The fight against dengue fever – the most rapidly spreading mosquito-borne disease in the world – has stepped up a gear, findings published today in The New England Journal of Medicine reveal. In a large-scale clinical trial, there has been a 77 percent reduction in infections, thanks to a virus-fighting bacterium.
The bacterium in question is Wolbachia pipientis, the wMel strain to be exact. Wolbachia is found in many insects and is known to inhibit viral replication, making it more difficult for infected insects to spread disease. It is for these reasons it is a prime target for use in disease prevention. However, it has not (until now) naturally inhabited Aedes aegypti mosquitoes, the type that transmits the dengue virus.
The current study by the World Mosquito Programme, which took place in Yogyakarta city, Indonesia, where dengue is endemic, established a population of Wolbachia-infected mosquitoes over a period of nine months in 2017 and released them over half the city. Over the course of the trial, cases of dengue fever were reduced by 77 percent, while instances of hospitalization were reduced by 86 percent.
Following the trial’s success, mosquitoes have been released over the whole of the city and will next be released in surrounding areas, with the view to eradicating dengue across the region.
“This is a great success for the people of Yogyakarta. Indonesia has more than 7 million dengue cases every year. The trial success allows us to expand our work across the entire city of Yogyakarta and into neighbouring urban areas. We think there is a possible future where residents of Indonesian cities can live free of dengue,” said Professor Adi Utarini, co-principal Investigator of the trial, in a statement.
Unlike other insect-control methods, such as insecticides or sterilizing males, this method requires little upkeep and has the potential to be long-lasting – Wolbachia is able to manipulate its host, in this case, mosquitoes, altering their fertility to ensure they are inherited by the next generation.
The findings represent an “exciting breakthrough” in controlling dengue, which infects up to 400 million people a year according to the World Health Organization, says Co-Principal Investigator, Professor Cameron Simmons – “a safe, durable and efficacious new product class for dengue control is just what the global community needs.” As well as this, the use of Wolbachia-infected mosquitoes could be applied to treat other mosquito-borne diseases, such as Zika, yellow fever, and chikungunya.