Oocysts Toxoplasma

Dumetre, A. and Darde, M. L. (2003). Flow to detect Toxoplasma gondii oocysts in environmental samples . FEMS Microbiol. Rev. 27, 651-661. 

One of the most common infections in man is caused by the protozoan, Toxoplasma gondii, which is transmitted to humans when they consume raw or inadequately cooked, infected meat. Infected pregnant women can transmit the organism to the fetus. Cats are the only animals that shed oocysts that can infect other animals as well as man. The treatment of choice for this condition is the antifolate drug, pyrimethamine [peer i METH a meen] (see p. 353). A combination of sulfadiazine (see p. 289) and pyrimethamine is also efficacious. Leucovorin is often administered to protect against folate deficiency. Other inhibitors of folate biosynthesis, such as trimethoprim (see p. 293) and sulfamethoxazole (see p. 289) are without therapeutic efficacy in toxoplasmosis. [Note At the first appearance of a rash, pyrimethamine should be discontinued since hypersensitivity to this drug can be severe.]... 

Arkush, K.D., Miller, M.A., Leutenegger, C.M., Gardner, I.A., Packham, A.E., Heckeroth, A.R.Tenter, A.M., Barr, B.C., and Conrad, P.A. 2003. Molecular and bioassay-based detection of Toxoplasma gondii oocyst uptake by mussels (Mytilus galloprovincialis). Inti. J. Parasitol. 33,1087-1097. Azevedo, C. 1989. Ultrastructure observations of Cryptosporidium sp. parasite of Ruditapes decussatus (Mollusca, Bivalvia). J. Inverteb. Pathol. 54, 23-27. 

Lindsay, D.S., Phelps, K.K., Smith, S.A., Flick, G., Summer, S.S., and Dubey, J.P. 2001. Removal of Toxoplasma gondii oocysts from sea water by eastern oysters Crassostrea virginica). J. Eukaryot. Microbiol. Suppl, 197S-198S. 

On the whole, which are the infectious forms of foodbome parasites Main infectious stages (to humans) of coccidian parasites are either highly resistant oocysts (monoxenous species), like Cryptosporidium, or tissue zoites (heteroxenous species), contained in tissue cysts, like those of Toxoplasma. Other parasitic Protozoa develop resistant cystic forms in their life cycle, like Giardia. 

Lecointre G, Le Guyader H (2001) Qassification phylogenetique du vivant. BeUn, Paris Li X, Guyot K, Dei-Cas E, Mallard IP, Ballet 11, Brasseur P (2006) Cryptosporidium oocysts in mussels Mytilus edulis) from Normandy (Prance). Int 1 Pood Microbiol 108 321-325 Lindsay DS, Collins MV, Mitchell SM, Welch CN, Rosypal AC, Phck GJ, Zajac AM, Lindquist A, Dubey IP (2004) Survival of Toxoplasma gondii oocysts in Eastern oysters Crassostrea virginica). 1 Parasitol 90 1054—1057... 

Dubey, J. P. (1998a). Toxoplasma gondii oocysts survival under defined temperatures. /. Parasitol. 84, 862-865. 

Frenkel, J. K., Dubey, J. P., and Miller, N. L. (1970). Toxoplasma gondii in cats Fecal stages identified as coccidian oocysts. Science 167, 893-896. 

A low catalase activity has been found in sporulated oocysts and in sporozoites of Eimeria tenella (34) but its location was not determined. Only low levels of catalase were found in P. berghei, probably as a result of contamination of the preparations with host cell material (35). Toxoplasma gondii tachyzoites have an abundant catalase activity (36). 

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