A parasitic disease is an infectious disease caused or transmitted by a parasite. Many parasites do not cause disease per se. Parasitic diseases can affect practically all living organisms, from plants to mammals. The study of parasitic diseases is called by parasitology.

Some parasites like Toxoplasma gondii can cause disease directly, but other protozoan cause disease by the toxins that they produce.

Although organisms such as bacteria function as parasites, the usage of the term "parasitic disease" is usually more restricted. The three main types of organisms causing these conditions are protozoa, helminths, and ectoparasites.

See also

• Human parasitic diseases

References