Infectious Disease Terms

Infection - entry and multiplication of a microorganism or parasite in the body of a host.

Infectious disease - infection + evidence of disease.

Contamination - presence of a living agent on the exterior of the body or on an article of clothing.

Reservoir - the normal habitat where the agent lives and multiplies. It is where the agent propagates itself in nature. A dead-end host or temporary resting place of the agent is not a reservoir.

Carrier - a person or animal that harbor an infectious agent yet manifest no discernible signs of infection.

Zoonosis - infections naturally transmitted between animals and humans.

Portal - an entry and exit site into or out of the host for an agent. The six portals for agents are (1) the respiratory tract, (2) the conjunctiva (lining around the eyes), (3) urogenital tract, (4) gastrointestinal tract, (5) tranplacental (mother to child), (6) and skin.

Transmission - the mechanism by which an agent is spread from one host to another. The forms of transmission are described in the book.

Immunity - host factors that alter the likelihood of infection and disease after the agent is encountered.