Toxoplasmosis is caused by the protozoan parasite Toxoplasmosis Gondii.  It is transmitted to humans via cat feces in contaminated soil or litter trays, and by ingestion of raw or lightly cooked infected meat.  About 50% of the world’s population has been infected. Most infections pass unnoticed or result in flu-like symptoms, and cause no problems in healthy individuals, except in cases where the infecting dose is exceptionally high, sometimes leading to chorioretinitis. Toxoplasmosis can be very dangerous in immune-compromised patients.

The main public health problem posed by toxoplasmosis is to pregnant women. If a primary infection occurs during pregnancy, the fetus is at risk of congenital toxoplasmosis, which can lead to severe neurological problems. In France women are tested in pregnancy, and if seronegative they are retested every month until delivery. Similar but less intense testing is carried out in Austria and parts of Italy and Switzerland. Women who are found to have a primary infection during pregnancy can be offered a termination or treatment with anti-parasitic drugs.

The objective of this study was to estimate the incidence of primary toxoplasmosis in pregnant women, to inform decisions about whether screening during pregnancy should be introduced in the UK.

The synthesis incorporated several kinds of study: age- and time-specific sero-prevalence, studies of incidence based on sero-conversion, studies of the prevalence Toxoplasma-specific IgM antibody, which reflects resent infection, and data on the duration of the IgM antibody response.

Welton NJ, Ades AE. A model of toxoplasmosis incidence in the UK: evidence synthesis and consistency of evidence.  Journal of the Royal Statistical Society: Series C (Applied Statistics) 2005; 54(2), 385–404.    DOI: 10.1111/j.1467-9876.2005.00490.x 
http://onlinelibrary.wiley.com/doi/10.1111/j.1467-9876.2005.00490.x/pdf