The epidemiologic triangle consists of three things: agent, host, and environment.
• Agent
The agent is that microorganism which in reality causes the disease. An agent can be any type of bacteria, virus, fungus, or parasite.
• Host
The agent contaminates the host, which is the entity that sustains the disease. A host doesn’t always fall ill; hosts can also be carriers of a disease without showing any indication of being sick.
• Environment
Exterior elements can influence an epidemiologic outburst as well; together these can be known as the environment. The environment incorporates any elements that influence the growth of the disease but are not an agent or the host.