It’s a disease caused by a living plant or animal called a parasite. The parasite lives in or on the body of another plant or animal and feeds on it’s tissues. In general, all diseases which are caused by living parasites are called parasitic diseases. Bacteria are living parasites, but so many diseases are caused by them that bacterial diseases are usually grouped separately. Parasitic diseases include those caused by plants such as fungi, one celled animals (Protozoa), worms, and insects.
One parasitic disease caused by a fungus is “blastomycosis”. It is a severe skin disease, usually of the hands and face, which often leaves scars. Another disease caused by a fungus is “actinomycosis”, which in cattle and other animals is called “lumpy jaw”. In actinomycosis there are usually severe swellings and abscesses in the mouth and other parts of the body. “Ringworms”, another parasitic disease of man, is caused by a plant fungus. Most diseases caused by fungi can be prevented by cleanliness.
One of the most serious diseases caused by a one celled animal is “Malaria”. Malaria is caused by a protozoan “plasmodium”. Part of the life cycle of this organism is carried out in mosquitoes. The bite of these mosquitoes spreads malaria. “Amebic Dysentery” is a severe protozoan disease of man which is caused by an ameba. It is characterized by diarrhea and bloody stool. Another disease of man and animals caused by Protozoa is “Sleeping Sickness”. The type of Protozoa which causes this disease is called a “Trypanosome”.
Among the parasitic diseases caused by worms are Hookworms, Elephantiasis, and Trichinosis. “Hookworm” is caused by the hookworm, a roundworm that usually enters the body through the feet or legs. The tropical disease, “Elephantiasis”, is caused by a very thin worm, and is transmitted by the bite of mosquitoes. “Trichinosis” is caused by the “Trichina”, a worm found in raw or incompletely cooked pork.
Parasitic skin diseases can be caused by fleas, lice, and bedbugs. “Scabies” is caused by the bites of mites or microscopic spiders. Many diseases caused by bacteria or Protozoa are carried and spread by insects and related animals. Malaria, Yellow Fever, Bubonic Plaque, Typhus, and African Sleeping Sickness are spread by parasitic insects.