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.
A human hand holding three test tubes containing black flies. Verso: WHO/16565. AFRO. Onchocerciasis. Blackflies. The risk of onchocerciasis for the human population can be calculated by counting the blackflies captured at any one point and making an estimate of their total numbers.
Copyright:
TThis item may be under copyright protection; contact the copyright owner for permission before re-use.
Copyright Information:
World Health Organization; World Health Organization website