New types of mosquitoes have been developed in the country to eradicate and control dengue-chikungunya. In an attempt to curb vector-borne diseases, the Indian Council of Medical Research (ICMR) and the Vector Control Research Centre (VCRC) have created two mosquito colonies infected with a bacterium that aims to control the dengue strain.
An end to dengue, chikungunya and zika may be finally in sight, with scientists at a premier government research center working to infect domestic vectors with a bacteria that will—in around six months’ time—begin eliminating these viruses in them. The bacteria blocks the proliferation of harmful viruses but does not harm the mosquitoes themselves.
The Vector Control Research Center (VCRC) of the Indian Council of Medical Research (ICMR) has developed special female mosquitoes. These females, together with male mosquitoes, will produce larvae that will kill dengue-chikungunya. Because the virus of these diseases will not stay inside them. When viruses are not present, their bites will not infect humans.
In order to slow the spread of the viral disease, the ICMR-Vector Control Research Centre in Puducherry developed two colonies of Aedes aegypti that were infected with the wMel and wAlbB Wolbachia strains. These colonies have been labelled Ae. aegypti (Pud). Notably, the Aedes aegypti is a kind of mosquito that can spread dengue fever, chikungunya, Zika fever, Mayaro, yellow fever viruses, etc. This strategy was successfully adopted in Australia’s Queensland during a dengue outbreak.
Explaining the development, ICMR-VCRC Director, Dr. Ashwani Kumar was quoted as saying, “It is actually an endosymbiont. We call it endo means inside and biont means give and take relationship. What does it do in the sitting in every cell of mosquito, it actually makes it a home and then all Wolbachia here can effectively control the viruses, like dengue virus.”
Dr. Ashwani Kumar, a director, of VCRC, said, “Wolbachia is a bug which is found in 60% of insects naturally. But studies, including ours, have shown that in the case of the Aedes mosquito, a vector of dengue, chikungunya, and zika, this bug is in very low frequencies. So, what we have done is that we have acquired two strains of the Aedes aegypti eggs harboring Wolbachia— wMel and wAlb—from Monash University with the approval of the Indian government. From these eggs, we have raised colonies of these mosquitoes in our labs and allowed the females of the imported strains to mate with Aedes aegypti males of the Puducherry strain. In this manner, after six to seven generations, the mosquitoes will have genetic material closest to that of the Indian Aedes aegypti strain while the Wolbachia are inherited from the Australian strains.”
The ICMR has now asked VCRC to conduct more dengue challenge studies with these mosquitoes. So far, the research has been limited to the laboratories; once it is approved by the government, a pilot will be done by releasing the Wolbachia-carrying mosquitoes in the community. Between January and May alone, India reported 10,172 dengue cases with three deaths.
Independent risk assessment of this technology showed that there is minimal risk. The final call on whether these mosquitoes with Wolbachia should be released in the community will be taken by the Union government, Dr. Kumar said.