Visual diagnosis of female genital schistosomiasis in Zambian women from hand-held colposcopy: agreement of expert image review

Abstract

Female genital schistosomiasis (FGS) can occur in S. haematobium infection and is caused by parasite egg deposition in the genital tract. Confirming a diagnosis of FGS is challenging due to the lack of a diagnostic reference standard. A 2010 expert-led consensus meeting proposed visual inspection of the cervicovaginal mucosa as an adequate reference standard for FGS diagnosis. The agreement of expert human reviewers for visual-FGS has not been previously described. Methods: In two Zambian communities, non-menstruating, non-pregnant, sexually-active women aged 18-31 years participating in the HPTN 071 (PopART) Population-Cohort were enrolled in a cross-sectional study. Self-collected genital swabs and a urine specimen were collected at a home visit; trained midwives performed CVL and hand-held colposcopy at a clinic visit. S. haematobium eggs and circulating anodic antigen (CAA) were detected from urine. Two expert reviewers independently diagnosed visual-FGS as the presence of sandy patches, rubbery papules or abnormal blood vessels in digital cervicovaginal images obtained by hand-held colposcopy. PCR-FGS was defined as Schistosoma DNA detected by real-time PCR in any genital specimen (CVL or genital swab). Results: Of 527 women with cervicovaginal colposcopic images, 468/527 (88.8%) were deemed interpretable by Reviewer 1 and 417/527 (79.1%) by Reviewer 2. Visual-FGS was detected in 35.3% (165/468) of participants by expert review of colposcopic images by Reviewer 1 and in 63.6% (265/417) by Reviewer 2. Cohen’s kappa statistic for agreement between the two expert reviewers was 0.16, corresponding to "slight" agreement. The reviewers made concordant diagnoses in 38.7% (204/527) participants (100 negative, 104 positive) and discordant diagnoses in 31.8% (168/527) participants. Conclusions: The unexpectedly low level of correlation between expert reviewers highlights the imperfect nature of visual diagnosis for FGS based on cervicovaginal images obtained with a hand-held colposcope. This finding is a call to action for improved point-of-care diagnostics for female genital schistosomiasis

Diagnosis of female genital schistosomiasis and other genital infections in young South African women: challenges in the syndromic approach

“…The currently used clinical management protocols do not include any advice to healthcare workers about FGS. Like previous studies, we found that FGS may mimic and frequently co-exists with other genital infections (20,24). We found FGS to be as prevalent as other well-known genital diseases in our relatively large study from rural South Africa, and there is reason to believe that this could hold true in many regions of Sub-Saharan Africa (8, 24, 30, 31).…”

“…If a woman presents with vaginal discharge at a low-resource primary healthcare clinic, the current guidelines recommend giving her ceftriaxone, azithromycin, and metronidazole to treat three diseases simultaneously, namely, gonorrhea, chlamydia, and trichomoniasis (14, 19). However, in areas endemic for S. haematobium, these symptoms may be caused by FGS (20,21). Therefore, women are at risk of not receiving the appropriate treatment as per the current management protocols.…”

The Prevalence of Female Genital Bilharziasis (FGB) in the Northern Region of Senegal

“…The northern region of Senegal is marked by a high endemicity of bilharzia. In Zambia, A. Sturt [7] found a 38.5% frequency of FBG lesions in colposcopic examinations.…”

The Zipime-Weka-Schista study protocol: a longitudinal cohort study and economic evaluation of an integrated home-based approach for genital multi-pathogen screening in women, including female genital schistosomiasis, HPV, Trichomonas and HIV in Zambia

“…Hand-held colposcopy as a low-cost device has been used in both cervical cancer screening and FGS studies 4 66 . However, expert review is still required for the identification of characteristic FGS lesions and inter-rater correlation is poor 67 . In addition, in this study, testing for the DNA detection of different pathogens will be performed with conventional molecular assays that are field deployable 32 40 .…”