Anabela Vilares

Seroepidemiology of Toxoplasma gondii infection in women from the North of Portugal in their childbearing years.

Seroprevalence of Toxoplasma gondii infection and associated risk factors were investigated in 401 women of childbearing age from the North of Portugal. Of the 98 (24·4%) seropositive women, 92 (93·9%) only had immunoglobulin (Ig)G, two (2·0%) only had IgM, and four (4·1%) others had both IgG and IgM. Risk factors for T. gondii infection in women were: engaging in soil-related activities without gloves [odds ratio (OR) 8·4], consumption of unwashed raw vegetables or fruit (OR 7·6), and consumption of smoked or cured (non-cooked) processed pork products (OR 2·5). Most women of childbearing age from the North Portugal are susceptible to primary infection with T. gondii and, therefore, the risk of congenital toxoplasmosis remains high.

Isolation and molecular characterization of Toxoplasma gondii isolated from pigeons and stray cats in Lisbon, Portugal

Cats and pigeons are important factors in the epidemiology of Toxoplasma gondii as felids are the only definitive hosts that can excrete environmentally resistant oocysts, and pigeons share the same places of cats and humans constituting a good model and indicator of the ground field contamination. We aimed to study the virulence and genotypes of T. gondii isolated from pigeons and stray cats in Lisbon, Portugal. Fresh samples of brain from 41 pigeons and 164 cats revealing antibodies to T. gondii were inoculated in mice. Three isolates (one isolated from a cat and two isolated from pigeons) were virulent in the mouse model. Sag2-based genotyping of T. gondii was achieved in 70.7% (29/41) of samples isolated from pigeons (26 samples were type II, two were type III, and one strain was type I). From the cat brain samples, 50% (82/164) yielded Sag2 positive results, where 72 belonged to genotype II and 10 were no type III (it was not possible to discriminate between type I and II). Further genotyping was obtained by multiplex PCR of 5 microsatellites (TUB2, TgM-A, W35, B17, B18), allowing the identification of two recombinant strains that had been previously identified as type II by Sag2 amplification (one isolated from cat brain and the other from pigeon brain). This is the first evidence of recombinant strains circulating in Portugal and the first report of T. gondii genotyping from cats in this country. This study also highlights the importance of environmental contamination in the synanthropic cycle constituting a potential source of human infection.

Toxoplasma gondii seroprevalence in the Portuguese population: comparison of three cross-sectional studies spanning three decades

Background Toxoplasma gondii is an obligate intracellular protozoan infecting up to one-third of the worlds population, constituting a life threat if transmitted from mother to child during pregnancy. In Portugal, there is a lack of knowledge of the current epidemiological situation, as the unique toxoplasmosis National Serological Survey was performed in 1979/1980. Methods We studied the seroprevalence trends in the Portuguese general population over the past 3 decades, by assessing chronological spread cross-sectional studies, with special focus on women of childbearing age, by age group, region and gender. Results The T. gondii overall seroprevalence decreased from 47% in 1979/1980 to 22% (95% CI 20% to 24%) in 2013. Generally, we observed that the prevalence of T. gondii IgG increased significantly with age and it decreased over time, both in the general population and in the childbearing women (18% prevalence in 2013). Conclusions The scenario observed for the latter indicates that more than 80% of childbearing women are susceptible to primary infection yielding a risk of congenital toxoplasmosis and respective sequelae. Since there is no vaccine to prevent human toxoplasmosis, the improvement of primary prevention constitutes a major tool to avoid infection in such susceptible groups.