Study of Toxoplasma gondii Infection in Iraqi Women Visiting Health Facilities in Al-Najaf: A Cross-sectional Study with Follow-up Serology
Zainab W. Kermasha *
Department of Laboratory Sciences, Faculty of Pharmacy, University of Kufa, Al-Najaf, Iraq.
*Author to whom correspondence should be addressed.
Abstract
Aim: This study aimed to examine the serostatus of T. gondii infection among women, estimate the prevalence of past and current infection, and assess associations with age.
Study Design: This was an epidemiological cross-sectional study conducted among 90 women.
Place and Duration of Study: The study was conducted at Al-Zahra Teaching Hospital and Al-Hakim General Hospital between January and March 2026.
Methodology: Serum samples were tested for anti-Toxoplasma IgG and IgM antibodies using an enzyme-linked fluorescent assay (ELFA), and specimens were considered positive when the IgG level was greater than 8.0 IU/mL or the IgM level was above 0.65 IU/mL. Participants were initially classified into three groups: no serologic evidence of infection, previous infection, and current infection. Paired serology was performed for the 9 IgM-positive women. Eighteen control participants were selected (nine IgG-positive and nine IgG-negative), of whom 16 completed follow-up; IgG avidity testing was performed for all IgM-positive samples.
Results: Initial classification identified 56 women (62.2%) as seronegative, 25 (27.8%) with previous infection, and 9 (10.0%) with current infection among 90 participants (median age, 27 years). Of the 9 IgM-positive women, 4 (44.4%) had acute infection, 3 (33.3%) had chronic infection with persistent IgM antibodies, and 2 (22.2%) had false-positive IgM results on paired serology. After paired testing, 4.4% (4/90) had acute infection, 31.1% (28/90) had previous/chronic infection, and 63.3% (57/90) had no serologic evidence. Overall seroprevalence, defined as previous or confirmed acute infection, was 35.6% (32/90). Seropositivity was significantly associated with age group (p = 0.041), with the highest proportion among women aged 31-40 years (60.0%).
Conclusion: A substantial proportion of participants had serological evidence of T. gondii infection. Paired serology and avidity testing reclassified more than half of the initially IgM-positive cases as chronic infection with persistent IgM or false-positive IgM results. Further studies are needed to confirm these findings.
Keywords: Toxoplasma gondii, toxoplasmosis, seroprevalence, IgG, IgM, paired serology, IgG avidity