Protozoa


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Protozoa

 [pro″to-zo´ah]
a subkingdom (formerly a phylum) comprising the unicellular eukaryotic organisms; most are free-living, but some lead commensalistic, mutualistic, or parasitic existences. According to newer classifications, the Protozoa are divided into seven phyla: Sarcomastigophora, Labyrinthomorpha, Apicoplexa, Microspora, Acetospora, Myxozoa, and Aliophora. Pathogenic protozoa include Plasmodium species, the cause of human malaria; Trypanosoma gambiense, the cause of African trypanosomiasis; Toxoplasma gondii, of which house cats are the reservoir and humans the intermediate host; Entamoeba histolytica, the cause of amebic dysentery; and Balantidium coli and Isospora belli, both of which cause diarrhea in humans.

Protozoa can be ingested and transmitted through contaminated feces. Prevention of transmission is extremely important; handwashing and stool precautions are recommended. Other necessary precautions (see infection control) should be carried out according to directions from the Centers for Disease Control and Prevention. Protozoal infections are occurring more frequently in North America and other industrialized countries because of increased world travel.

protozoa

 [pro″to-zo´ah]
plural of protozoon.

Pro·to·zo·a

(prō'tō-zō'ă),
Formerly considered a phylum, now regarded as a subkingdom of the animal kingdom, including all of the so-called acellular or unicellular forms. They consist of a single functional cell unit or aggregation of nondifferentiated cells, loosely held together and not forming tissues, as distinguishes the Animalia or Metazoa, which include all other animals. Protozoa were formerly divided into four classes: Sarcodina, Mastigophora, Sporozoa, and Ciliata; new classifications employ higher taxa (phyla, subphyla, and superclasses) and a number of major subdivisions.
[proto- + G. zōon, animal]

Protozoa

/Pro·to·zoa/ (-zo´ah) a subkingdom comprising the simplest organisms of the animal kingdom, consisting of unicellular organisms ranging in size from submicroscopic to macroscopic. It comprises the Sarcomastigophora, Labyrinthomorpha, Apicomplexa, Microspora, Acetospora, Myxozoa, and Ciliophora.

protozoon

[prō′təzō′ən] pl. protozoa
Etymology: Gk, protos + zoon, animal
a unicellular protist that ingests food. Protozoa include free-living forms, such as amebas and paramecia, as well as parasites. Approximately 30 protozoa are pathogenic to humans, including Plasmodium, which causes malaria, and Trypanosoma, which causes sleeping sickness. See also mastigophora. protozoal, protozoan, adj.

Pro·to·zo·a

(prō'tō-zō'ă)
Formerly considered a phylum, now regarded as a subkingdomof the animal kingdom, including all of the so-called acellular or unicellular forms. Members consist of a single functional cell unit or aggregation of nondifferentiated cells, loosely held together and not forming tissues.
[proto- + G. zōon, animal]

Protozoa

(prōt″ă-zō′ă) [ proto- + -zoa]
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The phylum of the kingdom Protista that includes unicellular, animal-like microorganisms. Many protozoa are saprophytes that live on dead matter in water and soil. Many parasitic protozoa infect only humans without adequate immunological defenses although a few infect the immunocompetent. Infections are spread by the fecal-oral route, through ingestion of food or water contaminated with cysts or spores, or by the bite of a mosquito or other insect that has previously bitten an infected person. Common protozoan infections include malaria (Plasmodium vivax, P. malariae); gastroenteritis (Entamoeba histolytica, Giardia lamblia); leishmaniasis, an inflammatory skin or visceral disease (Leishmania species); sleeping sickness (Trypanosoma brucei gambiense, T. b. rhodiense); and vaginal infections (Trichomonas vaginalis). Pneumocystis jiroveci, previously classified as a protozoon, is now categorized as a fungus. Opportunistic protozoan infections caused by Cryptosporidium parvum and Toxoplasma gondii are seen in patients who are immunosuppressed by disease or drug therapy. See: illustration; table
SubphylumGenus and SpeciesDisease Caused
Zoomastigophora (Mastigophora)Giardia lambliaGastroenteritis
Locomotion by flagellaLeishmania donovaniKala azar
Leishmania braziliensisAmerican leishmaniasis
Leishmania tropicaOriental sore
Trichomonas vaginalisTrichomoniasis
Trypanosoma brucei gambiense, Sleeping sickness
T. b. rhodiense
Trypanosoma cruziChagas' disease
Rhizopoda (Sarcodinae)Acanthamoeba castellaniAmebic meningoencephalitis
Locomotion by pseudopodiaA. culbertsonii
A. astromyxis
Dientamoeba fragilisDiarrhea, fever
Entamoeba histolyticaAmebic dysentery
Naegleria fowleriAmebic meningoencephalitis
Apicomplexa (Sporozoa)Babesia microtiBabesiosis
No locomotion in adult stageB. divergens
Cryptosporidium parvumCryptosporidiosis
Cyclospora cayetanensisDiarrhea, gastroenteritis
Isospora belliDiarrhea
Microspora(multiple spp.)Diarrhea, chronic
Plasmodium malariaeQuartan malaria
Plasmodium falciparumMalignant tertian malaria
Plasmodium vivaxTertian malaria
Plasmodium ovaleTertian malaria
Toxoplasma gondiiToxoplasmosis
CiliophoraBalantidium coliBalantidiasis
Possession of cilia in some stage of life cycle

protozoa

Primitive, single-celled, microscopic animals able to move by amoeboid action or by means of CILIA or whip-like appendages (flagella). Many protozoa are parasitic on humans and are of medical importance. These include the organisms that cause AMOEBIASIS, BALANTIDIASIS, CRYPTOSPORIDIOSIS, GIARDIASIS, ISOSPORIDIOSIS, LEISHMANIASIS, MALARIA, SLEEPING SICKNESS, TOXOPLASMOSIS and TRICHOMONIASIS.

Protozoa

Group of extremely small single cell (unicellular) or acellular organisms that are found in moist soil or water. They tend to exist as parasites, living off other life forms.

Protozoa

a phylum comprising the unicellular eukaryotic organisms; most are freeliving, but some lead commensalistic, mutualistic, saprophytic or parasitic existences. Subphyla of veterinary interest include: (1) Sarcodina—including coccidia, cryptosporidia, Toxoplasma, Babesia, Plasmodium and others; (2) Mastigophora—including trypanosomes, Histomonas, Trichomonas spp.
Pathogenic protozoa for animals include: Acanthamoeba, Babesia, Balantidium, Besnoitia, Chilomastix, Cochlosoma, Cryptobia, Cryptosporidium, Cystoisospora, Dientamoeba, Eimeria, Encephalitozoon, Endolimax, Entamoeba, Frenkelia, Giardia, Haemoproteus, Hammondia, Hartmannella, Hepatozoon, Hexamita, Histomonas, Iodamoeba, Isospora, Klossiella, Leishmania, Leucocytozoon, Naegleria, Parahistomonas, Pentatrichomonas, Plasmodium, Sarcocystis, Theileria, Toxoplasma, Trichomonas, Tritrichomonas, Trypanosoma, Tyzzeria and Wenyonella spp.
References in periodicals archive ?
The importance of methanogens associated with ciliate protozoa in ruminal methane production in vitro.
While many protozoa are free-living, the flagellate protozoan symbionts of lower termites are only found in the digestive tract of their host.
Overall, the densities of fern-associated protozoa are reasonably similar to that found in other plant communities, but as discussed below in some cases they exceeded the densities associated with seed plants in organically enriched soils.
This medication, which is aniseed flavoured, will rid the body of the protozoa.
Radiolarians, since you ask, are microscopic, single-celled protozoa distinguished by a spherical or helmet-like skeleton.
This includes a look at viruses and protozoa, the significance of Legionella to the food industry, issues of concern to the fresh produce sector, and international developments with microbiological method validation and microbiological risk assessment.
Biofilm forms when bacteria adhere to surfaces in aqueous environments and begin to excrete a slimy, glue-like substance that anchors them to the inner walls of plumbing pipes; a biofilm can be formed by a single bacterial species but more often consists of many species of bacteria, as well as fungi, algae, protozoa, debris, and corrosion products).
One of the researchers explains, "By using the structure of many protozoan DHFR-TS enzymes, we've been able to place a number of protozoa in distinct evolutionary families.
The film montages fleeting shots of teeming aqueous activity--fizzing protozoa, slimy bacteria, microscopic driftwood eddying in the current--which even in silence walks a line between luxuriant and repulsive, an indecision that Marshall echoes by cutting so that the micro-life seems to be constantly changing direction.
There are alternatives to these traditional approaches, including the use of constructed wetlands, which use plants to create favorable conditions for enzymes, bacteria, protozoa, and fungi that break down and digest organic pollutants.
The easy-to-use filter fits into a portable sport bottle and is capable of treating up to 75 gallons of water, In addition to anthrax spores, the filter removes other bacteria, cysts, and protozoa.
Targeted to scientists, researchers and academics, the journal carries reports of basic research on eukaryotic microorganisms such as yeasts, fungi, algae, protozoa and social amoebae.