MIAMI: A bacterium known as Wolbachia, which is fairly common in insects, can reduce mosquitoes’ ability to spread the Zika virus, researchers said Wednesday. The study in the journal Cell Host and Microbe is the first to report on the effect of Wolbachia on Zika, which can cause birth defects in babies if their mothers are infected while pregnant. For the study, researchers in Brazil gave field mosquitoes and Wolbachia-infected mosquitoes the Zika virus by feeding them human blood infected by two recent strains of the virus that is circulating in Brazil. After two weeks, researchers said that mosquitoes carrying Wolbachia had fewer viral particles in their bodies. Also, the virus in their saliva was not active and could not transmit Zika. Similar tests have previously been done using the bacteria to slow the spread of dengue fever and chikungunya.