A study conducted by Brazil’s Oswaldo Cruz Foundation (Fiocruz) and Eliminate Dengue, has confirmed that Wolbachia bacteria can reduce Zika virus transmission by the Aedes aegypti mosquito. The bacterial genus is currently used in regions like Australia, to control the spread of dengue.
“Zika and dengue belong in the same family of viruses so with the Zika outbreak in Brazil, the logical idea was to test the mosquitoes carrying Wolbachia by challenging them with the Zika virus,” said Dr. Luciano Moreira, senior author of the report and head of the Brazilian Eliminate Dengue team. The researchers studied wild Brazilian field mosquitoes and Wolbachia-infected mosquitoes, who were both fed blood infected with the Zika virus.
Not only did the Wolbachia-infected mosquitoes show lower levels of the Zika virus in their saliva, but the virus isolated was not infectious. The researchers are hopeful that this strategy may help block Zika virus transmission, thereby controlling the Zika epidemic.
The Wolbachia bacteria prevents replication of RNA arboviruses, including Zika, dengue and Chikungunya. As the Wolbachia infection is passed from generation to generation through the female mosquito’s egg, this approach could be a self-sustaining, less labor-intensive way to control the spread of these viruses.
This technique has been used since 2011 in Brazil, Colombia, Vietnam, Indonesia and Australia, as a way to control transmission of dengue in these at-risk countries. A trial of the Wolbachia approach in Townsville, Queensland, Australia, has reported that 80 percent of the mosquitoes have been infected with the bacteria just 18 months after it was introduced into the population.
“Wolbachia is sustaining itself at high levels in the majority of these sites up to five years after application. In areas where mosquito populations have high levels of Wolbachia, we haven’t seen any significant local transmission of dengue,” said Professor Scott O’Neill from Monash University, the lead scientist for Eliminate Dengue. “The method we’re using is safe for humans and the environment, and has received widespread international support from governments, regulators and community members.”
This technology is expected to be crucial in the coming months as the Aedes aegypti vector continues to spread through Latin America, and potentially North into the Southern US states. The virus has been linked to serious neurological damage, including microcephaly, and paralysis associated with Guillain-Barré syndrome.