Toxoplasma

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Toxoplasma

 

a genus of parasitic protozoa that has one identified species, Toxoplasma gondii. Studies of the life cycle and ultrastructure of T. gondii have shown that it belongs to the order Coccidia.

In the epithelium of the small intestines of cats and other Felidae, the parasites of Toxoplasma proceed through a complex life cycle, which is completed with the formation of minute egglike oocysts similar to those of coccidia of the genus Isospora. Each oocyst contains two spores, each of which develops into four single-celled sporozoites. The mature sporulating oocysts may reinfect felines, in which case the oocysts undergo both asexual and sexual developmental cycles. When the sporulating oocysts enter other mammals, such as mice, as well as birds and man, the oocysts undergo only asexual multiple reproduction.

After entering the macrophages and various organs and tissues, predominantly those of the reticuloendothelial, muscle, and nervous systems, the sporozoites develop into highly fecund mononuclear trophozoites (endozoites) that multiply through a type of internal budding known as endodiogeny. The trophozoites are crescent in shape and measure 4–7 micrometers in length. Their ultrastructure is identical to that of such merozoites as coccidia.

In the chronic form of toxoplasmosis, cysts are formed in a number of organs, including the brain. These cysts contain up to several hundred mononuclear organisms, called cystozoites. The endozoites and cystozoites may infest new hosts, primarily by means of the alimentary tract. Toxoplasma is the source of toxoplasmosis, a severe disease of animals and man.

IU. I. POLIANSKII

References in periodicals archive ?
The prevalence of Toxoplasma gondii oocysts in cats through Copro-PCR was significantly higher in males than females (p0.
Toxoplasmosis is caused by an intracellular protozoan parasite, Toxoplasma gondii that may result in life-long colonization in animals and humans (Ali et al.
Prevalence and Risk Factors of Toxoplasma gondii Infection in Domestic Cats from the Tropics of Mexico LTsing Serological and Molecular Tests.
Toxoplasmosis is caused by a protozoan parasite Toxoplasma gondii that affects birds and mammals through various routes (Tenter et al.
Toxoplasmosis refers to the infection caused by Toxoplasma gondii, an intracellular protozoan (Ryan and Ray, 2004; Klevar, 2007).
Se analizaron un total de 1657 mujeres embarazadas que acudieron al laboratorio regional de Salud Publica, para control de laboratorio prenatal que incluye la deteccion de anticuerpos contra Toxoplasma gondii.
Keywords: Toxoplasmosis, Toxoplasma gondii, IgM, Pregnancy outcome.
Toxoplasma gondii es un protozoario intracelular obligado de distribucion mundial, que tiene a los felinos domesticos y silvestres como hospedadores definitivos y una amplia gama de vertebrados como hospedadores intermediarios.