Zika virus in Brazil comes from Haiti, study shows

A study conducted by the Oswaldo Cruz Foundation (Fiocruz) in Pernambuco state found that the Zika virus in Brazil was brought over from Haiti. Scientists believe it may have been carried by undocumented immigrants and Brazilian military agents engaged in the peace mission in the Caribbean country.

Among the possibilities considered thus far was that the virus entered the country during the 2014 World Cup through African tourists. Another theory was that the virus was introduced during the World Sprint Canoeing World Championships, held in August, 2014, in Rio de Janeiro, which received a number of participants from several countries in the Pacific affected by the virus.

The Zika virus did not arrive straight from the French Polynesia, where it is originally from, researchers at Fiocruz argue. Before coming to the country, it is believed to have migrated to Oceania, then to Easter Island, from which it headed for Central America and the Caribbean before reaching Brazil, late in 2013. The trajectory coincides with that of other arboviruses, like the ones that cause dengue fever and chikungunya.

“This indicates that Central America and the Caribbean are key routes for the entry of arboviruses in South America—a discovery crucial for epidemiological surveillance and the adoption of measures for curbing and monitoring such diseases, especially in border regions, ports, and airports,” a note from Fiocruz reads.

Also according to Fiocruz, in all cases studied in Brazil, the common ancestor of this kind of virus is a strain from Haiti, a country plagued by a triple epidemics of Zika, dengue, and chikungunya.

Another conclusion drawn by the study is that multiple, independent introductions of the Zika virus took place in Brazil, which refutes the previous belief that a single patient may have brought the disease, which subsequently spread through the country.