Protozoa are single-celled
microorganisms. While many protozoa benefit man by feeding on
bacteria, others are parasitic to humans and animals and cause serious
Protozoa are more complex
than bacteria. The genetic material (contained in chromosomes) of protozoa
is separated from the cell fluid (cytoplasm) by a double membrane layer.
Also, the cytoplasm of protozoa is more highly organized, similar to
the situation in animal cells.
There are many sources of
infection from parasitic protozoa. Sources of infection include, but
are not limited to, contaminated food or water, infected animals or
In this part of our lesson
on infectious agents, we will discuss some common parasitic protozoa
and how to protect yourself from infection.