Uncovering the hidden spread of Zika in Brazil

In February 2016 Zika was declared a public health emergency by the World Health Organisation (WHO) in response to evidence that the infection can cause birth defects such as severe microcephaly in the foetuses of infected pregnant women.

An international research collaboration travelled across northeast Brazil in a minbus equipped with cutting-edge mobile DNA sequencing capabilities and tested samples from more than 1,300 patients infected with the virus.

By carrying out genome sequencing to understand the virus’ genetic make-up, the team were able to track the spread of the virus across Brazil, showing that Zika was present in Brazil for a full year prior to the first confirmed cases in May 2015. Northeast Brazil was the nexus of the epidemic and played a key role in its spread within Brazil to major urban centres, such as Rio de Janeiro and São Paulo, before spreading across the Americas.

Dr. Nuno Faria, of the University of Oxford’s Department of Zoology, said: “A better understanding of Zika virus’ genetic diversity is critical to vaccine design, and also to identify areas where surveillance is most needed”.

The project was funded by the Medical Research Council’s Zika Rapid Response Initiative, USAID, and supported by the Wellcome Trust and the Newton Fund. It was led by the Universities of Birmingham and Oxford in partnership with FioCruz Bahia, the University of São Paulo, and supported by the Brazilian Ministry of Health.