Wolbachia bacteria to curb dengue cases - Health DG

The usage of 'Wolbachia' microorganism injected into the Aedes aegypti mosquito eggs is seen as a method to prevent the spread of dengue virus among human.

This is because the eggs, which had been injected, do not carry dengue virus and thus prevent from dengue being spread.

Health Director-general Datuk Dr Noor Hisham Abdullah said the country's use of Wolbachia was introduced in January by the Institute for Medical Research (IMR) in collaboration with Lancaster University, United Kingdom.

He said, IMR had received the eggs of Aedes mosquito containing Wolbachia bacteria and it is undergoing the breeding process.

"IMR are using the replacement method of male and female Aedes aegypti mosquito containing Wolbchia to be released into the field.

"After reproduction, most of the Aedes aegypti which contain Wolbachia will no longer produce dengue virus," he said adding that IMR was currently conducting population surveillance of the mosquito in the field.

This is important to plan the release rate or total numbers of male and female mosquitoes containing the microorganism to be discharged into areas identified to have a high number of dengue cases.

The usage of Wolbachia in mosquitoes in the selected areas is a pilot project that will be reviewed after three years from January next year.

Dr Noor Hisham said there was another method of reducing the mosquito population, namely by releasing the male Aedes mosquito containing Wolbachia in large numbers.

The male mosquito will mate with the female mosquito but the eggs which those mosquitos produce will not hatch thus reducing its population.

Wolbachia is a microorganism that lives naturally in the reproductive organs of insects and exists in about 60 per cent of insects except Aedes aegypti mosquitoes.

Dr Noor Hisham said due to the fact that there is no Wolbachia in Aedes mosquitoes like most other insects, the injection should be carried out in the laboratory before it is released into the field.

He said the Wolbachia method has been used in several countries including Australia and China.

In Australia, a study conducted by the Commonwealth Scientific and Industrial Research Organisation in 2011 found that the areas which had been released with Wolbachia mosquitoes caused no environmental pollution, animals and insect that might be infected by Aedes mosquito also showed no changes or disease.

In China, studies showed no Aedes eggs hatched after the Wolbachia mosquitoes had been released.

"Indonesia, Thailand and Vietnam are also conducting a study of the microorganisms, while Singapore and the United States plan to launch this method to tackle the spread of Zika virus.

"The results of laboratory studies indicate this method is suitable to inhibit the reproduction of Zika virus and Chikungunya in the Aedes mosquito," he added. -- BERNAMA