For many years scientists have been studying Wolbachia, looking for ways to use it to potentially control the mosquitoes that spread human diseases. The research has shown that when introduced into the Aedes aegypti mosquito (the primary species responsible for transmitting human viruses such as dengue, chikungunya, and Zika), Wolbachia can stop these viruses from growing inside the mosquito and being transmitted to people.
Wolbachia is a naturally occurring bacterium already found in the environment in many insect species around us, including some mosquitoes. Although the bacterium is common among insects, it is not usually found in the Aedes aegypti.
Wolbachia does not spread through the air, or via insect-to-insect contact. Instead, it is passed on from mother to offspring. Researchers have to infect the mosquito artificially with Wolbachia in the laboratory and then release Aedes aegypti into the wild.
The goal is to reduce infections in humans by getting Wolbachia-infected mosquitoes to mate and pass the bacterium to future generations. When an insect has Wolbachia, the bacterium takes up residence in all of the cells, including a female’s ovaries. That means all her progeny will carry the bacteria, and her daughters will in turn pass it on to their offspring, and so on, until the bacteria spreads throughout the population. If an infected male fertilizes an uninfected female’s eggs, they won’t hatch.
If the method works, vast numbers of wild mosquitoes will eventually carry Wolbachia and thus be unable to transmit dengue. In addition to the field trials being done in Australia for the past five years, trials are under way in Vietnam, Indonesia, Brazil and Columbia.
Wolbachia-infected mosquitoes with strains of Zika virus are currently circulating in Brazil. According to a recent report from Brazil says that mosquitoes infected with Wolbachia had significantly less amounts of the virus in their saliva than normal mosquitoes, indicating that Wolbachia was blocking transmission. (Floro Mercene)
