Incidence of Toxoplasma gondii Infection in 35,940 Pregnant Women in Norway and Pregnancy Outcome for Infected Women

Abstract

From 1992 to 1994 a screening program for detection of specific Toxoplasma gondii antibodies involving 35,940 pregnant women was conducted in Norway. For women with serological evidence of primary T. gondii infection, amniocentesis and antiparasitic treatment were offered. The amniotic fluid was examined for T. gondii by PCR and mouse inoculation to detect fetal infection. Infants of infected mothers had clinical and serological follow-up for at least 1 year to detect congenital infection. Of the women 10.9% were infected before the onset of pregnancy. Forty-seven women (0.17% among previously noninfected women) showed evidence of primary infection during pregnancy. The highest incidence was detected (i) among foreign women (0.60%), (ii) in the capital city of Oslo (0.46%), and (iii) in the first trimester (0.29%). Congenital infection was detected in 11 infants, giving a transmission rate of 23% overall, 13% in the first trimester, 29% in the second, and 50% in the third. During the 1-year follow-up period only one infant, born to an untreated mother, was found to be clinically affected (unilateral chorioretinitis and loss of vision). At the beginning of pregnancy 0.6% of the previously uninfected women were falsely identified as positive by the Platelia Toxo-IgM test, the percentage increasing to 1.3% at the end of pregnancy. Of the women infected prior to pregnancy 6.8% had persisting specific immunoglobulin M (IgM). A positive specific-IgM result had a low predictive value for identifying primaryT. gondii infection.

Seroprevalence of Toxoplasma gondii in northern Greece during the last 20 years

“…The prevalence of T. gondii infection showed a significant decreasing trend in northern Greece during the study period, resulting in a high (80%) proportion of non-immune women of reproductive age. Based on an estimated incidence in 2004 of 0.51% ⁄ pregnancy, an assumed maternofetal transmission rate of 23-50% [9,20,27], and an annual birth rate of 100 000 in Greece, it can be calculated that c. 408 pregnant women are infected annually with Toxoplasma during their pregnancy, and that 90-200 children are infected in utero by T. gondii. The present results are not representative of the entire country, so further studies should be performed to establish the complete picture of Toxoplasma infection in Greece.…”

Herpes simplex virus type‐2 infection in pregnancy: no risk of fetal death: results from a nested case–control study within 35,940 women

“…The source population comprised 35,940 pregnant women in Norway. They had participated in a prospective study of Toxoplasma gondii infection in pregnancy performed by the National Institute of Public Health from June 1992 until the last delivery within the study in May 1994 12 . The source population represented almost 100% of all pregnant women in 11 of the 19 counties in Norway, approximately 60% of all pregnant women in the whole country during the study inclusion period 13 .…”

Maternal human parvovirus B19 infection and the risk of fetal death and low birthweight: a case–control study within 35 940 pregnant women

“…They participated in a prospective study on Toxoplasma gondii infection in pregnancy performed by the Norwegian Institute of Public Health from June 1992 to May 1994. 20 The serum samples from this study were stored in a biobank. The study population included almost 100% of the pregnant women in 11 of 19 counties in Norway and approximately 60% of all pregnant women in Norway during the study inclusion period.…”