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.
Modes of agent transmission
| Horizontal |
| Direct transmission |
| Contact (person-to-person) |
| Indirect transmission |
| Common vehicle |
| Single exposure |
| Multiple exposures |
| Continuous exposure |
| Vertical (transmission from one generation to another) |
(modified from ref. 1)
