Wolbachia-infected mosquitoes project may turn tide in battle against dengue

A worker carries out fogging to eliminate mosquito breeding grounds, but with the introduction of Wombachia-infected mosquito it will get rid of the Aedes mosquito. ― Malay Mail pic
A worker carries out fogging to eliminate mosquito breeding grounds, but with the introduction of Wombachia-infected mosquito it will get rid of the Aedes mosquito. ― Malay Mail pic

KUALA LUMPUR, Feb 9 — The Institute for Medical Research (IMR) believes the release of Wolbachia-infected mosquitoes could finally help the country win the battle against Aedes mosquitoes and dengue.

Its director Datuk Dr Fadzilah Kamaluddin said the programme was recommended by the World Health Organisation and it had proved successful in a few countries.

“There have been no more Aedes mosquitoes in Yorkeys Knob and  Gordonvale, Australia after the first five weeks of the Wolbachia-infected mosquitoes being released,” she told Malay Mail yesterday.

The Health Ministry will be releasing the Wolbachia-infected mosquitoes in  Section 7, Shah Alam and AU2 Keramat end of March.

Section 7, Shah Alam had among the highest number Aedes cases, 4,005 between 2012 and 2016, while AU2 Keramat had 198 cases.

Dr Fazillah said a collaborative study was done in June last year between the ministry, IMR, Lancaster University, Britain and University of Melbourne, Australia.

The study used the “Replacement Method” to identify how Wolbachia-infected mosquitoes could assist in the reduction of dengue mosquitoes in hotspot areas.

“The presence of Wolbachia-infected mosquitoes in the open space will allow them to mate with Aedes mosquitoes and stop their reproduction,” she said.

“Aedes mosquitoes will eventually be incapable of transmitting dengue to humans. In time, elimination of the disease will become a reality.”

She pointed out that the infected mosquitoes were not genetically-modified insects as the Wolbachia bacteria could be found in almost 60-70 per cent of insects.

“Wolbachia infections in a new host species are created by injecting the eggs using a technique called microinjection,” she said, adding Wolbachia could only live inside host cells and were not able to transmit between insects.

The Wolbachia-infected mosquitoes project will be evaluated in December 2020, before the Health Ministry decides whether to extend the programme to other states.

The use of mosquitoes in battling dengue is not new in the country. Three years ago, toxorhynchites (toxo) mosquitoes were released in Subang Jaya.

Subang Jaya Municipal Council president Datuk Nor Hisham Ahmad Dahlan said, however, the programme had met with limited success due to environmental conditions.

“The impact was not what we expected it to be as the toxo mosquitoes required the area to be filled with trees and bushes for the programme to be successful,” he said.

He added the programme was still ongoing and would not stop as the council and health authorities were still monitoring its development.

“We will continue with this project as long as possible and have no intention of stopping it.”

The toxo mosquitoes, also known as “elephant mosquitoes”, eat other mosquito larvae, including Aedes larvae. They will also eat their own larvae if there is no other mosquito larvae available.

Adult toxo mosquitoes feed on plant nectar, and not blood, and are harmless to humans.

The mosquitoes are not genetically modified and they originate from tropical forests.

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