Brazil Leads the Americas in Zika Cases in 2025

When visiting countries in the Americas in 2025, travelers to areas where the Zika virus is known to be present are at risk of infection.

However, it can be challenging to determine the exact level of risk in each Zika outbreak.

According to the U.K. Travel Health Pro, those who stay for extended periods in regions where the Zika virus is common face a higher risk. Nevertheless, even short-term visitors may be exposed to the virus, such as in the Federative Republic of Brazil.

As of March 25, 2025, about 2,556 Zika cases have been reported in Brazil since the beginning of 2025.

Most of these cases have been reported in Mato Grosso, São Paulo, Acre, and Rio Grande do Norte. Mato Grosso is a mountainous state in west-central Brazil, mainly covered by the Amazon rainforest.

Just to the south, the Argentine Republic has reported 433 Zika cases this year.

Previously, the U.S. CDC removed a Level 2 Travel Advisory in 2021 regarding Argentina's Zika outbreak.

To the north, in the United States, no Zika cases have been confirmed in 2025.

Last year, the U.S. CDC reported 19 non-congenital Zika cases among U.S. residents, primarily in Puerto Rico.

With millions of international travelers expected to visit these areas in 2025, Zika vaccines will not be available. However, several Zika vaccine candidates are conducting clinical research and aspiring for future U.S. FDA approval.