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 ?
Wild and domestic cats are the only known hosts of Toxoplasma, in which the parasite forms egglike stages, called oocysts, in their faeces.
We thank Tokio Hoshina for detecting Toxoplasma nucleic acid by LAMP.
Se utilizo el <<kit>> comercial PrioCHECK Porcine Toxoplasma Ab (Prionics Ag, Suiza), siguiendo las instrucciones de acuerdo con el protocolo del fabricante.
Overall 419 serum samples were tested against anti- Toxoplasma, anti- Rubella, anti HSV and anti-CMV IgM antibodies by EL ISA.
Depending on the location and severity of toxoplasma chorioretinitis, infection can result in permanent retinal scarring and loss of visual acuity.
The prevalence of Toxoplasma gondii oocysts in cats through Copro-PCR was significantly higher in males than females (p0.05).
In 96-well microtitre plates, 5x1[0.sup.5] per well were cultured in RPMI 1640 (Gibco) and 10% FCS (Gibco) and allowed to multiply for 72 hr in the medium alone (control group), in the presence of 40 [mu]g/ml of Toxoplasma Lysate Antigen (TLA) and incubated at 37 [degrees]C and 5% C[O.sub.2].
We used a Toxoplasma gondii rabbit polyclonal antibody manufactured by Cell Marque (ref.
In the chronic group, infection was documented by the measurement of IgG antibodies to Toxoplasma whole cell organism following the manufacture's protocol (Vir-ELISA Anti-Toxo kit, VIRO-Immun Labor-Diagnostika GmbH, Germany, EG 127) (Table S2).
Toxoplasmosis is caused by coccidian parasite, Toxoplasma gondii.