Detection of Schistosoma DNA in genital specimens and urine: A comparison between five female African study populations originating from S. haematobium and/or S. mansoni endemic areas

Female Genital Schistosomiasis (FGS) is a neglected disease affecting millions, however challenging to diagnose. This explorative descriptive study compares Schistosoma real-time PCR analysis of cervico-vaginal lavages (CVL) with corresponding urine and stool samples of 933 women from five different previously described study populations. Sampling included 310 women from an S. mansoni endemic region in Mwanza, Tanzania and 112 women from a nearby S. haematobium endemic region. Findings were compared with samples collected from S. haematobium endemic regions in South Africa from 394 women and from 117 women from Madagascar of which 79 were urine pre-selected microscopy positive cases from highly-endemic communities and 38 were urine microscopy negatives from a low-endemic community. As anticipated, urine and stool microscopy and gynecological investigations varied substantially between study populations; however, the same Schistosoma real-time PCR was performed in one reference laboratory. Schistosoma DNA was detected in 13% (120/933) of the CVL, ranging from 3% in the S. mansoni Tanzanian endemic region to 61% in the pre-selected Malagasy urine microscopy positive cases. Detectable Schistosoma DNA in CVL was associated with Schistosoma DNA in urine but not with microscopic detection of eggs in urine or by cytological examination. This study confirmed real-time PCR for the detection of Schistosoma DNA in gynecological samples to be a valuable diagnostic tool to study the distribution of FGS within schistosomiasis endemic areas.