Researchers say Wolbachia bacteria method cuts dengue by 77% in trial

  • News Desk, bdnews24.com
    Published: 2021-06-10 20:38:02 BdST

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Scientists have successfully cut dengue fever cases by 77 percent by infecting Aedes aegypti mosquitos with “miraculous” bacteria to reduce their ability to spread the disease, the BBC reports.

The trial was carried out in Yogyakarta city, Indonesia, and is being expanded in the hope of eradicating the virus, the report added.

The World Mosquito Programme team is optimistic it could be a solution to a virus that has gone around the world.

One of the researchers, Dr Katie Anders, describes them as "naturally miraculous".

The trial used mosquitos infected with Wolbachia bacteria, which are natural bacteria present in up to 60 percent of insect species, including some mosquitos.

However, it is not usually found in Aedes aegypti mosquito, which is responsible for transmitting human viruses such as dengue, chikungunya and Zika.

When introduced into the Aedes aegypti mosquito, Wolbachia can help reduce the transmission of these viruses to people, the World Mosquito Program’s research has shown.

When a female mosquito mates with a male, with at least one of them bearing Wolbachia, they will produce Wolbachia-infected mosquitos.

Mosquitos with Wolbachia have a reduced ability to transmit viruses to people, decreasing the risk of fatal diseases such as dengue.

In the trial, Aedes aegypti mosquitos were injected with the bacteria, which camps out in the parts of its body that the dengue virus needs to get into.

The bacteria compete for resources and make it much harder for the dengue virus to replicate, so the mosquito is less likely to cause an infection when it bites again.

The trial used five million mosquito eggs infected with Wolbachia. Eggs were placed in buckets of water in the city every two weeks and the process of building up an infected population of mosquitos took nine months.

Yogyakarta was split into 24 zones and the mosquitos were released only in half of them.

The results, published in the New England Journal of Medicine, showed a 77% reduction in cases and an 86% reduction in people needing hospital care when the insects were released.

"It's very exciting, it's better than we could have hoped for to be honest," Dr Anders told the BBC.

The technique has been so successful that mosquitos have been released across the whole city and the project is moving to surrounding areas with the aim of eradicating dengue in the region.

Dr Anders, who is also the director of impact assessment at the World Mosquito Programme, said: "This result is groundbreaking.

"We think it can have an even greater impact when it is deployed at scale in large cities around the world, where dengue is a huge public health problem."

Wolbachia are also spectacularly manipulative and can alter the fertility of their hosts to ensure they are passed onto the next generation of mosquitos.

It means once Wolbachia has been established, it should stick around for a long time and continue to protect against dengue infection.

David Hamer, a professor of global health and medicine at Boston University, said the method had "exciting potential" for Zika, yellow fever and chikungunya.