Human Disease Caused by Protozoa

Protozoa are single-celled organisms that often have flagella, cilia or other structures that help them to move. The organisms sometimes form parasitic relationships with humans and cause diseases or infections.

Giardiasis

• Caused by the intestinal protozoa Giardia lamblia, giardiasis is an infection that can be spread through food, water, soil or surfaces. People who suffer from giardiasis often develop diarrhea, gas, abdominal cramps, nausea and/or dehydration.

African Sleeping Sickness

• African sleeping sickness is caused by the protozoa Trypanosoma brucei rhodesiense and is spread through the tsetse fly. The disease is common in sub-Saharan Africa, especially in rural areas. The disease affects the central nervous system, causing people to develop a fever, headaches, itching, coordination and balance problems, confusion and/or reduced mental facilities; without treatment it is fatal.

Malaria

• Malaria is a fatal disease that can be caused by one of four types of protozoa in the Plasmodium genus and is spread through the anopheles mosquito. The disease is often found in people in sub-Saharan Africa and South Asia. Symptoms of malaria include muscle aches, nausea, vomiting, diarrhea, jaundice, seizures, anemia, fatigue and/or confusion.

Leishmaniasis

• Found mostly in people in the Middle East, South America, Mexico, Central America and Southeastern Asia, leishmaniasis is caused by one of 20 types of protozoa in the Leishmania genus. People with leishmaniasis often develop sores and/or ulcers, swollen glands, weight loss, a fever and/or an enlarged spleen.

Vaginitis

• Vaginitis, or inflammation of the vagina, is sometimes caused by the protozoa Trichomonas vaginalis and spread through sexual intercourse. The condition causes people to experience vaginal itching, painful sensations during sex, pain during urination and/or vaginal discharges.