Table of ContentsView AllTable of ContentsWhat Are Protozoa?DiseasesDiagnosisTreatmentFrequently Asked Questions
Table of ContentsView All
View All
Table of Contents
What Are Protozoa?
Diseases
Diagnosis
Treatment
Frequently Asked Questions
Protozoaare a group of 65,000 (or possibly more) single-cell organisms. They are part of what’s called the eukarya domain and include the cells that make up humans, animals, plants, fungi, and parasites.
Most humans will “host” a protozoa in or on their body at some point in their life. While not all protozoans found in the environment are dangerous, some cause diseases like malaria and giardia, both of which can lead to diarrhea.
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This article explains the role of protozoa in infectious disease and how protozoan diseases are treated.
Protozoa are broken down into different classes:
Protozoa cause some common and some uncommon infections. Some of these infections cause illness in millions of people each year; other diseases are rare.
Protozoan Diseases
These infections arise in very different parts of the body. For example, malariainfections start in the blood, giardia begins in the gut, and toxoplasmosis can infect lymph nodes, the eye, and the brain.
Less common protozoan diseases includeAfricantrypanosomiasisandamoebicdysentery.
African Trypanosomiasis
The flies that spread sleeping sickness live in at least 36 countries. The disease causes serious neurologic effects, and the treatment is complex. In poorer, resource-limited areas, it’s hard to identify and treat.
Most cases occur in the Democratic Republic of the Congo, where people are working to reduce the spread of the disease and its burden—and possibly even drive these protozoa into extinction.
Amoebic Dysentery
Amoebic dysentery is due toEntamoeba histolytica,which causes diarrhea and gastrointestinal upset.It can also travel through the walls of the intestines and go into the bloodstream and other organs, like the liver, where it can create liver abscesses.
RecapCommon protozoan infectious diseases include malaria, giardia, and toxoplasmosis. Less common diseases include African trypanosomiasis and Amoebic dysentery. Each condition affects the body differently.
Recap
Common protozoan infectious diseases include malaria, giardia, and toxoplasmosis. Less common diseases include African trypanosomiasis and Amoebic dysentery. Each condition affects the body differently.
Detecting Infections
Unlike other pathogens, cultures do not identify protozoa. However, sometimes you can see them under a microscope inside red blood cells (as in malaria) or in the stool (as in giardia andE.histolytica).
In addition, rapid blood tests for antibodies or antigens and PCR tests can detect their genetic material.
Toxoplasmosis
Healthcare providers can identify toxoplasmosis in several different ways depending on where it’s causing an infection, including:
Giardia
Entamoeba Histolytica
E. histolyticacan also be identified from stool samples. It may also be identified under a microscope, through a PCR test, antigen test, or an antibody test of the blood.
Human African Trypanosomiasis
Diagnosing human African trypanosomiasis involves blood tests, fluid tests, or a biopsy from a lymph node (or a chancre wound).
Trypanosoma Brucei Rhodesiense
T. b.rhodesienseparasites can usually be found in the blood of infected people.
Trypanosoma Brucei Gambiense
T. b.gambiensehas a lower burden of protozoa in the blood, so blood microscopy is usually unable to identify it. However, microscopic examination of a lymph node biopsy is more likely to identify the infection.
RecapDiagnosing protozoan diseases may involve blood tests, stool tests, or biopsies. A healthcare provider will decide which test is appropriate based on which protozoa they suspect.
Diagnosing protozoan diseases may involve blood tests, stool tests, or biopsies. A healthcare provider will decide which test is appropriate based on which protozoa they suspect.
Treatment options depend on what protozoa are infecting you. Some are a lot more successful than others.
For example, malaria is a common illness worldwide that hasstraightforward treatment. However, the treatment depends on the type of malaria (Plasmodium falciparum,Plasmodiumknowlesi,Plasmodiummalariae,Plasmodiumovale, andPlasmodium vivax).
Treatment also depends on whether the protozoa are drug-resistant.P. falciparumespecially has grown resistant to some essential drugs over the last few decades.
Summary
Protozoa are single-celled organisms that can sometimes cause diseases. Common protozoan diseases include malaria, giardia, and toxoplasmosis. Diagnosing protozoan illness may involve blood tests, stool tests, or biopsies, depending on which protozoa a healthcare provider suspects. Treatment varies based on the cause.
Frequently Asked QuestionsProtozoa are microscopic, single-celled organisms. Protozoa can multiply in humans and transmit from one person to another.They can cause parasitic infectious diseases like malaria, giardia, and toxoplasmosis.There are four types or classes of protozoa. These include the sporozoa (intracellular parasites), flagellates (which use a tail-like structure to move), amoebas (which move using pseudopods or a temporary cell body projection), and ciliates (which move using hair-like structures called cilia).
Protozoa are microscopic, single-celled organisms. Protozoa can multiply in humans and transmit from one person to another.They can cause parasitic infectious diseases like malaria, giardia, and toxoplasmosis.
There are four types or classes of protozoa. These include the sporozoa (intracellular parasites), flagellates (which use a tail-like structure to move), amoebas (which move using pseudopods or a temporary cell body projection), and ciliates (which move using hair-like structures called cilia).
10 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Capela R, Moreira R, Lopes F.An overview of drug resistance in protozoal disease.Int J Mol Sci. 2019 Nov;20(22):5748. doi:10.3390/ijms20225748Hooshyar H, Rostamkhani P, Arbabi M, Delavari M.Giardia lamblia infection: review of current diagnostic strategies.Gastroenterol Hepatol Bed Bench. 2019;12(1):3-12.World Health Organization.Trypanosomiasis, human African (sleeping sickness).Andrews KT, Fisher G, Skinner-Adams TS.Drug repurposing and human parasitic protozoan diseases.Int J Parasitol Drugs Drug Resist. 2014;4(2):95–111. doi:10.1016/j.ijpddr.2014.02.002De waal T.Advances in diagnosis of protozoan diseases. Vet Parasitol. 2012;189(1):65-74. doi:10.1016/j.vetpar.2012.03.033Centers of Disease Control and Prevention.Symptoms of toxoplasmosis.Centers for Disease Control and Prevention.Testing and diagnosis for giardia infection.Centers for Disease Control and Prevention.Diagnosis of sleeping sickness.World Health Organization.Malaria.Centers for Disease Control and Prevention (CDC).About parasites.
10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Capela R, Moreira R, Lopes F.An overview of drug resistance in protozoal disease.Int J Mol Sci. 2019 Nov;20(22):5748. doi:10.3390/ijms20225748Hooshyar H, Rostamkhani P, Arbabi M, Delavari M.Giardia lamblia infection: review of current diagnostic strategies.Gastroenterol Hepatol Bed Bench. 2019;12(1):3-12.World Health Organization.Trypanosomiasis, human African (sleeping sickness).Andrews KT, Fisher G, Skinner-Adams TS.Drug repurposing and human parasitic protozoan diseases.Int J Parasitol Drugs Drug Resist. 2014;4(2):95–111. doi:10.1016/j.ijpddr.2014.02.002De waal T.Advances in diagnosis of protozoan diseases. Vet Parasitol. 2012;189(1):65-74. doi:10.1016/j.vetpar.2012.03.033Centers of Disease Control and Prevention.Symptoms of toxoplasmosis.Centers for Disease Control and Prevention.Testing and diagnosis for giardia infection.Centers for Disease Control and Prevention.Diagnosis of sleeping sickness.World Health Organization.Malaria.Centers for Disease Control and Prevention (CDC).About parasites.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Capela R, Moreira R, Lopes F.An overview of drug resistance in protozoal disease.Int J Mol Sci. 2019 Nov;20(22):5748. doi:10.3390/ijms20225748Hooshyar H, Rostamkhani P, Arbabi M, Delavari M.Giardia lamblia infection: review of current diagnostic strategies.Gastroenterol Hepatol Bed Bench. 2019;12(1):3-12.World Health Organization.Trypanosomiasis, human African (sleeping sickness).Andrews KT, Fisher G, Skinner-Adams TS.Drug repurposing and human parasitic protozoan diseases.Int J Parasitol Drugs Drug Resist. 2014;4(2):95–111. doi:10.1016/j.ijpddr.2014.02.002De waal T.Advances in diagnosis of protozoan diseases. Vet Parasitol. 2012;189(1):65-74. doi:10.1016/j.vetpar.2012.03.033Centers of Disease Control and Prevention.Symptoms of toxoplasmosis.Centers for Disease Control and Prevention.Testing and diagnosis for giardia infection.Centers for Disease Control and Prevention.Diagnosis of sleeping sickness.World Health Organization.Malaria.Centers for Disease Control and Prevention (CDC).About parasites.
Capela R, Moreira R, Lopes F.An overview of drug resistance in protozoal disease.Int J Mol Sci. 2019 Nov;20(22):5748. doi:10.3390/ijms20225748
Hooshyar H, Rostamkhani P, Arbabi M, Delavari M.Giardia lamblia infection: review of current diagnostic strategies.Gastroenterol Hepatol Bed Bench. 2019;12(1):3-12.
World Health Organization.Trypanosomiasis, human African (sleeping sickness).
Andrews KT, Fisher G, Skinner-Adams TS.Drug repurposing and human parasitic protozoan diseases.Int J Parasitol Drugs Drug Resist. 2014;4(2):95–111. doi:10.1016/j.ijpddr.2014.02.002
De waal T.Advances in diagnosis of protozoan diseases. Vet Parasitol. 2012;189(1):65-74. doi:10.1016/j.vetpar.2012.03.033
Centers of Disease Control and Prevention.Symptoms of toxoplasmosis.
Centers for Disease Control and Prevention.Testing and diagnosis for giardia infection.
Centers for Disease Control and Prevention.Diagnosis of sleeping sickness.
World Health Organization.Malaria.
Centers for Disease Control and Prevention (CDC).About parasites.
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