Persistent Urogenital Schistosomiasis and Its Associated Morbidity in Endemic Communities within Southern Ghana: Suspected Praziquantel Resistance or Reinfection?

Review of Recent Prevalence of Urogenital Schistosomiasis in Sub-Saharan Africa and Diagnostic Challenges in the Field Setting

Human schistosomiasis is one of neglected tropical diseases that remain highly prevalent in sub-Saharan Africa (SSA). Human schistosomiasis is mainly caused by two species, Schistosoma haematobium and S. mansoni, leading to urogenital and intestinal schistosomiasis, respectively. The World Health Organization (WHO) recommends mass drug administration (MDA) with praziquantel as the primary method of global intervention. Currently, MDA with praziquantel covers over half of the target population in endemic SSA countries. However, an accurate diagnosis is crucial for monitoring and evaluating the effectiveness of MDA. The standard diagnosis of both urogenital and intestinal schistosomiasis relies on the microscopic identification of eggs. However, the diagnostic sensitivity of this approach is low, especially for light or ultra-light infections. This is because Schistosoma eggs are laid inside of the venous plexus of the urinary bladder or mesenteric vein, where the adult flukes live. Approximately half of the eggs circulate in the blood vessels or are packed in neighboring tissues, while the remaining half are expelled into the lumen of the urinary bladder or intestine intermittently when the blood vessels are ruptured. In the field setting, the accuracy of any diagnostic method is critical for proper management of the intervention. The present article reviews the recent prevalence of urogenital schistosomiasis in SSA and highlights the practical limitations of diagnostic methods such as urine microscopy, urine reagent strips, molecular diagnosis, and ultrasound scanning in the field setting. Despite continuous global efforts to eliminate schistosomiasis over the past 20 years, many areas still remain endemic in SSA. No single diagnostic approach achieves acceptable sensitivity and specificity in the field setting. Therefore, any field survey should employ a combination of these methods based on the purpose of the study to accurately monitor and evaluate urogenital schistosomiasis. Based on diagnostic values and a cost-benefit analysis, a urine reagent strip test can replace urine microscopy in the field setting. The WHO criteria by ultrasound diagnosis should be updated including the echogenic snow sign and contour distortion.

Dynamics in Morbidity Markers and Cytological Observations Made in Urine of Schistosoma haematobium-Infected Children: Pre- and Post-Praziquantel Treatment in an Endemic Setting

Background: Schistosomiasis is a neglected tropical disease caused by helminths of the genus Schistosoma. Morbidity markers and cytological observations such as squamous metaplastic cells, inflammatory cells, and hyperkeratotic cells in the urine of S. haematobium-infected children may suggest disease severity. They may also help predict severe forms of clinical presentation, such as bladder cancer in later years, among infected ones who miss out on early detection and treatment. Insights into possible changes in the morbidity markers and cytological observations in the urine of these S. haematobium-infected children before and after treatment would be of high clinical importance. Aim: The aim of this study was to identify changes/dynamics in morbidity markers and cytological abnormalities in the urine deposits of S. haematobium-infected children, pre- and post-praziquantel treatment. Methodology: This was a longitudinal study involving baseline and follow-up sampling among basic school children living in schistosomiasis-endemic communities. Urine samples were collected from 520 children at baseline and examined for S. haematobium ova by microscopy, while urine chemistry analyses were used for the examination of morbidity markers. The cytological analyses involved cytopathological examination of the urine deposits. Children whose urine showed positivity for S. haematobium eggs were treated with a single oral dose of praziquantel (40 mg/kg), after which urine chemistry and cytological analyses were repeated weekly for comparison with baseline, until the eighth week. Results: Morbidity markers such as hematuria, proteinuria, and leukocyturia were detected both at baseline and post-treatment among the infected children (30/520). Hematuria was the predominant parameter (90%, 27/30) detected at baseline, followed by proteinuria (53.3%, 16/30). Leukocyturia was the rarest parameter detected at baseline (13.3%, 4/30). However, almost all these parameters declined gradually post-treatment. Regarding cytological analyses, inflammatory cells were observed most (70.0%, 21/30) at baseline. For hyperkeratotic cells and squamous metaplastic cells, 46.7% and 26.7% were respectively observed at baseline, all of which gradually declined during the weekly follow-ups. Notably, squamous metaplastic cells persisted in all the participants from Week 1 through Week 3 post-treatment, but declined gradually thereafter. Conclusions: Morbidity markers and cytological observations in the children gradually decreased after treatment. Therefore, we continue to recommend routine cytological screening for urogenital schistosomiasis patients at hospitals in S. haematobium-endemic locations using both baseline and follow-up samples to detect these abnormalities early and monitor changes that may be occurring after treatment. Such changes may be useful in assessing treatment progress in infected persons.