(2012b), Torgerson and Mastroiacovo (2013), World Health Organization (2013).

protoplasmic level

protoplasmic grade

• 1.1. Malaria. Malaria is the most significant of the protozoan parasites that infect man.
• 1.2. African trypanosomiasis.
• 1.3. Chagas disease.
• 1.4. Leishmaniasis.
• 1.5. Toxoplasmosis.
• 1.6. Cryptosporidiosis.

Protozoa (pronounced: pro-toe-ZO-uh) are one-celled organisms, like bacteria. But they are bigger than bacteria and contain a nucleus and other cell structures, making them more similar to plant and animal cells.

Some examples of protozoa are Amoeba, Paramecium, Euglena and Trypanosoma. In some systems of biological classification, Protozoa remains a high-level taxonomic group. When first introduced by Georg Goldfuss in 1818, Protozoa was erected as a class within the animals, and its etymology is literally “first animals”.

There are four groups of protozoa:

• Amoeboid Protozoans: Amoeboid protozoans live in fresh or sea water or in moist soil.
• Flagellated Protozoans: Flagellated protozoans are either free-living or parasitic.
• Ciliated Protozoans: These protozoans have numerous cilia on their body.
• Sporozoans:

Protozoa are single celled organisms. They come in many different shapes and sizes ranging from an Amoeba which can change its shape to Paramecium with its fixed shape and complex structure. They live in a wide variety of moist habitats including fresh water, marine environments and the soil.

The following is a list of some of the common protozoan and algal microbes we share the world with.

• Paramecia. Paramecium caudatum (highly magnified). John J.
• Amoeba. amoeba. Amoeba (Amoeba proteus).
• Euglena. Euglena. Euglena gracilis (highly magnified) in fresh water.
• Diatoms. diatoms.
• Volvox. Volvox.

Protozoa are single-celled eukaryotes (organisms whose cells have nuclei) that commonly show characteristics usually associated with animals, most notably mobility and heterotrophy. They are often grouped in the kingdom Protista together with the plant-like algae and fungus-like water molds and slime molds.

Protozoa: These are unicellular microscopic organisms similar to animals that can move about to capture food and are heterotrophic in nature. They are mostly aquatic in nature. Amoeba, paramecium are some examples of protozoa.

For our purposes, there are only 4 groups of protozoa that will be covered here: these groups are separated by motility and cell structure.

• Amebas (representative: Ameba proteus)
• Flagellates (representative: Trypanosoma, Euglena)
• Ciliates (representative: Paramecium)
• Apicomplexa (representative: Plasmodium)

Many of the most prevalent and deadly human diseases are caused by a protozoan infection, including African Sleeping Sickness, amoebic dysentery, and malaria.

Protozoa can be seen in the drop of water. Sketches of the protozoa are drawn as observed under the microscope. They are identified by comparing their structures with those of different protozoa available in the literature (Figure 9.1).

Protozoa are unicellular eukaryotic microorganisms lacking a cell wall and belonging to the Kingdom Protista. Protozoa reproduce asexually by fission, schizogony, or budding. Some protozoa can also reproduce sexually. Relatively few protozoa cause disease.

Protozoan, organism, usually single-celled and heterotrophic (using organic carbon as a source of energy), belonging to any of the major lineages of protists and, like most protists, typically microscopic. All protozoans are eukaryotes and therefore possess a “true,” or membrane-bound, nucleus.

Protozoans play important roles in the fertility of soils. By grazing on soil bacteria, they regulate bacterial populations and maintain them in a state of physiological youth—i.e., in the active growing phase. This enhances the rates at which bacteria decompose dead organic matter.

Characteristics of Protozoa

Protozoan infections last as long as the single-celled parasites responsible for the condition continue to live in the body. Once introduced into a host, parasites will multiply and thrive until medication is given that kills them.

Protozoa that spread through unclean food or water usually affect the digestive system by living and multiplying in the intestines. Other organs can be affected as well as the parasite spreads. Protozoa that are transmitted through an insect bite usually cause a fever and inflammation among other physical problems.

Leishmaniasis is caused by a protozoa parasite from over 20 Leishmania species. Over 90 sandfly species are known to transmit Leishmania parasites. There are 3 main forms of the disease: Visceral leishmaniasis (VL), also known as kala-azar is fatal if left untreated in over 95% of cases.

Drinking water is disinfected to destroy or inactivate the micro-organisms that are not filtered out. Chlorine is the most common disinfectant in the world.

Not restricted to underdeveloped countries, parasites exist around the world and can afflict anyone of any race, gender or socioeconomic status. They can cause a myriad of symptoms, only a few of which affect the digestive tract, but the good news is that yes, they are treatable.

You might have anal itching, especially at night. You could also have stomach pain, nausea, or vaginal itching. Sometimes pinworms can be seen around your anus or on your underwear or bed sheets about 2 to 3 hours after you’ve gone to bed.

Common symptoms of intestinal worms are:

• abdominal pain.
• diarrhea, nausea, or vomiting.
• gas/bloating.
• fatigue.
• unexplained weight loss.
• abdominal pain or tenderness.