Keywords
molecular diagnosis
toxoplasmosis
female livestock farmers
cataractes district
Democratic Republic of the Congo
How to Cite
Abstract
Introduction
Toxoplasmosis represents a major public health concern due to its significant contribution to neonatal morbidity, mortality, and congenital complications. Diagnostic algorithms routinely rely on the detection of anti-Toxoplasma gondii antibodies (IgM/IgG) and molecular techniques, such as polymerase chain reaction (PCR).
Purpose
To evaluate and compare the performance of serological and molecular diagnostic methods for detecting Toxoplasma gondii infection among female livestock farmers in the Cataractes District, Kongo Central Province, Democratic Republic of the Congo.
Methods
An analytical cross-sectional study was conducted between November 2023 and February 2024 among 398 female pig farmers aged ≥ 18 years residing in the Cataractes District. Serological screening was performed by measuring anti-T. gondii IgM antibodies via the VIDAS Enzyme-Linked Fluorescent Assay (ELFA). Genomic DNA was extracted using the QIAGEN DNA extraction kit, and conventional PCR was conducted targeting the T. gondii B1 gene. PCR was utilized as the reference standard. Statistical analysis was performed using R software (version 4.3.2).
Results
Among the 398 participants, 63 (15.83%) were positive for anti-T. gondii IgM antibodies, and 74 (18.59%) tested positive by PCR. Mbanza-Ngungu Territory demonstrated high positivity, with 22 (5.53%) IgM-positive and 25 (6.28%) PCR-positive participants. Cross-tabulation revealed 56 true positives, 317 true negatives, 7 false positives (1.76%), and 18 false negatives (4.52%). A highly significant association was observed between IgM serology and PCR (χ² = 238.87, df = 1, p < .001; Fisher's exact test p < .001; Odds Ratio [OR] = 135.61, 95% CI [52.81, 348.12]). Using PCR as the reference standard, IgM serology exhibited a sensitivity of 75.68% (95% CI [64.79, 84.02]), specificity of 97.84% (95% CI [95.61, 98.95]), overall accuracy of 93.72% (95% CI [90.89, 95.71]), positive predictive value (PPV) of 88.89% (95% CI [78.80, 94.51]), negative predictive value (NPV) of 94.63% (95% CI [91.67, 96.57]), and a Cohen's kappa coefficient (κ) of 0.7799.
Conclusion
Serological and molecular assays show strong diagnostic concordance and should be deployed as complementary tools for evaluating toxoplasmosis in occupationally exposed populations. Incorporating molecular screening into routine epidemiological surveillance will enhance early detection and targeted intervention strategies.
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