Mosquitoes infected with bacteria can limit the spread of dengue, studies in five countries have shown, and now this biotechnology is being considered for dengue control in india.
On Tuesday, the Indian Council of Medical Research signed a memorandum of understanding with Monash University in Australia, one of the countries in which studies have been conducted and where the vector control technology has been developed. The first phase of the trial will examine the impact of Wolbachia – a genus of bacteria that normally infects arthropod animals like insects and butterflies – on dengue and chikungunya viruses in India. The trial will be conducted at the Vector Control Research Centre in Puducherry.
A team of Australian scientists have successfully transferred a strain of Wolbachia bacteria into Aedes mosquitoes that spread dengue, chikungunya and Japanese encephalitis. The naturally-occurring Wolbachia bacteria, which is present in 60% of insect populations, limits the replication of the disease-producing virus such as dengue and chikungunya. The technology is being tried in Brazil, Columbia, Indonesia and Vietnam.
In Australia’s cities like Townsville and Cairns, and some sites in Indonesia where the technology was used, there has been no local transmission of dengue since the introduction of the bacteria into the mosquito population, said Professor Scott O’Neill from Monash University. The bacteria could also work to limit the growth of the West Nile and Zika viruses.
“The key point with the use of Wolbachia is that the bacteria gets passed down from one generation to another,” said O’Neill. “As a public health intervention, it provides ongoing protection and does not have to be reapplied.”
The bacteria is also safe for the environment and human beings, said Dr Soumya Swaminathan, director general of the Indian Council of Medical Research. The bacteria only lives in cells of the insects and does not infect humans.
“We have to study how practical it is to breed the mosquitoes and release them,” said Swaminathan. “We also have to understand the cost-effectiveness of vector control.”
So far, India has been relying on insecticides for vector control. The government could consider using this technology with the existing tools of vector control, said Dr P Jambulingam from the Puducherry institute.
The technology has also been tried on the anopheles mosquito, which transmits malaria. “Initial results show that the bacteria impedes malaria parasite,” said O’Neill.