Zika virus – Incidence and trends
To date, 47 countries and territories in the Americas have confirmed autochthonous, vector-borne transmission of Zika virus disease since 2015.1 In addition, five countries in the Americas have reported sexually transmitted Zika cases.2 Since the last Zika Epidemiological Update of 6 October 2016, no additional countries and/or territories have confirmed vector-borne autochthonous transmission of Zika virus in the Americas (Figure 1).
Figure 1. Countries and territories in the Americas with confirmed autochthonous (vector-borne) Zika virus cases, 2015-2016.
Highlighted below is a summary of the Zika epidemiological situation by sub-regions of the Americas.
North America
In Mexico, while a downward trend of confirmed cases has been observed in the last four weeks, from epidemiological week (EW) 36 through EW 39, this may be due to the time between the onset of symptoms and the laboratory confirmation of the case. Since the beginning of the outbreak up to EW 35 of 2016, an upward trend had been observed.
In the United States of America, the U.S. Centers for Disease Control and Prevention (CDC) continues to work with Florida State health authorities to investigate new autochthonous cases of Zika virus. On 14 October 2016, the state of Florida reported Zika virus transmission in a new area within the county of Miami-Dade.
Central America
In Central America, Belize, Guatemala, and Panama have reported an increasing trend in
cases. In the other countries of Central America, the trend continues to decrease.
In Belize, a bimodal epidemic curve with peaks of suspected cases in EW 34 and EW 38 has been reported.
In Guatemala, in the past three weeks an increase of suspected cases is observed, following what had been decrease in cases since EW 22.
Similar to Guatemala, in Panama, a new increase of cases has been observed between EW 30 and EW 36. The following decrease in cases reported between EW 37 and EW 38 is subject to change by retrospective adjustments of the data.
Caribbean
In Anguilla, new cases continue to be reported with an increasing trend in the last four weeks
(EW 37 to EW 40).
In the French overseas territories, Saint Martin has had a decrease of suspected cases between EW 37 and EW 39; this follows the previously reported increase of cases between EW 32 and 36. In Saint Barthelemy circulation of Zika virus remains active with a high number of cases reported in the last two weeks (EW 38 and EW 39), with 40 and 30 suspected cases being reported, respectively.
In Sint Maarten, an independent state within the Kingdom of the Netherlands, bordered to the north by the French territory of Saint Martin, an increase in confirmed cases has been reported in the last two weeks reported (EW 37 and EW 38).
In Puerto Rico, a declining trend in confirmed cases has been observed between EW 35 and EW 39.
Other countries/territories in the Caribbean also show a declining trend of Zika cases.
South America
All countries in South America continue to report decreasing numbers of Zika cases.