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What are Protozoan Parasites?

Thomma Grindstaff
Thomma Grindstaff

Protozoan parasites are eukaryotes, or one-celled organisms that have well-developed structures inside membranes. As parasites, they obtain food and protection by dwelling inside other organisms, referred to as hosts. If they get inside a human host, these parasites can cause a wide variety of problems. Some protozoan parasites are responsible for serious and sometimes deadly diseases. Others, such as those that infect the gastrointestinal tract, cause troublesome symptoms but usually do not prove fatal.

These parasites can be found everywhere: in water, food and soil. When they infect their hosts, protozoan parasites are usually in cyst form, a dormant state in which the organism has encased itself in a tough membrane. As a cyst, the parasite can survive harsh conditions and live a long time before finding a host. After the parasite finds a home in a host, it changes its form in order to get nutrition and reproduce itself.

Giardia lamblia is an intestinal protozoan parasite.
Giardia lamblia is an intestinal protozoan parasite.

There are many types of parasites. Intestinal parasites are a worldwide problem, especially in places where water and food sources are contaminated. One intestinal protozoan parasite, Entamoeba histolytica, is found in tropical and subtropical areas and is responsible for amoebic dysentery. Another intestinal parasite, Giardia lamblia, is common in temperate areas. It usually affects outdoorsy people like hikers and campers who drink unsafe water in remote regions.

If malaria is contracted, it must be treated with anti-malaria medication as soon as possible.
If malaria is contracted, it must be treated with anti-malaria medication as soon as possible.

Other protozoan parasites infect the blood. Some of the most dangerous of these parasites are those that cause African sleeping sickness, malaria and leishmaniasis, a disease whose initial symptoms include sores on the skin that spread over time and damages the liver and the spleen. The parasitic protozoa that cause these illnesses need intermediary organisms like insects to infect human hosts. African sleeping sickness requires tsetse flies, malaria requires mosquitoes, and leishmaniasis requires sand flies.

A blood sample may be used to detect protozoan parasites that have colonized a patient's blood.
A blood sample may be used to detect protozoan parasites that have colonized a patient's blood.

Treating protozoan parasites depends on the type of parasite and which disease it causes. For example, giardiasis and amoebic dysentery are treated with antiprotozoal medication such as metronidazole. Malaria must be treated with antimalarial medication as soon as it is detected. African sleeping sickness responds to medicines that contain arsenic.

Parasites that infect the blood may cause symptoms like chills and fever.
Parasites that infect the blood may cause symptoms like chills and fever.

Symptoms of protozoan parasites differ, depending on the parasite. Intestinal parasites cause vomiting and diarrhea, while parasites that infect the blood cause symptoms like chills, fever and headache. All parasitic infections are serious conditions. People who have a protozoan infection must see their doctors as soon as possible for prompt treatment. To prevent infection by protozoan parasites, it is recommended that people wash their hands regularly, avoid putting their hands in their mouths, and drink only water that has been treated.

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    • Giardia lamblia is an intestinal protozoan parasite.
      By: Iqbal Osman
      Giardia lamblia is an intestinal protozoan parasite.
    • If malaria is contracted, it must be treated with anti-malaria medication as soon as possible.
      By: alejandro dans
      If malaria is contracted, it must be treated with anti-malaria medication as soon as possible.
    • A blood sample may be used to detect protozoan parasites that have colonized a patient's blood.
      By: Goran Bogicevic
      A blood sample may be used to detect protozoan parasites that have colonized a patient's blood.
    • Parasites that infect the blood may cause symptoms like chills and fever.
      By: JackF
      Parasites that infect the blood may cause symptoms like chills and fever.
    • Intestinal parasites are a worldwide problem.
      By: 7activestudio
      Intestinal parasites are a worldwide problem.
    • Parasites that infect the blood may cause symptoms like headache.
      By: WavebreakMediaMicro
      Parasites that infect the blood may cause symptoms like headache.
    • Malaria kills approximately a million people per year.
      By: claffra
      Malaria kills approximately a million people per year.