Regional variation in toxoplasmosis seronegativity in the São Paulo metropolitan region

Abstract

Toxoplasmosis is a highly prevalent zoonotic human infection caused by the Apicomplexa protozoon Toxoplasma gondii. The acute disease is usually mild or asymptomatic, except for foetal infection transmitted by acutely infected pregnant women, which courses as a devastating disease. In order to determine possible regional variations in risk factors, we studied the frequency of seronegativity in areas of the São Paulo Metropolitan Region, comparing titers and age groups. The prevalence of seronegativity was determined retrospectively in 1286 pregnant women receiving prenatal care at public health services in four selected areas of the São Paulo Metropolitan Region of similar socioeconomic background. The São Paulo City area had the higher frequency of seronegativity (41.1%), followed by the Northwest (31.5%) and Southwest (29.9%) areas, with similar intermediate levels, and by the Northeast (22.5%) area with the lowest frequency (p < 0.001). A rough estimate disclosed about 280 infected infants/year in the São Paulo Metropolitan Region. Serological titers analyzed by age group suggested a decline in antibody levels with age, as shown by a lower frequency of higher titers in older groups. Our study emphasizes the importance of determining the regional prevalence of toxoplasmosis for proper planning of public health prenatal care.

Santo Inácio revisited: protozoan diseases in an isolated village in northeastern Brazil after twenty years.

“…18 In Iraquara, the prevalence of both protozoan diseases was higher and similar to that found in other areas of Brazil for Chagas' diseases or toxoplasmosis. 19 Iraquara also had a low incidence of new cases of Chagas' disease, with only one young person infected. However, the long-lasting characteristic of this disease maintains its high prevalence and impairs adequate control in blood banks.…”

“…Most of the serologic data obtained in Iraquara were similar to those for other towns in Brazil. 19 This probably indicates intense human migration related to the agricultural work market, which facilitates transmission of Chagas' disease, despite the current intense vector control in the area. 20 It is interesting that specific ecologic and social conditions could maintain a low incidence of two protozoan diseases in an area for 20 years.…”

Infectivity of cysts of the ME-49 Toxoplasma gondii strain in bovine milk and homemade cheese

“…2 In Brazil, T.gondii infects around 60% of the adult population. 13 Toxoplasmosis is acquired by ingesting food and water contaminated with oocysts from feces of infected cats or by the ingestion of raw or undercooked meat, containing tissue cysts, of infected intermediary host.…”

Seroprevalence of toxoplasmosis in Fortaleza, Ceará, Brazil

“…Seropositivity in France is as high as 90%, while in the USA it is of 15% as a mean, varying from 3 to 70% according to population groups 10 . In Brazil, prevalence studies have been carried out in the southern and the Amazon region, mostly during the 70s and 80s, targeting specific populations and using different laboratory methods [12][13][14][15]19 . General seroprevalence ranged from 40 to 80%, with increasing levels according to age, low socioeconomic status, rural dwelling and raw meat cooking practices 20,21 .…”