Mosquitoes infected with a ‘miraculous’ bacteria have been shown to reduce dengue fever cases by 77%, in a groundbreaking new study.

Scientists released mosquitoes infected with ‘Wolbachia’ bacteria into the Indonesian city of Yogyakarta – but only in certain zones.

In the zones where the modified mosquitoes had been released, cases of dengue fell by 77% and hospitalisations dropped by 86%.

The results of the study, carried out by the World Mosquito Programme (WMP), were ‘better than we could have hoped for’, according to researcher Dr. Katie Anders.

Cases of dengue fever, a virus that can cause muscle and bone pain, and death, have risen rapidly in the past decades – there are an estimated 400 million cases a year.

The Wolbachia bacteria used in the trial were chosen because it hides in the same parts of a mosquito’s body that dengue virus hides in.

A bacteria that is benign to humans, the Wolbachia then competes for resources with the dengue virus, which makes it less likely for the mosquito to cause a dengue infection when it bites a human.

Researchers released five million mosquito eggs over a period of nine months in buckets of water in Yogyakarta city, in 12 separate zones.

The results of the study were so successful that the modified mosquitoes have now been released into the rest of the city, with the WMP now moving into surrounding areas to try and eliminate dengue in the region.

‘This trial result shows the significant impact the Wolbachia method can have in reducing dengue in urban populations,’ said professor Cameron Simmons, who helped lead the study.

‘This result demonstrates what an exciting breakthrough Wolbachia can be – a safe, durable and efficacious new product class for dengue control is just what the global community needs.’

The Wolbachia bacterium is also able to manipulate mosquito fertility to ensure it is passed down to future mosquito generations, hopefully eradicating dengue in years to come, unlike insecticides or sterilising male mosquitoes, which needs to be done regularly to suppress the insects.

Some disease modelling studies have shown that Wolbachia could be enough to completely suppress dengue fever, if successfully established in mosquito populations.

Scientists also hope that the same method could be applied to other diseases that inhabit similar parts of the mosquito’s body, like Zika, yellow fever and chikungunya.

‘This is the result we’ve been waiting for,’ said WMP program director Scott O’Neill.

‘We have evidence our Wolbachia method is safe, sustainable and dramatically reduces incidence of dengue.’

‘It gives us great confidence in the positive impact this method will have worldwide when provided to communities at risk of these mosquito-transmitted diseases.’

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