Zamberi: Wolbachia-bearing mosquitoes need to be bred in a laboratory.
COMBATING dengue involves various strategies, one of which is the release of mosquitoes infected with Wolbachia bacteria to prevent the virus’ transmission.
In the Petaling district, Selangor government has implemented this strategy in 21 localities.
According to state public health and environment committee chairman Jamaliah Jamaluddin, as of the 19th epidemiological week (May 6 to 12) in 2024, eight out of the 10 localities involved achieved a reduction in dengue cases since 2019.
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Dengue cases in these eight areas decreased by 6% to 90%. However, two localities experienced an increase in dengue cases: Vista Lavender in Bandar Kinrara saw a 90% increase, and Desa Mentari Apartment in Petaling Jaya experienced a staggering 134% rise.
Jamaliah, in a statement to StarMetro, noted that the release of Wolbachia-infected mosquitoes had been effective in controlling dengue, but its success depended on the proportion of such mosquitoes in the locality, which should exceed 80%.
“To control dengue effectively, the frequency of Wolbachia-infected mosquitoes in a population needs to be high enough to significantly reduce the transmission of the virus.
“The threshold often mentioned is around 80% – meaning that at least 80% of the mosquito population should be infected with Wolbachia.”
She added that the Wolbachia mosquito initiative was still in the pilot phase in dengue hotspot areas in Selangor, so raising awareness on this measure was not yet a primary concern.
Dengue Prevention Advocacy Malaysia (DPAM) co-chairman Prof Dr Zamberi Sekawi said the best strategy to release Wolbachia-infected mosquitoes was to clear an area of any mosquito breeding grounds before conducting fogging.
“This ensures long-lasting effectiveness, as eliminating dengue-bearing mosquito breeding sites reduces their population prior to the introduction of Wolbachia-infected mosquitoes,” he said when contacted by StarMetro.
Wolbachia is one of several preventive strategies to combat dengue, but it is costly compared to other options available today.
Health Minister Datuk Seri Dr Dzulkefly Ahmad had on June 8 said that a single Wolbachia-infected mosquito cost 50sen.
Prof Zamberi pointed out that Wolbachia-infected mosquitoes needed to be bred in a laboratory, and thousands would be needed to ensure their effectiveness.
Universiti Putra Malaysia (UPM) Medical Microbiologist Department senior lecturer Dr Norashiqin Misni agreed that the cost to produce Wolbachia-infected mosquitoes was high, including research and pilot studies.
“However, once the wild mosquito population has been replaced with the Wolbachia strain, nature will take its course.
“They will breed on their own without needing to be released from the lab and without the need for fogging,” she said.
The use of Wolbachia-based control to reduce dengue cases has been researched in countries such as Australia, China, Singapore, Indonesia, Thailand, Vietnam, Brazil and Colombia.
This biological control method works by releasing mosquitoes infected with the Wolbachia bacteria, which inhibit the mosquito vector from transmitting the dengue virus.
Infected lab-grown mosquitoes that mate with wild mosquitoes do not produce viable offspring, thereby reducing the population of virus-transmitting mosquitoes over time.
In Malaysia, Wolbachia-infected mosquitoes have been released in 35 localities including Kuala Lumpur, Selangor and Penang.
According to Dr Dzulkefly, 19 of the localities involved recorded decreases in dengue cases ranging from 43% to 100% since the introduction of this project in 2019.
The project is still ongoing. — By LEW GUAN XI and MEGAT SYAHAR
