Epidemiology and Infection

Ecological comparison of the risks of mother-to-child transmission and clinical manifestations of congenital toxoplasmosis according to prenatal treatment protocol

R.  GILBERT  a1 c1, D.  DUNN  a1, M.  WALLON  a2, M.  HAYDE  a3, A.  PRUSA  a3, M.  LEBECH  a4 a5, T.  KORTBEEK  a6, F.  PEYRON  a2, A.  POLLAK  a3 and E.  PETERSEN  a4
a1 Department of Epidemiology and Public Health, Institute of Child Health, London, UK
a2 Service de Parasitologie et de Pathologie Exotique, Hôpital de la Croix Rousse, Lyon, France
a3 Department of Neonatology, University Childrens' Hospital, Vienna, Austria
a4 Laboratory of Parasitology, Statens Seruminstitut, Copenhagen, Denmark
a5 Department of Gynecology-Obstetrics, University Hospital of Hvidore, Denmark
a6 Diagnostic Laboratory for Infectious Disease and Perinatal Screening (LIS), National Institute of Public Health and the Environment, Bilthoven, The Netherlands


We compared the relative risks of mother-to-child transmission of Toxoplasma gondii and clinical manifestations due to congenital toxoplasmosis associated with intensive prenatal treatment in Lyon and Austria, short term treatment in 51% of Dutch women, and no treatment in Danish women. For each cohort, relative risks were standardized for gestation at seroconversion. In total, 856 mother–child pairs were studied: 549 in Lyon, 133 in Austria, 123 in Denmark and 51 in The Netherlands. The relative risk for mother-to-child transmission compared to Lyon was 1·24 (95% CI: 0·88, 1·59) in Austria; 0·59 (0·41, 0·81) in Denmark; and 0·65 (0·37, 1·01) in The Netherlands. Relative risks for clinical manifestations compared with Lyon (adjusted for follow-up to age 3 years) were: Austria 0·19 (0·04, 0·51); Denmark 0·60 (0·13, 1·08); and The Netherlands 1·46 (0·51, 2·72). There was no clear evidence that the risk of transmission or of clinical manifestations was lowest in centres with the most intensive prenatal treatment.

(Accepted March 18 2001)

c1 Author for correspondence: Department of Paediatric Epidemiology and Biostatistics, Institute of Child Health, 30, Guilford Street, London, WC1N 1EH, UK.