Trends of the microcephaly and Zika virus outbreak in Brazil, January–July 2016

Abstract

In the last two months, there have been indications that the Zika virus epidemic is on the decline in Brazil. We reviewed the surveillance data published by the Brazilian Ministry of Health to assess trends of microcephaly and neurological abnormalities suggestive of congenital infection, as well as Zika virus disease in Brazil as a whole and its various regions. From November 2015 to July 2016, 8301 cases of microcephaly were reported in Brazil, mainly in the Northeast region. The number of newly reported cases is declining throughout the country, except in the Southeast region. The numbers of cases that remain under investigation still represent 37.7% of all reported cases in early July. Meanwhile, from January to June, 2016, 165,241 cases of Zika virus disease were reported in Brazil. The state of Rio de Janeiro (Southeast) experienced the third highest incidence, lagging behind only the states of Bahia (Northeast) and Mato Grosso (Midwest). In early June, the number of new Zika virus cases showed a marked decline in all of the regions, except the North. Although the Zika epidemic seems to be diminishing, continued monitoring and surveillance of reported microcephaly and neurological abnormality cases is essential, and investigation efforts need to be vastly improved, as some states still reported high incidences of Zika disease in the first half of 2016.