Pm. Zadik et Ad. Siddons, LOW INCIDENCE OF PRIMARY INFECTION WITH TOXOPLASMA AMONG WOMEN IN SHEFFIELD - A SEROCONVERSION STUDY, British journal of obstetrics and gynaecology, 102(8), 1995, pp. 608-610
Objective To determine the incidence of primary toxoplasma infection i
n women of childbearing age. Design A retrospective study of seroconve
rsion on stored pairs of sera taken for routine antenatal testing. Set
ting The antenatal clinics and general practices of Sheffield between
July 1989 and October 1992. Subjects One thousand six hundred and twen
ty-one women on whom pairs of sera, separated by more than 500 days, h
ad been received. Main outcome measure Rate of primary infection deter
mined by seroconversion as measured by the presence of antibody in the
second serum and its absence in the first. Results Of 1621 women, 160
(9.9%) were initially seropositive. One seroconversion was detected i
n 2966 woman years of observation for susceptibles. The projected rate
for primary infections was 0.23 (95% CI 0.0059-1.3) per 1000 pregnanc
ies. Conclusions The rate is much lower than for earlier estimates of
incidence in the UK but agrees with a more recent estimate from Sheffi
eld and suggests a falling incidence.