Epidemiological Update - Zika Virus Infection - 25 August 2017

Situation Summary in the Americas

Since epidemiological week (EW) 44 of 2016, no additional countries or territories of the Americas have confirmed autochthonous, vector-borne transmission of Zika virus disease. To date, 48 countries and territories in the Americas have confirmed autochthonous, vectorborne transmission of Zika virus disease, while five countries have reported sexually transmitted Zika cases.

North America

In the United States of America, the Florida Department of Health reported that Florida no longer has any identified areas with active Zika transmission, and cases of local transmission have not been reported in 2017. In EW 30 of 2017, the Texas Department of Health and Hidalgo county reported a probable case of local vector-borne transmission that occurred in 2017.

In Mexico, an increase of confirmed cases was observed between EW 16 and EW 27 of 2017 (Figure 2), a trend similar to that observed for dengue in the country during the same period. Approximately 51% of the confirmed Zika cases in the first 32 weeks of 2017 correspond to the states of Nayarit (171 cases), Tamaulipas (146 cases) and San Luis Potosí (123 cases), while the number of confirmed cases in those states is higher than reported in 2015-2016.

Central America

From EW 20 to EW 30 of 2017, a small surge in suspected and confirmed cases was observed in the sub-region due to a slight increase reported in Belize and Costa Rica, with an average of 117 suspected and confirmed cases between EW 21 and EW 30 of 2017 in this sub region (Figure 3).


In countries and territories of this sub region, sporadic cases continue to be reported, with a weekly average of 252 suspected and confirmed cases reported between EW 21 and EW 30 of 2017. In Puerto Rico, the trend of cases observed in the last 10 weeks is decreasing.

South America

From EW 14 of 2017, a decreasing trend of suspected and confirmed cases has been observed in South America (Figure 4), with the exception of Ecuador where an increase in the number of suspected and confirmed cases between EW 4 and EW 20 of 2017 was reported. Between EW 21 and EW 30 of 2017, an average of 293 suspected and confirmed cases were reported per week in this sub-region.