It has been suggested that Tachyzoite, Tachyzoites and Bradyzoite be merged into this article or section. (Discuss)

Toxoplasma Gondii
T. gondii tachyzoites
Scientific classification
Kingdom: Protista Phylum: Apicomplexa Class: Conoidasida Subclass: Coccidiasina Order: Eucoccidiorida Family: Sarcocystidae Genus: Toxoplasma Species: T. gondii
Binomial name
Toxoplasma gondii (Nicolle & Manceaux, 1908)

Toxoplasma gondii is a species of parasitic protozoa in the genus Toxoplasma.^[1] The definitive host of T. gondii is the cat, but the parasite can be carried by the vast majority of warm-blooded animals, including humans. The causative agent of toxoplasmosis, the disease, is usually minor and self-limiting but can have serious or even fatal effects on a fetus whose mother first contracts the disease during pregnancy or on an immunocompromised human or cat. Image File history File links Mergefrom. ... Tachyzoite is a stage in the growth of some microorganisms, including many responsible for parasitic diseases. ... Tachyzoites are motile form of a zoonosis. ... Bradyzoite is a stage in the growth of some microorganisms, including those responsible for many parasitic infections. ... Image File history File links Toxoplasma_gondii_tachy. ... Tachyzoite is a stage in the growth of some microorganisms, including many responsible for parasitic diseases. ... For other uses, see Scientific classification (disambiguation). ... Typical phyla Chromalveolata Chromista Heterokontophyta Haptophyta Cryptophyta (cryptomonads) Alveolata Dinoflagellata Apicomplexa Ciliophora (ciliates) Cabozoa Excavata Euglenozoa Percolozoa Metamonada Rhizaria Radiolaria Foraminifera Cercozoa Archaeplastida (in part) Rhodophyta (red algae) Glaucophyta (basal archaeplastids) Amoebozoa Choanozoa Many others; classification varies Protists (IPA: (RP); (GenAm)), Greek protiston -a meaning the (most) first of all... Classes & Subclasses Aconoidasida Haemosporasina Piroplasmasina Blastocystea Conoidasida Coccidiasina Gregarinasina The Apicomplexa are a large group of protists, characterized by the presence of a unique organelle called an apical complex. ... Orders Eucoccidiorida Conoidasida is a class of protists. ... Coccidia are microscopic, single-celled parasites that infect the intestine. ... Suborder Adeleorina Eimeriorina Eucoccidiorida is an order of microscopic, spore-forming, single-celled parasites belonging to the apicomplexan class Conoidasida. ... Sarcocystidae is a family of protozoans associated with a variety of diseases in humans and other animals. ... This article does not cite any references or sources. ... A parasite is an organism that spends a significant portion of its life in or on the living tissue of a host organism and which causes harm to the host without immediately killing it. ... Leishmania donovani, (a species of protozoan) in a bone marrow cell (in Greek proto = first and zoa = animals) are one-celled eukaryotes (that is, unicellular microbes whose cells have membrane-bound nuclei) that commonly show characteristics usually associated with animals, mobility and heterotrophy. ... For other uses, see Genus (disambiguation). ... Binomial name Felis catus Linnaeus, 1758 Synonyms Felis lybica invalid junior synonym The cat (or domestic cat, house cat) is a small carnivorous mammal. ... This article is about modern humans. ... For other uses, see Fetus (disambiguation). ... Immunosuppression is the medical suppression of the immune system. ...

Life cycle

The life cycle of T. gondii has two phases. The sexual part of the life cycle (coccidia like) takes place only in members of the Felidae family (domestic and wild cats), which makes these animals the parasite's primary host. The asexual part of the life cycle can take place in any warm-blooded animal, like other mammals (including felines) and birds. A life cycle is a period involving one generation of an organism through means of reproduction, whether through asexual reproduction or sexual reproduction. ... Sexual reproduction is a union that results in increasing genetic diversity of the offspring. ... “Feline” redirects here. ... It has been suggested that Parthenogenesis be merged into this article or section. ... Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the presence of sweat glands, including those that produce milk, and by the presence of: hair, three middle ear bones used in hearing, and a neocortex... For other uses, see Bird (disambiguation). ...

T. gondii constructing daughter scaffolds within the mother cell.

In the intermediate hosts (including felines), the parasite invades cells, forming intracellular so-called parasitophorous vacuoles containing bradyzoites, the slowly replicating form of the parasite.^[2]. Vacuoles form tissue cysts mainly within the muscles and brain. Since they are within cells, the host's immune system does not detect these cysts. Resistance to antibiotics varies, but the cysts are very difficult to eradicate entirely. Within these vacuoles T. gondii propagates by a series of binary fissions until the infected cell eventually bursts and tachyzoites are released. Tachyzoites are the motile, asexually reproducing form of the parasite. Unlike the bradyzoites, the free tachyzoites are usually efficiently cleared by the host's immune response, although some manage to infect cells and form bradyzoites, thus maintaining the infection. Image File history File links Toxoplasma_gondii. ... Image File history File links Toxoplasma_gondii. ... Schematic of typical animal cell, showing subcellular components. ... Bradyzoite is a stage in the growth of some microorganisms, including those responsible for many parasitic infections. ... A cyst (soft c, rhymes with list) is a cloed sac having a distinct membrane and division on the nearby tissue. ... A scanning electron microscope image of a single neutrophil (yellow), engulfing anthrax bacteria (orange). ... An antibiotic is a drug that kills or slows the growth of bacteria. ... Tachyzoites are motile form of a zoonosis. ...

Tissue cysts are ingested by a cat (e.g., by feeding on an infected mouse). The cysts survive passage through the stomach of the cat and the parasites infect epithelial cells of the small intestine where they undergo sexual reproduction and oocyst formation. Oocysts are shed with the feces. Animals and humans that ingest oocysts (e.g., by eating unwashed vegetables etc.) or tissue cysts in improperly cooked meat become infected. The parasite enters macrophages in the intestinal lining and is distributed via the blood stream throughout the body. In biology the small intestine is the part of the gastrointestinal tract (gut) between the stomach and the large intestine and includes the duodenum, jejunum, and ileum. ... A macrophage of a mouse stretching its arms to engulf two particles, possibly pathogens Macrophages (Greek: big eaters, from makros large + phagein eat) are cells within the tissues that originate from specific white blood cells called monocytes. ...

Acute stage toxoplasma infections can be asymptomatic, but often gives flu-like symptoms in the early acute stages, and like flu can become, in very rare cases, fatal. The acute stage fades in a few days to months, leading to the latent stage. Latent infection is normally asymptomatic; however, in the case of immunocompromised patients (such as those infected with HIV or transplant recipients on immunosuppressive therapy), toxoplasmosis can develop. The most notable manifestation of toxoplasmosis in immunocompromised patients is toxoplasmic encephalitis, which can be deadly. If infection with T. gondii occurs for the first time during pregnancy, the parasite can cross the placenta, possibly leading to hydrocephalus, intracranial calcification, and chorioretinitis, with the possibility of spontaneous abortion or intrauterine death. Influenza, commonly known as flu, is an infectious disease of birds and mammals caused by RNA viruses of the family Orthomyxoviridae (the influenza viruses). ... Species Human immunodeficiency virus 1 Human immunodeficiency virus 2 Human immunodeficiency virus (HIV) is a retrovirus that causes acquired immunodeficiency syndrome (AIDS, a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections). ... Encephalitis is an acute inflammation of the brain, commonly caused by a viral infection. ... In medicine, Chorioretinitis is an inflammation of the choroid and retina of the eye. ...

Toxoplasmosis

Main article: Toxoplasmosis

T. gondii infections have the ability to change the behavior of rats and mice, making them drawn to rather than fearful of the scent of cats. This effect is advantageous to the parasite, which will be able to sexually reproduce if its host is eaten by a cat. ^[3] The infection is almost surgical in its precision, as it does not impact a rat's other fears such as the fear of open spaces or of unfamiliar smelling food. There has been speculation that human behavior may also be affected in some ways, and correlations have been found between latent Toxoplasma infections and various characteristics such as decreased novelty-seeking behavior, slower reactions, feelings of insecurity, and neuroticism. ^[4] Species 50 species; see text *Several subfamilies of Muroids include animals called rats. ... For the band, see Neurotic (band). ...

Several independent pieces of evidence point towards a possible role of Toxoplasma infection in some cases of schizophrenia and paranoia, but this theory does not seem to account for many cases.^[5] A recent study has indicated toxoplasmosis is also correlated strongly with an increase in boy births in humans, leading to an alteration of the human sex proportion.^[6] According to the researchers, "depending on the antibody concentration, the probability of the birth of a boy can increase up to a value of 0.72 ... which means that for every 260 boys born, 100 girls are born." The study also notes a mean rate of 0.60 to 0.65 (as opposed to the normal 0.51) for Toxoplasma positive mothers. For other senses of this word, see paranoia (disambiguation). ...

References

A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

External links

• ToxoDB : The Toxoplasma gondii genome resource
• Toxoplasma images, from CDC's DPDx, in the public domain
• Toxoplasma in Live Science
• Cytoskeletal Components of an Invasion Machine—The Apical Complex of Toxoplasma gondii
• The Culture-Shaping Parasites, in Seed Magazine
• Parasite 'turns women into sex kittens' - Toxoplasma gondii allegedly makes women more attractive and men more stupid
• Toxoplasma news and researchers blog The Anti-Toxo
• Sneaky Parasite Attracts Rats to Cats, All Things Considered, April 14, 2007