High prevalence of female genital schistosomiasis and under-detection by urine microscopy among women of reproductive age in Kilifi County, Kenya

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ABSTRACT Background Female genital schistosomiasis (FGS) is a neglected gynaecological manifestation of Schistosoma haematobium ( S. haematobium ) infection, resulting from the deposition of parasite eggs in the female genital tract. Although urogenital schistosomiasis is highly prevalent in parts of coastal Kenya, including Kilifi County, the burden of FGS among women of reproductive age remains poorly characterised. Routine diagnosis of S. haematobium infection relies largely on urine microscopy, which may underestimate genital involvement. This study aimed to assess the prevalence, diagnostic concordance, and risk factors for FGS among women of reproductive age in Kilifi County, Kenya. Methodology In this cross-sectional study, 320 randomly selected women aged 15–50 years were recruited from rural Kilifi County; 261 provided complete data for analysis. A structured questionnaire was administered to collect sociodemographic and behavioural information. Urinary schistosomiasis was assessed using triplicate urine microscopy over three consecutive days, and FGS was evaluated using real-time polymerase chain reaction (PCR) targeting the S. haematobium Dra1 gene sequence on self-collected high vaginal swabs. Results Overall, the prevalence of PCR-confirmed FGS was 36.0% (94/261), while urinary egg excretion was detected in 13.0% (34/261) of participants. Concordance between urine microscopy and genital PCR was 70.9%. Notably, 72% of women with PCR-confirmed FGS had no detectable parasite eggs in their urine. In bivariate analyses, factors such as urinary infection severity, water contact behaviours, haematuria, dysuria, age group, place of residence, and prior history of schistosomiasis were found to be associated with female genital schistosomiasis (FGS). However, in the multivariable logistic regression, only sub-location and urinary infection severity remained independently associated with the infection. Additionally, PCR cycle threshold (Ct) values showed a non-linear relationship with mean urinary egg counts, indicating that the detection of genital parasite DNA does not directly correspond to the urinary egg burden. Conclusion FGS prevalence among women in Kilifi County was substantially higher than indicated by urine microscopy alone. The majority of women with genital schistosomiasis did not exhibit detectable urinary egg excretion, highlighting the limitations of routine parasitological screening for identifying genital disease. These findings underscore the need to incorporate genital sampling and molecular diagnostics into schistosomiasis control strategies targeting women of reproductive age in endemic settings. Author’s summary Female genital schistosomiasis (FGS) is a neglected gynaecological manifestation of Schistosoma haematobium infection, occurring when parasite eggs lodge in the female genital tract. Although schistosomiasis control programmes typically rely on urine microscopy to detect infection, this approach may miss genital disease. FGS has been linked to chronic inflammation and adverse reproductive health outcomes; yet its burden among adult women in endemic areas remains poorly documented. In this study, we investigated FGS among women of reproductive age in Kilifi County, coastal Kenya, using molecular testing of self-collected genital swabs. We found that more than one-third of women had evidence of FGS. Notably, nearly three-quarters of women with genital infection had no detectable parasite eggs in their urine. This finding indicates that routine urine-based screening alone may substantially underestimate the true burden of genital schistosomiasis in endemic communities. Our results highlight a hidden burden of FGS among women of reproductive age and underscore the need to strengthen diagnostic approaches within schistosomiasis control programmes. Integrating genital sampling, improving surveillance, and reinforcing water, sanitation, and hygiene (WASH) interventions, alongside mass drug administration, could enhance early detection and reduce ongoing transmission, ultimately improving women’s reproductive health in endemic settings.

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