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.
The development of disease depends on factors of the host, parasite and environment. Studies often focus on one of these components, or the interaction between two, with relatively few studies considering all three components (illustrative references are provided in brackets). (Online version in colour.)
