Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Shape files used in the figure were obtained from https://www.diva-gis.org/gdata. Areas affected by historical outbreaks are indicated by defined polygons in black border lines.
