Could Wolbachia Eradicate Zika and Other Mosquito-borne Diseases?

Researchers from the Fundacao Oswaldo Cruz in Brazil have found a potential solution for the troubling spread of Zika virus in the Latin American country and across the hemisphere—and it’s bacteria, specifically Wolbachia.

The group’s findings, which were published online on May 4th by the journal Cell Host & Microbe, have generated new optimism regarding the potential for identifying a solution to the problem of mosquito-borne viruses such as Zika, which have plagued regions across the Americas and have been linked to significant comorbidities. Zika has presented huge challenges for healthcare professionals in Brazil, which is preparing to host the Summer Olympics in August.

“We have been involved in efforts to eliminate the problems posed by Dengue, Chikungunya, and Zika since 2005,” study co-author Luciano Andrade Moreira, PhD, an entomologist and molecular biologist with a specialty in infectious diseases, told Contagion. “We initially demonstrated that mosquitoes infected with Wolbachia were unable to transmit Dengue, and our new research [builds on] that.”

Indeed, researchers from the same group published findings on the wMel strain of the bacteria’s role in controlling Dengue disease transmission in the mid-2000s, and it is already being used as prophylaxis for the virus in multiple countries worldwide. For their most recent project, the team infected a sample population of Aedes aegypti mosquitoes with wMel Wolbachia, a strain of the bacterial endosymbiont present in an estimated 40 percent of all known terrestrial insect species, using 2 currently circulating Brazilian ZIKV isolates (BRPE243/2015 and SPH/2015).

They discovered that among mosquitoes with Zika virus-infected blood, only 10 percent of those that were positive for wMel had disseminated infection and that none had infectious Zika virus in their saliva. In comparison, 80 percent of Wolbachia-negative controls had disseminated infection and 100 percent had infectious Zika virus in their saliva.

Overall, for the BRPE isolate, Wolbachia decreased Zika virus prevalence by 35 percent in abdomens, 100 percent in head/thoraces at 7 dpi, and by 65 percent and 90 percent at 14 dpi, respectively. For the SPH isolate, Wolbachia reduced prevalence by 95 percent and 67 percent in head/thoraces and abdomens, respectively, at 7 dpi, and by 74 percent and 68 percent in head/thoraces and abdomens, respectively, at 14 dpi.

Because of the bacteria’s proven role in preventing Dengue transmission, Dr. Moreira told Contagion that Wolbachia can be used as a relatively inexpensive approach to controlling the spread of Zika as well, particularly when viewed within the context of what governments in the Americas are spending on chemical controls and care for infected patients.

“We are already working with the government in Brazil and with international funders to expand our program,” said Dr. Moreira, who is the lead scientist in charge of Zika control efforts in his native country. “However, we don’t see this as the only solution. Rather, we hope to integrate this approach with different strategies in order to solve the problem of Zika in the Americas.”

Brian P. Dunleavy is a medical writer and editor based in New York. His work has appeared in numerous healthcare-related publications. He is the former editor of Infectious Disease Special Edition.