Case-Control Study of Posttreatment Regression of Urinary Tract Morbidity Among Adults in Schistosoma haematobium-Endemic Communities in Kwale County, Kenya

A 14-year follow-up of ultrasound-detected urinary tract pathology associated with urogenital schistosomiasis in women living in the Msambweni region of coastal Kenya

BACKGROUND

Complications of urogenital schistosomiasis include acute inflammatory and chronic fibrotic changes within the urogenital tract. Disease burden of this neglected tropical disease is often underestimated, as only active, urine egg-patent Schistosoma infection is formally considered. Previous studies have focussed on short-term effects of praziquantel treatment on urinary tract pathology, demonstrating that acute inflammation is reversible. However, the reversibility of chronic changes is less well studied.

METHODS

Our study compared, at two time points 14 y apart, urine egg-patent infection and urinary tract pathology in a cohort of women living in a highly endemic area having intermittent praziquantel treatment(s). In 2014 we matched 93 women to their findings in a previous study in 2000.

RESULTS

Between 2000 and 2014 the rate of egg-patent infection decreased from 34% (95% confidence interval [CI] 25 to 44) to 9% (95% CI 3 to 14). However, urinary tract pathology increased from 15% (95% CI 8 to 22) to 19% (95% CI 11 to 27), with the greatest increase seen in bladder thickening and shape abnormality.

CONCLUSIONS

Despite praziquantel treatment, fibrosis from chronic schistosomiasis outlasts the presence of active infection, continuing to cause lasting morbidity. We suggest that future efforts to eliminate persistent morbidity attributable to schistosomiasis should include intensified disease management.

Schistosomiasis, soil transmitted helminthiasis, and malaria co-infections among women of reproductive age in rural communities of Kwale County, coastal Kenya

Background

Schistosoma haematobium, soil transmitted helminthes (STH), and malaria lead to a double burden in pregnancy that eventually leads to poor immunity, increased susceptibility to other infections, and poor pregnancy outcomes. Many studies have been carried out on pre-school and school aged children but very little has been done among the at risk adult population including women of reproductive age (WRA). Our current study sought to establish the risk factors and burden of co-infection with S. haematobium, STH, and Plasmodium sp. among WRA in Kwale County, Coastal Kenya.

Methods

A total of 534 WRA between the ages of 15–50 were enrolled in this cross-sectional study from four villages; Bilashaka and Mwaluphamba in Matuga sub-County, and Mwachinga and Dumbule in Kinango sub-County. Socio-demographic information was collected using a pre-tested standardized questionnaire. Parasitological examination was done using urine filtration method for Schistosoma haematobium, Kato Katz for STH (Ascaris lumbricoides, Hookworm, Trichuris trichiura), and standard slide microscopy for Plasmodium sp. Statistical analyses were carried out using STATA version 15.1.

Results

The overall prevalence of S. haematobium was 3.8% (95% CI: 2.6–5.4) while that for malaria was 4.9% (95% CI: 2.0–11.7). The prevalence of STH was 5.6% (95% CI: 2.8–11.3) with overall prevalence of 5.3% (95% CI: 2.5–10.9) for hookworm and 0.6% (95% CI: 0.2–1.9) for T. trichiura. The occurrence of co-infection was low and was recorded between S. haematobium and P. falciparum (0.6%), followed by S. haematobium and STH (0.4%).

Among pregnant women, 2.6% had co-infection with S. haematobium and P. falciparum. Only 1.3% had co-infection with S. haematobium and hookworm or T. trichiura. Among non-pregnant women, co-infection with S. haematobium and P. falciparum was 0.2%. Similarly, co-infection with S. haematobium and hookworm or T. trichiura was 0.2%.

Bed net ownership and usage among pregnant women was 87.8 and 96.6%, respectively. 66.3% of the women reported using improved water sources for drinking while 78.1% reported using improved sanitation facilities.

Conclusion

The use of improved WASH activities might have contributed to the low prevalence of STHs and S. haematobium infections. Further, bed net ownership and usage might have resulted in the low prevalence of Plasmodium sp. infections observed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12526-0.

Usefulness of ultrasound in sub-Saharan patients with a serological diagnosis of schistosomiasis

OBJECTIVE

To evaluate the usefulness of ultrasound examination in patients with just a serological diagnosis of schistosomiasis but no other evidence of active infection.

METHODS

346 sub-Saharan patients with possible schistosomiasis that presented at a Tropical Medicine Unit between 2008 and 2019 were retrospectively selected. Possible schistosomiasis was considered in those patients with a positive serology for schistosomasis in the absence of direct microbiological isolates, hematuria and/or eosinophilia. Data from ultrasound examinations before and after treatment with praziquantel were collected and categorized following the World Health Organization-Niamey score to standardize the use of ultrasonography for the assessment of schistosomiasis-related morbidity.

RESULTS

Ultrasound examinations were abnormal in only ten patients (2.89%). Main findings were focal thickening of the bladder wall (n = 6), ureteral dilatation (n = 3) and grade I hydronephrosis (n = 1). No malignant lesions, hepatic lesions nor hepatobiliary related disorders were found. After treatment, the S. haematobium global score (5 vs 3.4, p = 0.06) and the urinary bladder score (2 vs 1, p = 0.059) showed a trend towards improvement after treatment. In three patients the score after treatment dropped to 0, and in another three it remained the same although with signs of improvement. No worsening of the score was observed in any case.

CONCLUSION

For those patients with a diagnosis of schistosomiasis based solely in a positive serology, the ultrasound examination could safely be spared due to the low prevalence of pathological findings and its response to treatment anyway.

Associations between infection intensity categories and morbidity prevalence in school-age children are much stronger for Schistosoma haematobium than for S. mansoni

BACKGROUND

World Health Organization (WHO) guidelines for measuring global progress in schistosomiasis control classify individuals with Schistosoma spp. infections based on the concentration of excreted eggs. We assessed the associations between WHO infection intensity categories and morbidity prevalence for selected S. haematobium and S. mansoni morbidities in school-age children.

METHODOLOGY

A total of 22,488 children aged 6-15 years from monitoring and evaluation cohorts in Burkina Faso, Mali, Niger, Uganda, Tanzania, and Zambia from 2003-2008 were analyzed using Bayesian logistic regression. Models were utilized to evaluate associations between intensity categories and the prevalence of any urinary bladder lesion, any upper urinary tract lesion, microhematuria, and pain while urinating (for S. haematobium) and irregular hepatic ultrasound image pattern (C-F), enlarged portal vein, laboratory-confirmed diarrhea, and self-reported diarrhea (for S. mansoni) across participants with infection and morbidity data.

PRINCIPAL FINDINGS

S. haematobium infection intensity categories possessed consistent morbidity prevalence across surveys for multiple morbidities and participants with light infections had elevated morbidity levels, compared to negative participants. Conversely, S. mansoni infection intensity categories lacked association with prevalence of the morbidity measures assessed.

CONCLUSIONS/SIGNIFICANCE

Current status infection intensity categories for S. haematobium were associated with morbidity levels in school-age children, suggesting urogenital schistosomiasis morbidity can be predicted by an individual's intensity category. Conversely, S. mansoni infection intensity categories were not consistently indicative of childhood morbidity at baseline or during the first two years of a preventive chemotherapy control program.

Ultrasound Evolution of Pediatric Urinary Schistosomiasis after Treatment with Praziquantel in a Highly Endemic Area

Urinary schistosomiasis causes damage to the urological system. Ultrasound is a method that detects the burden of secondary disease, individually and in epidemiological studies. In this study, the Schistosoma haematobium-associated urinary tract pathology is analyzed before and after treatment in a short period of time. Seventy children who had previously participated in an epidemiological study on schistosomiasis in the city of Cubal, Angola, and had also performed urinary ultrasound between August 2013 and February 2014 were cited 6-8 months later to assess the possible reinfection and repeat new urinary ultrasound, analyzing changes at the level of urinary pathology. The presence of hematuria and proteinuria was also analyzed. Of the 70 children analyzed, 29 (41.4%) were girls, with an average age of 10.4 years (standard deviation 2.3). Fifty-three (75.7%) had an improvement in their bladder and/or kidney scores, whereas 12 (17.1%) had no change and five (7.1%) had progression of the disease. None of the parameters analyzed completely disappeared. After one single course of treatment with praziquantel, all the analyzed parameters showed regression. Improvement was greater in the urinary bladder than in the upper urinary tract, though these lesions also reversed; the reversion of all parameters was greater among children older than 10 years old than the younger ones. Proteinuria was the parameter with a smaller reduction. Ultrasound should be a usual tool for diagnosis and follow-up in urinary schistosomiasis, particularly in children; more accurate recommendations about follow-up in the case of children whose lesions do not reverse should be established.

The diagnosis and treatment of urogenital schistosomiasis in Italy in a retrospective cohort of immigrants from Sub-Saharan Africa

OBJECTIVES

To evaluate ultrasound and praziquantel to, respectively, assess and reduce urogenital schistosomiasis (UGS)-associated morbidity in migrants from Sub-Saharan Africa (SSA).

METHODS

Migrants from SSA with UGS attending three Italian centres for tropical diseases during 2011-2016 were retrospectively enrolled. Data on clinical symptoms, routine laboratory, parasitological tests, and ultrasound reported as per the WHO-Niamey protocol were collected at baseline and at available follow-up visits after treatment with praziquantel 40 mg/kg/day for 3 days.

RESULTS

One hundred and seventy patients with UGS were enrolled and treated with praziquantel. Baseline ultrasonography showed urinary tract abnormalities in 115/169 patients (68%); the mean global Schistosoma haematobium score was 2.29 (SD 2.84, IQR 0-2), the mean urinary bladder intermediate score 1.75 (SD 1.73, IQR 0-2), and the mean upper urinary tract intermediate score 0.54 (SD 2.37, IQR 1-10). Abnormalities were more common among the 111 (65%) who were symptomatic (p < 0.02; OR 2.53; 95% CI 1.19-5.35). Symptoms started in 94/111 (85%) before arriving (median 63 months, IQR 12-119). At follow-up, we observed a significant reduction in the prevalence of UGS-related symptoms, blood, urine, and ultrasound abnormalities.

CONCLUSIONS

Our study results support the use of ultrasound and praziquantel for assessing and reducing UGS-associated morbidity in migrants. Health-seeking behaviour, diagnostic, and treatment delays contribute to the advanced pathology and qualified treatment success. To ensure earlier treatment, based on our findings, clinical experience, and available literature, we propose an algorithm for the diagnosis and clinical management of UGS. Multicentre studies are needed to improve the management of subjects with UGS in non-endemic countries.

Mass drug administration and the global control of schistosomiasis: successes, limitations and clinical outcomes

PURPOSE OF REVIEW

Preventive chemotherapy is advocated for the global control and elimination of schistosomiasis. Despite the well known short-term benefits of treating patients for schistosomiasis, the impact of mass drug administration (MDA) campaigns to control the disease in the long term remains unresolved.

RECENT FINDINGS

Many studies have advocated the success of MDA programs in order to attract donor funds for elimination efforts but such successes are often short-lived given the drug does not alter the life cycle of the organism or prevent reinfection. Within a matter of months to years after halting treatment, the prevalence, intensity of infection and morbidity of disease return to baseline levels. Other mitigating factors contribute to the failings of MDA campaigns namely: poverty, poor drug coverage, poor drug compliance, and, in the case of Asiatic schistosomiasis, zoonotic transmission. Genetic and innate and acquired immunologic mechanisms complicate the epidemiologic picture of schistosomiasis globally, and may contribute indirectly to MDA shortcomings. The possibility of drug resistance is an ever present concern because of the sole reliance on one drug, praziquantel.

SUMMARY

Preventive chemotherapy is advocated for the global control and elimination of schistosomiasis. The short-term benefits of MDA campaigns are well documented but the long-term benefits are questionable.

Evaluation of a Mobile Phone-Based Microscope for Screening of Schistosoma haematobium Infection in Rural Ghana

AbstractSchistosomiasis affects over 170 million people in Africa. Here we compare a novel, low-cost mobile phone microscope to a conventional light microscope for the label-free diagnosis of Schistosoma haematobium infections in a rural Ghanaian school setting. We tested the performance of our handheld microscope using 60 slides that were randomly chosen from an ongoing epidemiologic study in school-aged children. The mobile phone microscope had a sensitivity of 72.1% (95% confidence interval [CI]: 56.1-84.2), specificity of 100% (95% CI: 75.9-100), positive predictive value of 100% (95% CI: 86.3-100), and a negative predictive value of 57.1% (95% CI: 37.4-75.0). With its modest sensitivity and high specificity, this handheld and cost-effective mobile phone-based microscope is a stepping-stone toward developing a powerful tool in clinical and public health settings where there is limited access to conventional laboratory diagnostic support.

Ultrasonographic evaluation of urinary tract morbidity in school-aged and preschool-aged children infected with Schistosoma haematobium and its evolution after praziquantel treatment: A randomized controlled trial

Background

Schistosoma haematobium infections are responsible for significant urinary tract (UT) complications. Schistosomiasis control programs aim to reduce morbidity, yet the extent of morbidity in preschool-aged children and the impact of treatment on morbidity reduction are not well studied.

Methodology

Our study was embedded in a randomized, placebo-controlled, single-blind trial in Côte d’Ivoire, which evaluated the efficacy and safety of three doses (20, 40 and 60 mg/kg) of praziquantel in school-aged (SAC) and preschool-aged (PSAC) children infected with S. haematobium. Enrolled children were invited to participate in an ultrasound examination prior and six months after treatment. At these time points 3 urine samples were collected for parasitological and clinical examinations.

Principal findings

162 PSAC and 141 SAC participated in the ultrasound examination at baseline, of which 128 PSAC and 122 SAC were present at follow-up. At baseline 43% (70/162) of PSAC had UT morbidity, mostly at bladder level and 7% had hydronephrosis. 67% (94/141) of SAC revealed mainly moderate UT pathology, 4% presented pseudopolyps on the bladder wall, and 6% had pyelectasis. At follow up, 45% of PSAC and 58% of SAC were S. haematobium positive, mostly harboring light infection intensities (41% and 51%, respectively). Microhematuria was present in 33% of PSAC and 42% of SAC and leukocyturia in 53% and 40% of PSAC and SAC, respectively. 50% (64/128) of PSAC and 58% (71/122) of SAC presented urinary tract morbidity, which was mainly mild. A significant correlation (p<0.05) was observed between praziquantel treatment and reversal of S. haematobium induced morbidity. Progression of UT pathology decreased with increasing praziquantel dosages. A worsening of morbidity was observed among children in the placebo group.

Conclusion/Significance

Bladder morbidity is widespread among PSAC. Praziquantel treatment is significantly associated with the reversal of S. haematobium induced morbidity, which underscores the importance of preventive chemotherapy programs. These programs should be expanded to PSAC to prevent or decrease the prevalence of morbidity in young children. This trial is registered as an International Standard Randomized Controlled Trial, number ISRCTN15280205.

Schistosoma haematobium is a parasite that infects the human genito-urinary tract. People get infected with the parasite through contact with fresh water and children are at major risk. The complications linked to this infection are due to an inflammation caused by accumulation of the eggs in peri-bladder veins. If not treated, infections can last years and different degrees of severity are observed. These range from thickening of the bladder wall and blurriness of the mucosa to more serious lesions such as pseudo polyps and masses in the bladder that can, with time, evolve in cancer of the bladder. We analyzed preschool-aged children (PSAC) and school-aged children (SAC) with ultrasound before and after praziquantel treatment. Children were randomly assigned to different doses of praziquantel (20, 40 or 60 mg/kg) or to placebo at baseline. Six months after treatment all children underwent another ultrasound of the urinary tract. We included 162 PSAC and 141 SAC at baseline, of which 128 PSAC and 122 SAC had a second ultrasound evaluation six months afterwards. In addition, urine was sampled at both time points for presence of blood, proteins and signs of infection (leukocytes and nitrates). Six months post-treatment 45% of PSAC and 58% of SAC were S. haematobium positive. Already at the first screening 43% of PSAC and 67% of SAC had bladder lesions. After treatment 50% of PSAC and 58% of SAC still had pathology linked to the infection. We found a correlation between the treatment dose and healing of bladder lesions. On the other hand, we experienced an aggravation of lesions in the placebo group. Praziquantel is given to SAC as preventive chemotherapy every year at national level, where this parasite is endemic. This program should be expanded and include PSAC as well in order to reduce the consequences of infection.

Decline in infection-related morbidities following drug-mediated reductions in the intensity of Schistosoma infection: A systematic review and meta-analysis

Background

Since 1984, WHO has endorsed drug treatment to reduce Schistosoma infection and its consequent morbidity. Cross-sectional studies suggest pre-treatment correlation between infection intensity and risk for Schistosoma-related pathology. However, evidence also suggests that post-treatment reduction in intensity may not reverse morbidity because some morbidities occur at all levels of infection, and some reflect permanent tissue damage. The aim of this project was to systematically review evidence on drug-based control of schistosomiasis and to develop a quantitative estimate of the impact of post-treatment reductions in infection intensity on prevalence of infection-associated morbidity.

Methodology/Principal findings

This review was registered at inception with PROSPERO (CRD42015026080). Studies that evaluated morbidity before and after treatment were identified by online searches and searches of private archives. Post-treatment odds ratios or standardized mean differences were calculated for each outcome, and these were correlated to treatment-related egg count reduction ratios (ERRs) by meta-regression. A greater ERR correlated with greater reduction in odds of most morbidities. Random effects meta-analysis was used to derive summary estimates: after treatment of S. mansoni and S. japonicum, left-sided hepatomegaly was reduced by 54%, right-sided hepatomegaly by 47%, splenomegaly by 37%, periportal fibrosis by 52%, diarrhea by 53%, and blood in stools by 75%. For S. haematobium, hematuria was reduced by 92%, proteinuria by 90%, bladder lesions by 86%, and upper urinary tract lesions by 72%. There were no consistent changes in portal dilation or hemoglobin levels. In sub-group analysis, age, infection status, region, parasite species, and interval to follow-up were associated with meaningful differences in outcome.

Conclusion/Significance

While there are challenges to implementing therapy for schistosomiasis, and praziquantel therapy is not fully curative, reductions in egg output are significantly correlated with decreased morbidity and can be used to project diminution in disease burden when contemplating more aggressive strategies to minimize infection intensity.

Schistosomiasis is the disease caused by infection with Schistosoma parasitic flukes. Depending on the infecting species, chronic Schistosoma infection can cause a variety of pathologies including liver and spleen enlargement, fibrosis and hypertension of the portal vein of the liver, or bladder ulceration and deformities and kidney blockage. Infection can also cause anemia, diarrhea, abdominal pain, and decreased physical fitness. In our study, we quantified the reductions in prevalence of infection-related morbidities among populations with Schistosoma infection, as achieved by giving one or more drug treatments. We systematically reviewed 71 available reports of Schistosoma-related morbidity reduction and determined, based on a meta-analysis of the primary data, that the odds of persisting morbidity progressively decrease when greater post-treatment reductions in parasite burden are achieved, as reflected by reduced egg counts in standard diagnostic testing. This suggests that repeated or more effective anti-parasite drug treatment will be a valuable tool for greater reduction of Schistosoma-related patient morbidities in affected areas.

Cervical cytology as a diagnostic tool for female genital schistosomiasis: Correlation to cervical atypia and Schistosoma polymerase chain reaction

Background:

Female genital schistosomiasis (FGS) is a tissue reaction to lodged ova of Schistosoma haematobium in the genital mucosa. Lesions can make the mucosa friable and prone to bleeding and discharge. Women with FGS may have an increased risk of HIV acquisition, and FGS may act as a cofactor in the development of cervical cancer.

Objectives:

To explore cytology as a method for diagnosing FGS and to discuss the diagnostic challenges in low-resource rural areas. The correlation between FGS and squamous cell atypia (SCA) is also explored and discussed. Cytology results are compared to Schistosoma polymerase chain reaction (PCR) in vaginal lavage and urine and in urine microscopy.

Materials and Methods:

In a clinical study, 394 women aged between 16 and 23 years from rural high schools in KwaZulu-Natal, South Africa, underwent structured interviews and the following laboratory tests: Cytology Papanicolaou (Pap) smears for S. haematobium ova and cervical SCA, real-time PCR for Schistosoma-specific DNA in vaginal lavage and urine samples, and urine microscopy for the presence of S. haematobium ova.

Results:

In Pap smears, S. haematobium ova were detected in 8/394 (2.0%). SCA was found in 107/394 (27.1%), seven of these had high-grade squamous intraepithelial lesion (HSIL). Schistosoma specific DNA was detected in 38/394 (9.6%) of vaginal lavages and in 91/394 (23.0%) of urines. Ova were found microscopically in 78/394 (19.7%) of urines.

Conclusion:

Schistosoma PCR on lavage was a better way to diagnose FGS compared to cytology. There was a significant association between S. haematobium ova in Pap smears and the other diagnostic methods. In low-resource Schistosoma-endemic areas, it is important that cytology screeners are aware of diagnostic challenges in the identification of schistosomiasis in addition to the cytological diagnosis of SCA. Importantly, in this study, three of eight urines were negative but showed Schistosoma ova in their Pap smear, and one of them was also negative for Schistosoma DNA in urine. In this study, SCA was not significantly associated with schistosomiasis. HSIL detected in this young population might need future consideration.

Schistosomiasis elimination by 2020 or 2030?

Schistosomiasis has been a public health burden in a number of countries across the globe for centuries and probably beyond. The World Health Organization and partners are currently preparing to move towards elimination of this disease. However, given the historical challenges and barriers to ridding areas of this water-borne parasite infection, we question whether the current targets for eliminating schistosomiasis as a global health problem can be achieved.

Application of Ultrasonography in the Diagnosis of Infectious Diseases in Resource-Limited Settings

Ultrasound (US) has vast potential in the field of infectious diseases, especially so in resource-limited settings. Recent technological advances have increased availability and access to ultrasound in low-resource settings, where the burden of infectious diseases is greatest. This paper collates the evidence for the utilization of ultrasound and evaluates its effectiveness in the diagnosis and management of a range of infectious diseases. This paper explores the role of ultrasound in population-based screening for specific diseases as well as highlights its benefits for individual patient management. We describe the common diagnostic signs seen on US for common and neglected parasitic, bacterial, and viral diseases. We proceed to document the emerging field of chest US which is proving to be a superior imaging modality for the diagnosis of specific pulmonary conditions. We conclude by discussing the efforts needed to formalize and rigorously evaluate the role of ultrasound in infectious diseases.