Inserting mosquitoes with Wolbachia bacteria reduces dengue infection
Dengue and its seriousness came into light in the late 90s and since then it’s been a slow life-sucking epidemic in many parts of the world. Every year, 400 million dengue infections are reported, and if not controlled in time, it has proven an explosive outbreak that can often overwhelm hospitals. Normally, after the onset of dengue, the patient experiences “break-bone fever”. Today, there is no fixed cure for dengue. Keeping the environment safe by spraying pesticides, releasing lots of sterile male mosquitoes and treating the patient in hospitals with OTC medicines are the only options used and available. But, recently, a ground-breaking study, the AWED (Applying Wolbachia to Eliminate Dengue) was published in the New England Journal of Medicine, showed 77% reduction in dengue fever cases by manipulating the dengue mosquito (aedes). This trial was conducted during the World Mosquito Program and took place in the city of Yogyakarta, Indonesia, where the scientists claimed that this “miraculous” bacteria can be the solution to the dengue virus that has been around in the world for a long time now.
How Wolbachia bacteria reduces dengue infection?
Wolbachia does not hurt the mosquito, but it does accumulate in the exact areas of its body where the dengue virus needs to enter. Because the bacteria fight for resources and make it difficult for the dengue virus to multiply, the mosquito is less likely to transmit an infection the next time it bites. Wolbachia can also manipulate the fertility of their hosts in order to ensure that they are passed on to the following generation of mosquitoes. It means that once Wolbachia has been established, it should be able to protect against dengue infection for a long time.
The AWED Trial
Five million Wolbachia-infected mosquito eggs were used in the study. Every two weeks, eggs were dropped in buckets of water across the city, and the process of infecting the population with dengue took nine months. The city of Yogyakarta was divided into 24 zones, with mosquitoes released in only half of them. When the insects were unleashed, there was a 77 percent reduction in fever cases and an 86 percent reduction in persons needing hospitalizations. Dr. Anders, who is also the director of impact assessment at the World Mosquito Program, 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.”
Disease modelling studies have also predicted Wolbachia could be enough to completely suppress dengue fever if it can be established. David Hamer, a professor of global health and medicine at Boston University, said the method had “exciting potential” for other diseases such as Zika, yellow fever and chikungunya; which are also spread by mosquito bites.