Toxoplasma

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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

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

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
High frequency of toxoplasma antibodies in sera of women with a single abortion can be interpreted by the fact that there were more women who participated in the study at a young age, so their immunity against infectious agents was not as strong as the older ages to fight against toxoplasma.
(27) Hypo-gamma-globulinemia in the study group refers to a diminished immune system to produce sufficient antibodies, especially toxoplasma IgG, to prevent reactivation sequels that are obviously seen among women with toxoplasmosis by spontaneous or recurrent abortion.
Main causes of sero-conversion of toxoplasma antibodies are mostly due to parasite challenges against a host immune system such as antigenic coat changing.
From the results, it can be concluded that the prevalence of toxoplasma antibodies among young age women in Kirkuk province is high especially in urban areas, in non-pregnant women, and during autumn.
Sher, "Effector cells of both nonhemopoietic and hemopoietic origin are required for interferon (IFN)-[gamma]- and tumor necrosis factor (TNF)-[alpha]- dependent host resistance to the intracellular pathogen, Toxoplasma gondii," Journal of Experimental Medicine, vol.
Weiss, "Effect of cytokines on growth of Toxoplasma gondii in murine astrocytes," Infection and Immunity, vol.
Zerrahn et al., "The IFN-[gamma]-inducible GTPase, irga6, protects mice against Toxoplasma gondii but not against Plasmodium berghei and some other intracellular pathogens," PLoS ONE, vol.
Zerrahn et al., "Disruption of Toxoplasma gondii parasitophorous vacuoles by the mouse p47-resistance GTPases," PLoS Pathogens, vol.
Comparison of PCR detection methods for B1, P30, and 18S rDNA genes of Toxoplasma gondii in aqueous humor.
Comparison between two Real-time PCR assays and a nested-PCR for the detection of Toxoplasma gondii.
PCR detection of Toxoplasma gondii DNA in CSF for the differential diagnosis of AIDS-related focal brain lesions.
Rapid and sensitive diagnosis of Toxoplasma gondii infections by PCR.