Number of Zika virus cases in the U.S. from 2015 to 2024
In 2023, there were just seven confirmed cases of Zika virus in the United States, all of which were travel-associated. This is a huge decrease from 2016 when an outbreak of Zika resulted in over 5,000 cases in the United States and thousands more in South America, especially in Brazil. Zika virus can be transmitted through mosquito bites, from a pregnant woman to her fetus, through sex, and likely through blood transfusion.
The Zika virus in the United States
At the height of the latest Zika outbreak in the United States in 2016, almost every U.S. state reported cases of Zika virus infection, with the states of Florida and New York reporting the highest numbers with each over 1,000 cases. However, the vast majority of those cases were travel associated. Although most people with Zika virus only have mild symptoms, if at all, Zika infection during pregnancy can cause severe birth defects, including microcephaly. From January 2016 to June 2017, it was estimated that around 2,667 live births in the United States had brain abnormalities and/or microcephaly potentially related to Zika virus.
The Zika virus in Brazil
The latest Zika virus outbreak began in Brazil in 2015 with cases peaking in the country in 2016. In 2016, there were almost 274 thousand cases of Zika virus in Brazil. However, cases decreased significantly in 2017. In 2023, Brazil reported around 35 thousand Zika virus cases. Although the entire country has been impacted by the virus, certain areas have been affected more than others. In 2017, the Central-West of the country reported the most cases, but from 2019 to 2022 the Northeast saw the highest number of cases. Reported cases of microcephaly also peaked in 2016 with 2,276 such cases. By 2023, this number had dropped to just 318.
