Congenital Toxoplasmosis: a Review of its Pathology; Immune Response and Current Treatment Options

Toxoplasmosis; caused by the protozoan parasite Toxoplasma gondii; is one of the most common parasites of man and other warm-blooded animals. Humans are infected through contaminated food; water; and blood transfusion; organ transplantation or from mother to foetus through the placenta. Severe congenital infections occur as a result of primary T. gondii infection in early pregnancy. Transmission of T.gondii to the foetus can result in serious health problems; including mental retardation; seizures; blindness and death. Frequency of foetal infection is higher when maternal infection occurs later in pregnancy and sequelae are more severe when maternal infections occur early in the first trimester of pregnancy. The ability of the parasite to survive intracellularly largely depends on the blocking of different proapoptotic signaling cascades of the host cells. During pregnancy; however; alterations in the incidence of apoptosis are associated with abnormal placental morphology and function. Both cellular and humoral immune responses control T.gondii infection. Toxoplasma is asymptomatic; infected women can only be detected by serological testing. In many instances; congenital toxoplasmosis can be prevented by educating pregnant women and women of childbearing age about the route of transmission. The need for screening suspected cases of T. gondii will help reduce transmission to the foetus

Toxoplasma serology in Zambian and Ugandan patients infected with the human immunodeficiency virus

In the USA and Europe; toxoplasmosis is well recognized as an important cause of morbidity and mortality among immunocompromised individuals. Toxoplasma gondii has been shown to be a common opportunistic infection in patients infected with the human immunodeficiency virus (HIV) in the USA and Europe with published estimates ranging from 20pc to 80pc. The importance of Toxoplasma infection in East Africa has not yet been defined. The seroprevalence rates of toxoplasmosis in Zambian and Ugandan patients were determined using the dye test (DT) and the latex agglutination test (LAT). The geographical variation in seroprevalence rates noted in western countries was also found in these African countries; with Zambia showing significantly lower rates than Uganda. 34pc of Ugandan (64/186) and 4pc of Zambian (8/187) patients infected with HIV; compared with 27pc of Ugandan (26/93) and 11pc of Zambian (20/189) HIV-negative persons; had anti-Toxoplasma immunoglobulin G antibodies. With the LAT; 13pc of the Ugandan and 7pc of the Zambian sera gave a false positive result. The relevance of Toxoplasma serology in Africa is discussed