[Toxoplasma gondii serology in pregnant woman: characteristics and pitfalls]. / Sérologie de la toxoplasmose chez la femme enceinte : caractéristiques et pièges.

Screening program of congenital toxoplasmosis depends principally on serological testing and follow-up of pregnant women with negative serology from the onset of pregnancy. This program is particularly efficient because the majority of cases of obstetrical seroconversion are diagnosed and followed up. Serological techniques have evolved with time and are many on the market. The "IgG" tests are more and more specific at the detriment of their sensitivity. The latter is variable from one technique to the other. In 2008, despite the presence of an international standard, serological titrations are particularly variable making interpretation of the kinetics impossible between two different series, two techniques or two laboratories. In cases of interpretation discordance or borderline values, it is useful to do a confirmatory technique. The dye test or the western blot are useful in these cases and prevent up to 2 to 8% of unnecessary obstetric follow up. IgM tests are becoming more and more sensitive and precocious. These tests frequently detect "non specific IgM" as well as "residual IgM" (associated with a stable positive IgG titre). In such cases and in the absence of a preceding positive result, a complementary test done by specialized laboratories (such as ISAgA IgM or IgA, IgG avidity test, differential agglutination, etc.) is indispensable in order to prevent any error of interpretation. These complementary tests as well as the serological evolution (control done in 15 days) permit, in a large number of cases, to reassure the patient with full confidence.

Seroprevalence of T. gondii in sheep from Marrakech, Morocco.

Toxoplasma gondii is a ubiquitous intracellular protozoan parasite transmitted by food. Concerning this parasite, there are few studies done in Morocco. In this study, 261 sera from sheep intended for consumption in Marrakech were subjected to the Toxoplasma ELISA based serology test for the detection of anti-T. gondii specific IgG confirming a past infection. Of the total tested 72 (27.6%) sera were positive for IgG. This result shows that the seroprevalence approaches the world average and is similar to what is found in other cities of Morocco. This has prompted us to investigate other animal species in the region in order to evaluate the degree of contamination by this parasite as well as the potential risk incurred on consumption of their meat.