Zika virus – Incidence and trends
To date, 47 countries and territories in the Americas have confirmed autochthonous, vectorborne transmission of Zika virus disease since 2015. In addition, five countries in the Americas have reported sexually transmitted Zika cases. Since the last Zika Epidemiological Update of 8 September 2016, Saint Kitts and Nevis has confirmed vector-borne autochthonous transmission of Zika virus.
Highlighted below is a summary of the Zika epidemiological situation by sub-regions of the Americas.
North America
From the beginning of the outbreak in Mexico up to epidemiological weeks (EW) 34 there was an increasing trend of confirmed Zika cases, with a decreasing trend of cases in the last three weeks, (EW 34 to 36). The trend will have to be monitored to see if the decrease continues in the coming weeks.
In the United States of America, the area of Zika transmission continues to expand with three counties in the state of Florida reporting autochthonous cases of Zika virus infection: MiamiDade,
Palm Beach, and Pinellas.
Central America
In Central America, an increasing trend of cases has been observed over the last four weeks in Costa Rica, Guatemala, and Nicaragua.
Costa Rica continues to have an increasing trend in cases since the beginning of the outbreak up to EW 32, although in the preceding two weeks (EW 33 and 34) a decrease has been reported; it remains to be seen if this trend will continue.
In Guatemala, following a downward trend that began on EW 23, the reported cases increased again in EW 32.
In Nicaragua, the number of reported cases has mostly been on the rise since the beginning of the outbreak.
In Panama, following a sharp decrease in cases since EW 23, an increase in cases has been observed as of EW 30.
The greatest increase in Zika cases in Central America occurred between late 2015 and early 2016.
Caribbean
In the past four weeks Saint Martin, the French overseas territory, reported an increasing trend in cases after the decrease observed up to EW 32.
Puerto Rico reflects a declining trend of Zika cases in the past three weeks, (EW 33 to EW 35), following the increase in number of cases observed since the beginning of the outbreak.
However, the trend should be monitored over the following weeks to confirm if the declining trend continues in these countries/territories.
Other countries/territories in the Caribbean also show a declining trend of Zika cases.
South America
In South America, all countries are reporting decreasing numbers of Zika cases.