TYPES OF PATHOGEN/ OR
INFECTIOUS AGENT
WHAT IT IS?
SPEC FC
NAME OF AN
ORGANISM
DISEASE IT CAN
CAUSE
One-celled organism that
found almost everywhere.
2
These organisms are the
human body's worst enemies.
3
A single organism that cannot
make its own food Relies on
other living or dead organisms
to survive
A single-celled organism much
more complex than bacterium.
Protozoan infections usually
come from contaminated
water and food.
An organism that lives in a
host organism and draws
nourishment from it. Some
may be very large​

The process of infection can be broken down into stages, each of which can be blocked by different defense mechanisms. In the first stage, a new host is exposed to infectious particles shed by an infected individual. The number, route, mode of transmission, and stability of an infectious agent outside the host determines its infectivity. Some pathogens, such as anthrax, are spread by spores that are highly resistant to heat and drying, while others, such as the human immunodeficiency virus (HIV), are spread only by the exchange of bodily fluids or tissues because they are unable to survive as infectious agents outside the body.