inside insect cells and are naturally occurring in up to 60% of all insect species, including butterflies, dragonflies, moths and many mosquito species, but not aedes aegypti.

Wolbachia reduces the ability of insects to become infected with viruses.

“Since there is no cure or specific treatment for dengue, the main strategy is to attack aedes aegypti, the mosquito that transmits the virus,” he added.

He said the effect of Wolbachia on disease transmission will be evaluated continuously after release.

The project will end in 2020, but this may be subject to changes, he added.

Dr Noor Hisham also said that common insecticides, such as organophosphate (temephos) and pyrethroids (permethrin) have lost much of their effectiveness as the mosquitoes were found to have developed resistance while bed nets are not effective since the aedes aegypti are daytime biters.

Asked on the success rate of the method, he said studies have shown that Wolbachia had reduced the ability of mosquitoes to transmit chikungunya, dengue and Zika viruses.

“A dengue-mitigation project in 2014 in Brazil showed that it was able to reduce the spread of Zika and chikungunya viruses,” he added.