Protozoa

(redirected from Protozoan infections)
Also found in: Dictionary, Thesaurus, Encyclopedia.

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]

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]
Enlarge picture
PROTOZOA
Enlarge picture
PROTOZOA
Enlarge picture
PROTOZOA
Enlarge picture
PROTOZOA
Enlarge picture
PROTOZOA
Enlarge picture
PROTOZOA
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.
References in periodicals archive ?
histolytica was 30.5%, this protozoan infection was quite high (60.5%) reported in a survey conducted in Karachi, Pakistan (Bilqees et al., 1982); 36.5% infection in diarreal patients in Karachi (Baqai and Zuberi, 1986); 50.9% in Mirpur Sindh (Tasawar et al., 2006).
The majority (2.6%) of those who had mixed protozoan infections were children between [greater than or equal to] 25 and 48 months.
Cryptosporidiosis and other Intestinal Protozoan Infections in Children Less than one year of age in Mexico City.
The total prevalence of children infected with parasitic infection was 61.6%, the prevalence of helminths infection was 45.6% and protozoan infection was 19.8%.
"Intestinal helminthes and protozoan infections among children of Chechen refugees in Poland" (6) is the title of an original article coming from Poland which offers very important data for the refugees residing in the temporary centers of the country.
(4) Similarly, in KwaZulu-Natal (KZN), the third poorest province in South Africa, with a high prevalence of HIV/AIDS in teenagers and middle-aged adult populations, there are scant data on the prevalence of helminth and protozoan infections.
Protozoan infections were mostly in the internal organs.
Previous reports had suggested that metronidazole was effective in resolving lichen planus in patients who did not have any concomitant protozoan infections.
Protozoan infections, such as schistosomiasis, are major causes of crippling illness.
Of 89 adults and adolescents diagnosed with these protozoan infections and enrolled in the randomized, double-blind, placebo-controlled study, those treated with nitazoxanide 500 mg twice daily for 3 days fared significantly better than those in the placebo group.
The differential diagnosis includes all granulomatous bacterial, fungal, or protozoan infections; vasculitis; and neoplastic processes affecting the nose and upper airways, including the lips and soft palate.