What are parasitic diseases?
A parasite is any organism that lives on or inside another organism (the host) and benefits at the host’s expense. They can enter the body through the mouth to reside in the intestines or even burrow through the intestinal wall to infect other organs. Parasites can bore directly through the skin or can enter via the bites of insects. Some can enter the soles of the feet while barefoot or through skin from water that has parasites.
In developed areas, parasites occur in immigrants, returning travelers, and those who have immunosuppression.
Parasites can cause signs and symptoms ranging from skin irritations to serious life-threatening illnesses, including sepsis, blood disorders, lung and gastrointestinal illness, and central nervous system infections.
Categories of parasites include
- Worms (helminths)
Protozoans are microscopic one-celled organisms which can cause a serious infection with just one organism. Route of transmission is fecal-oral (contaminated food or person-to-person contact). They can pass from person to person via mosquitoes or sand flies.
- Ameba: Such as Entamoeba
- Flagellates: Such as Giardia andLeishmania
- Ciliates: Such as Balantidium
- Sporozoa: Such as Plasmidium
Helminths are large organisms visible to the naked eye as adults.
- Flatworms: Tapeworms and flukes can live in the gastrointestinal tract
- Thorny-headed worms: Live in the gastrointestinal tract
- Roundworms (nematodes) such as segmented worms, leeches: They can live in the gastrointestinal tract, blood, lymphatic or subcutaneous tissues
Ectoparasites are typically blood-sucking parasites.