Zika Circulates Among Wild Animals in the Americas

Credit: John Tann, Flickr

A collaborative group of researchers from The University of Texas Medical Branch at Galveston and the Faculty of Medicine of Sao Jose do Rio in Brazil is the first to report that wild monkeys in the Americas are transmitting the Zika virus to humans via mosquitoes, making complete eradication of the virus in the Americas very unlikely. The paper is currently available in Scientific Reports.

"Our findings are important because they change our understanding of the ecology and transmission of Zika virus in the Americas," said senior author Nikos Vasilakis, UTMB professor in the department of pathology. "The possibility of a natural transmission cycle involving local mosquitoes and wild local primates as a reservoir and amplification host will definitely impact our predictions of new outbreaks in the Americas, because we cannot eradicate this natural transmission cycle."

Vasilakis said that as yellow fever has shown, disease outbreaks among animals will always be a source of epidemics in humans, even after a possible control and suppression of urban transmission through vaccination and treatments is established.

In two Brazilian cities, the research team identified wild non-human primate carcasses that tested positive for the American Zika virus lineage. In order to learn more about Zika infection in these animals, the researchers infected four primates with the American lineage Zika virus in a laboratory. The monkeys maintained their viral levels over time, suggesting that non-human primates may be a vertebrate host in the maintenance of Zika virus transmission and circulation in urban tropical communities.

"This is a game changer for people involved with disease control—including vaccine developers, public health officials and policy makers," said senior author Mauricio Lacerda Nogueira, a professor from the Faculty of Medicine of Sao Jose do Rio in Brazil. "This work also highlights the value of the longstanding collaboration between the Faculty of Medicine of São José do Rio Preto and UTMB as well the critical importance of our respective funding agencies, the National Institutes of Health and the Sao Paulo Research Foundation in Brazil, who recognized the importance of this issue early."