Absence of lower genital tract lesions among women of reproductive age infected with Schistosoma mansoni: A cross-sectional study using a colposcope in Western Kenya.

Schistosomiasis is endemic in sub-Saharan Africa where close to 205 million people are infected and many more are at risk of infection [ 1 ]. The most vulnerable are children and women who frequently come into contact with snail-infested water while playing, or in the course of their daily chores [ 2 ]. Despite current treatment efforts with mass drug administration using praziquantel, re-infections and chronic infection occur leading to morbidity that may last for decades, including Female Genital Schistosomiasis (FGS) [ 3 – 5 ]. All the human Schistosoma species may deposit ova in the genitals, sometimes denoted “ectopic schistosomiasis”. S . mansoni ova, usually located in the lower gastrointestinal tract, are sometimes also found as far as the urinary tract and it is hypothesized that ova travel from the intestinal tract to the genital organs through blood vessel anastomoses in the pelvis [ 6 , 7 ]. However, lower genital tract lesions have almost exclusively been reported from S . haematobium infected women [ 8 – 14 ]. FGS affects an estimated 56 million women worldwide [ 15 ]. Kenya is endemic for both the intestinal form (caused by S . mansoni ) and the urogenital form (caused by S . haematobium ) of schistosomiasis, with an estimate of approximately 9 million people infected and approximately 17.4 million at risk [ 16 ]. S . haematobium infection manifests itself with bloody urine, pain on urination, and higher risk of bladder cancer, genital symptoms and lesions [ 13 , 17 ]. The lower genital tract manifestations in women are grainy sandy patches, homogenous yellow patches, rubbery papules, abnormal blood vessels and mucosal bleeding of the surfaces, both in the vagina wall and on the cervix [ 18 ]. FGS is associated with decreased fertility, ectopic pregnancies, abdomino-pelvic pain, genital itch, dyspareunia, foul smelling discharge, and has been found to be associated with HIV [ 19 – 23 ]. There are a number of case reports of S . mansoni ova in the genital tract and it has been hypothesized that it could lead to similar lower genital tract morbidity [ 24 – 26 ]. However, only a paucity of studies have explored this. A study in Brazil, where only S . mansoni is endemic, found no genital tract morbidity due to schistosomiasis [ 27 ], but S . mansoni infection intensity was low and participants had received repeated praziquantel treatment. A second study by Downs and others in an area endemic for both S . haematobium and S . mansoni in Tanzania reported that 5% of the women had Schistosoma ova in cytology smears, but the authors did not differentiate the cases according to Schistosoma species and genitalia were not inspected for lesions [ 28 ]. Interestingly, the prevalence of HIV was higher in the S . mansoni villages than in the S . haematobium villages [ 28 ]. A qualitative study in western Kenya found that genital health problems were reported among women exposed to S . mansoni , but no diagnostic tests were done and there was no control group [ 29 ]. Cunin et al found that people with very high infection intensity of dual infection with S . mansoni and S. haematobium made it more likely to find S . mansoni ova in urine, possibly as a result of “worm over-crowding” [ 7 ]. HIV/AIDS is a leading cause of death in Kenya and is disproportionately high in Nyanza, western Kenya along the shores of Lake Victoria [ 30 , 31 ], an area that also has a high prevalence of S . mansoni [ 32 – 35 ]. Based on these observations and the hypothesis that S . mansoni may also be a risk factor for HIV [ 28 ], we sought to explore the prevalence of FGS in a S . mansoni -endemic area, investigate if S . mansoni causes lesions in the lower genital tract, and characterize the gynaecological symptoms in women with S . mansoni infection.

Out of the 773 women who provided stool samples, 414 (53.6%) had S . mansoni infection with a mean intensity of 185 epg (95%CI: 155–216 epg). A total of 72 women from Kisumu West and 79 from Rachuonyo North sub-counties came for gynaecological investigations. We included 147 women as 2 had recently delivered a baby and 2 had undergone hysterectomies. The mean age of menarche was 14 years (SD = 1.96). Among the 147 women who underwent gynaecological examinations, the mean intensity of S . mansoni infection was 253 epg (95% CI: 195–312 epg). Table 1 shows that almost all these women had contact with Lake Victoria waters at least once per day, more than 90% lived less than 900 metres from the lake, and most used the lake as their main water source for domestic chores. Table 2 shows that more than half of the included population had heavy or moderate infections. The prevalence of the soil-transmitted helminths was 4.5% (95%CI: 3.3–6.3) for T . trichiura , 2.2% (95%CI: 1.4–3.5) for A . lumbricoides , and 0.3% (95%CI: 0.01–1) for hookworm respectively. No S . mansoni eggs were detected in the urine of any of the participants. None of the women had Schistosoma ova in their Pap smears. a 95% Confidence Interval. b Arithmetic mean infection intensity of eggs found in stool. c All included for gynae examination were S . mansoni positive Homogenous yellow patches were found in 12/147 (8.2%) of the study population. No participants were found to have grainy sandy patches or rubbery papules. The women with homogenous yellow patches were significantly older than the remaining population (OR 1.1, 95% CI: 1.0–1.2, p = 0.001), mean age 47 years (SD 11.2) versus 34 years (SD 10.7). Homogenous yellow patches were not associated with the intensity of S . mansoni infection (age-Adjusted Odds Ratio (AOR) 0.6, 95% CI: 0.1–6.7, p = 0.70) ( Fig 3 ). Likewise, having abnormal blood vessels on the mucosal surface (49/147, 33%), was not associated with the intensity of S . mansoni infection (AOR 1.0, 95% CI: 1.0–1.0, p = 0.14). In 7 of the 147 women (4.8%), not all the surfaces of the fornices could be seen. No significant association between symptoms and intensity of S . mansoni . *Likelihood ratio p-value. More than half of the population had genital symptoms (58%). S . mansoni intensity was not associated with higher prevalence of abnormal vaginal discharge (AOR 0.8, 95% CI: 0.1–6.7, p = 0.81), bloody discharge (AOR 0.2, 95% CI: 0.1–0.8, p = 0.21), or genital itch (AOR 0.8, 95% CI: 0.2–3.2, p = 0.79), as shown in Fig 3 . Homogenous yellow patches (n = 12) were not associated with any of the symptoms (p >0.39). In a selection of 140 women who were fully investigated gynecologically (all surfaces seen), 16 (11.4%) said they had grown up “far away” from Lake Victoria, although the exact distance could not be determined. They also indicated that they used other water sources in their childhood, such as rivers. These women had significantly more homogenous yellow patches (OR 5.6, 95% CI 1.4–21.8, p = 0.014). The age-adjusted odds ratio (AOR) was 3.9 (95% CI: 0.92–16.9, p = 0.065). Childhood residence or river contact did not influence the presence of abnormal blood vessels (p > 0.8).

In this study population we found that S . mansoni was not associated with lower genital tract lesions or genital symptoms. However, further investigations are needed to explore the causes of genital symptoms around Lake Victoria to offer correct management. Furthermore, the possibility of lesions and pathology due to S . mansoni in the upper genital tract should be explored.

Approval for the study was obtained from the Kenya Medical Research Institute (KEMRI) Scientific Steering Committees as well as the KEMRI National Ethical Review Committee (KEMRI SSC # 2937). Consent documents and participation information were approved and provided to potential study participants in English or the local language, Dholuo. The local authorities and health professionals were informed about the study. Informed written consent was obtained from each participant. A unique coded identification number was assigned to each subject and was used for sample tracking. All identifiers were delinked from data for the analysis. Privacy and confidentiality were strictly maintained. The risks of the study were minimal, with only the temporary discomfort and brief embarrassment associated with the gynaecological examination. All participants were treated with 40 mg/kg praziquantel (PZQ) and those infected with soil-transmitted helminths (STHs) were treated with 400 mg albendazole. In addition, treatment was provided in accordance with the Kenyan syndromic management protocol for sexually transmitted infections (STI). Results and treatment were delivered privately to the participant by a local professional nurse immediately after the study procedures. The study was conducted in Rachuonyo North and Kisumu West sub-counties ( Fig 1 ), western Kenya in November 2015. The area is characterized by a modified equatorial climate. It is generally warm and humid with the long rains falling from March to May and the short rains between August and November/December, with an average annual temperature of 25°C. In this study, we focused on villages that are within a 5 km distance from Lake Victoria, where S . mansoni prevalence is the highest [ 36 ]. Together with other sub-counties bordering the lake, the region has the highest prevalence of HIV/AIDS (15.1%) in Kenya amongst persons aged 15–64 years [ 30 ]. The exact HIV prevalence in the selected communities was not known, however the overall prevalence of HIV in Kisumu was 16.3% [ 37 ]. The chief mode of HIV transmission is thought to be via heterosexual intercourse [ 38 , 39 ]. (A) Kisumu West and (B) Rachuonyo North sub-counties, https://opensource.com/ . The majority of the population consisted of the Luo ethnic community who were at risk of infection with S . mansoni through their occupational or recreational activities. This cross-sectional study focused on 18–50 year old women. At the time of the study, mass drug administration for schistosomiasis control was unavailable for adults in this endemic area. Women were approached at home by a community health worker to introduce the study and invite potential participants on a specific date to a specified health facility in their community. The investigators held information meetings and sought consent. Women who were not observably ill, were willing to take part in the study, and to provide the requested samples (stool, urine, blood, and intra-vaginal examination) were invited to participate. Only women who were S . mansoni egg-positive and S . haematobium egg-negative were invited for gynaecological examination. Fig 2 provides an overview of the participant recruitment process. a Males, children, outside age range. b Cervix, fornices, lateral, anterior and/or posterior vaginal walls. Stool and urine samples from three consecutive days were collected at the health facility, transported to the KEMRI laboratory and investigated microscopically for S . mansoni and S . haematobium eggs. Two Kato-Katz smears were prepared from each stool sample and read by trained microscopists. Eggs were enumerated to determine eggs per gram of faeces (epg) and the presence or absence of the STHs ( Ascaris lumbricoides , Trichuris trichiura , hookworm) was noted. Intensity of infection for schistosomiasis was calculated based on arithmetic mean egg counts and categorized according to the WHO classification as negative for no detectable eggs; light S . mansoni infection for 1–99 epg; moderate for 100–399 epg and ≥400 epg for heavy [ 40 ]. Urine samples were thoroughly mixed and a 10 ml aliquot of urine filtered through 12 micrometres, 13 millimetres Polycarbonate (PCTE) membrane filters (Sterlitech; Kent, WA). The filter paper was then placed on a labelled slide and a drop of Lugol’s solution added. The slides were then examined under a microscope for S . haematobium and S . mansoni eggs [ 40 ]. A questionnaire on water contact behaviour, reproductive history, water sources, water exposure, genital and abdominal symptoms was administered individually to S . mansoni egg-positive/ S . haematobium egg-negative participants in the local language (Dholuo) prior to gynaecological examination. The clinician performing the exams was blinded to the childhood origin of the women and the intensity of S . mansoni infection. Examination was commenced by cervico-vaginal lavage. Saline (10 ml) was sprayed on the vaginal wall and cervix twice, whereupon it was drawn back into a syringe and deposited into four tubes. This was followed by photocolposcopic examination (Leisegang Photocolposcope, Germany, Magnifications 7.5; 15; 30) using an autoclaved metal speculum after which Pap (Papanicolau) smears were collected from all consenting women [ 41 ]. The cervix, the fornices, the entire vaginal wall and vulval surfaces were inspected section by section according to a predefined protocol [ 41 ]. Acetic acid and/or iodine application for colposcopic examination was always done last. The grainy sandy patch diagnosis was defined as observing grains approximately 0.05 mm by 0.2 mm long, shaped as minuscule rice grains, appearing singly or in clusters of up to 300 grains [ 42 ]. The homogeneous yellow patches were defined as sandy looking areas with no visible grains when using the x15 magnification setting on the colposcope. Rubbery papules were defined as papulous lesions, firm as hard rubber, that had only been seen in Madagascan women by the same clinician who had previously investigated women for FGS in four Southern African countries [ 43 ]. Abnormal blood vessels were defined as pathological convoluted (cork-screw), reticular, circular and/ or branched, uneven-calibre blood vessels visible (by x15 magnification) on the mucosal surface. Contact bleeding was defined as fresh blood originating from the mucosal surface. Pre-contact bleeding was defined as darkened blood on the mucosal surface in the absence of recent or present menstruation. A polyp was defined as a single, smooth pedunculated mass originating from the endocervix or from the mucosal surface. Leucoplakia was defined as white plaque on the mucosal surface, visible with or without acetic acid. Papilloma was defined as a sessile mass either on the mucosa or vulva, whitish in colour, often with a cauliflower appearance. Data were entered into Excel, and analysed using SPSS version 12 and Graphpad Prism 5. Prevalence of S . mansoni and soil-transmitted helminths are presented for all who underwent gynaecological examination. S . mansoni data is also presented for those who submitted stool but did not attend the research clinic. Univariate and multivariate analyses were used to determine associations between the clinical manifestations and the intensity of S . mansoni infection. P values < 0.05 were considered statistically significant.

(XLSX) Click here for additional data file.