In a bid to combat dengue, scientists have successfully tested and prevented fresh outbreak of the mosquito-borne disease at a small town of Townsville in Australia. The test comes two years after the then head of India’s highest medical research organisation, Indian Council for Medical Research (ICMR), had stated that India was looking at a new policy to fight dengue. In an exclusive interview to The Indian Express on September 21, 2016, the then Director-General of ICMR Dr Soumya Swaminathan had said that a research work is underway on a bacterium named ‘Wolbachia’, which if introduced in mosquitoes, could prevent dengue viruses from growing and spreading. Swaminathan is currently posted as Deputy Director-General (Programmes) at the World Health Organisation.
What is a ‘Wolbachia’?
Wolbachia is a tiny micro-organism which is present in almost 60% of all species of insects and mosquitoes, except Aedes aegypti mosquito. The ‘Aedes aegypti mosquito’ is primarily responsible for spreading diseases like chikungunya, dengue and zika. Wolbachia is one of the world’s most common parasitic microbes and might be the most common reproductive parasite in the entire biosphere. The experiment was aimed at ascertaining whether injecting Wolbachia in Aedes Aegypti could reduce the transmission of disease.
What was the experiment?
A team of senior Australian researchers have managed to successfully protect around 1.87 lakh population of Queensland’s Townville from the mosquito-borne disease. The team was engaged in this job since last four years. During the test, mosquitoes which carry Wolbachia were let loose in more than 66 square kilometres so that they can naturally breed. Responding to an email of The Indian Express, Prof Scott O’Neill, who headed the World Mosquito Programme at Australia’s Monash University said, “When present in the mosquito, the viruses cannot replicate as well. So, small numbers of Wolbachia-carrying mosquitoes are released in target areas. They then breed with wild mosquitoes and over time the percentage of mosquitoes carrying Wolbachia grows until it remains high without the need for further releases.”
Prof Scott O’Neill further said, “Once Wolbachia has been established, the World Mosquito Program’s self-sustaining method offers a safe, effective and long-term solution to reduce the burden of dengue, Zika and chikungunya.” Apart from all these, research to combat mosquito-borne diseases are also underway in Rio de Janeiro (Brazil), Medellin (Colombia) and Yogyakarta (Indonesia).
India’s top medical research body is co-operating with Australia’s Monash University for Phase-1 laboratory studies so that it can take effective steps in controlling dengue and chikungunya. Addressing an event at National Vector Borne Disease Control Programme, ICMR officials have said that this approach is being tested in India. The authorities have imported mosquito eggs with Wolbachia and are being currently bred at Puducherry’s Vector Control Research Centre.
There were 15,000 dengue cases and 38 deaths in the country until July this year as compared to around 1.9 lakh dengue cases and 325 deaths across several states in the country in 2017.