Urinary tract morbidity due to Schistosoma haematobium infection in Mali

Urogenital schistosomiasis among school children in northwestern Tanzania: Prevalence, intensity of infection, associated factors, and pattern of urinary tract morbidities

Background

The planning and implementation of intervention measures against schistosomiasis, particularly mass administration, require knowledge of the current status of the infection. This is important for monitoring the impact of the intervention on disease indicators such as a decline in infection prevalence, intensity of infection, and urogenital morbidities. Following repeated rounds of mass treatment in northwestern Tanzania, the epidemiology of urogenital schistosomiasis has changed; thus, for the effective planning and allocation of resources, it is important to understand the current status of the disease in the targeted groups. Therefore, the objective of the current study was to determine the prevalence, intensity, and associated factors of Schistosoma haematobium infection and urinary tract morbidities in school-aged children from northwestern Tanzania.

Materials and methods

An analytical cross-sectional study was conducted among schoolchildren aged 5-17 years between November and December 2022. A single urine sample was collected from each child and examined for the presence of S. haematobium eggs and microhaematuria using a urine filtration technique and a urine reagent dipstick. Each child underwent an ultrasonographic examination of the urinary tract according to the World Health Organization standards (Niamey protocol) to detect S. haematobium-related morbidities.

Results

Of the 3225 participants, 54.2 % were female, and the mean age was 10.9 (±1.89) years. The overall prevalence of S. haematobium was 17.7 % (95 % CI: 16.4-19.1, 572/3225). Of the 572 infected children, 81.8 % (95 % CI: 78.4-84.9, 468/572) had light-intensity infections, and 18.2 % (95 % CI: 14.9-21.4, 104/572) had heavy-intensity infections. The prevalence of macro- and microhaematuria was 2.4 % (95 % CI: 1.9-3) and 18.5 % (95 % CI: 17.2-19.8), respectively. Age (aOR: 1.2, 95 % CI: 1.0-1.5), district of residence (aOR: 2.1, 95 % CI: 1.7-2.7) and history of schistosomiasis (aOR: 2.5, 95 % CI: 1.9-3.2) were significantly associated with urinary schistosomiasis infection. However, swallowing praziquantel during the last mass drug administration was protective (aOR 0.6, 95 % CI: 0.4-0.8). The overall prevalence of ultrasound-detectable urinary tract abnormalities was 9.9 % (95 % CI: 8.9-11.1, 299/2994) and included urinary bladder abnormalities in 9.9 % (95 % CI: 8.8-11, 297/2994), ureter abnormalities in 0.2 % (95 % CI: 0.07-0.4, 6/2994), and kidney abnormalities in 0.2 % (95 % CI: 0.09-0.4, 7/2994). Calcification of the urinary bladder was observed in 0.9 % (95 % CI: 0.6-1.3, 29/2994) of the examined children.

Conclusions

Schistosoma haematobium infection is still prevalent among schoolchildren in the study setting, and it causes substantial morbidity at an early age. Transmission is driven by the age of the child, district of residence, and history of schistosomiasis. However, swallowing praziquantel in rounds of mass drug administration reduces transmission. Urogenital schistosomiasis infection is associated with haematuria and ultrasound-detectable morbidities. In S. haematobium endemic areas, routine ultrasound screening for urinary tract morbidities could be considered in annual mass treatment programmes for early management. Special attention should be given to children with proteinuria, microhaematuria, and heavy infection intensities.

Diagnosis and management of complicated urogenital schistosomiasis: a systematic review of the literature

BACKGROUND

Currently, there are no standardized guidelines for the diagnosis or management of the complications of urogenital schistosomiasis (UGS). This systematic review of the literature aims to investigate the state of the art in reference to diagnostic approaches and the clinical management of this condition.

METHODS

A systematic review of literature published between January 1990 and January 2021 was conducted in the MEDLINE database, scoping for articles regarding diagnostic means or therapeutic options for the complications of UGS, namely obstructive uropathy, bladder cancer, abortion, ectopic pregnancy, infertility, kidney failure, urolithiasis and the need for invasive procedures. Relevant data were then extracted from the articles deemed eligible according to the inclusion criteria.

MAIN RESULTS

In total, 3052 articles were identified by the research query, of which 167 articles fulfilling inclusion criteria after title/abstract screening and full-text evaluation were included, 35% on both diagnostic and therapeutic aspects, and 51% on diagnosis and 14% on therapy. Ultrasound was the most frequently tool employed for the diagnosis of UGS complications showing a good performance. Concerning the management of hydronephrosis, the majority of available evidences came from community-based studies where universal treatment with praziquantel was used leading to decrease of prevalence of obstructive uropathy. Concerning studies on surgical procedures, laser endoureterotomy followed by stenting was mostly employed in adult patients leading to a crude cure rate of 60% (43 of 71 patients). In the case of severe hydronephrosis, surgery consisting of ureteral re-implantation showed excellent results with a crude cure rate of 98% (157 cured patients of 160 treated). Concerning bladder cancer, data on 93 patients with a clear diagnosis of UGS-related bladder were available reporting a variable and sometime combined approach based on disease stage. Available data on diagnosis and management of abortion, ectopic pregnancy, infertility, kidney failure, urolithiasis and the need for invasive procedures due to UGS are also presented.

CONCLUSIONS

The review produced a complete picture of the diagnostic and therapeutic options currently available for complicated UGS. These results can be useful both for guiding clinicians towards correct management and for tracing the direction of future research.

Schistosoma haematobium urinary tract complications in African migrants attending primary care facilities in Paris, France: A retrospective cohort study (2004-2018)

OBJECTIVES

Little is known about the burden of urogenital schistosomiasis (UGS) outside endemic areas. This study was aimed at describing urinary complications of UGS detected among African migrants in French primary care facilities.

PATIENTS AND METHODS

A retrospective cohort study included patients with UGS diagnosed from 2004 to 2018 in 5 primary health centers in Paris. Cases were defined by the presence of typical Schistosoma haematobium eggs at urine microscopy. Demographic, clinical, biological and imaging data were collected. Ultrasonography (U-S) findings were classified in accordance with the WHO guidelines.

RESULTS

U-S was prescribed for all patients and performed in 100/118. Sex ratio (F/M) was 2/98, and mean age 24.4 years. Patients were from West Africa (73% from Mali) and consulted 8 months (median) after their arrival. Among the 95 patients with interpretable findings, 32 (33.7%) had abnormalities related to UGS, considered as major in 6 cases (6.3%), and mostly localized at the bladder (31/32) without detection of cancer. No sociodemographic, clinical, or biological factors were found to be associated with U-S abnormalities. All 100 patients were treated by praziquantel (PZQ). Among those with abnormalities, 20/32 received two to four doses at various time intervals. Post-cure imaging control performed in 19/32 showed persistent abnormalities in 6 patients, on average 5 months after the last PZQ uptake.

CONCLUSION

Urinary tract abnormalities associated with UGS were common and predominated at the bladder. U-S should be prescribed to any patient with positive urine microscopy. Schedules for PZQ uptake and U-S monitoring for patients with complications remain to be determined.

Urogenital schistosomiasis during pregnancy is associated with low birth weight delivery: analysis of a prospective cohort of pregnant women and their offspring in Gabon

An estimated 40 million women of childbearing age suffer from schistosomiasis. Animal models indicate a deleterious effect of maternal schistosomiasis on pregnancy outcomes. To date there is a lack of epidemiological evidence evaluating schistosomiasis-related morbidity in pregnancy. This study was designed to describe the impact of urogenital schistosomiasis on pregnancy outcomes in a highly endemic region of central Africa. Pregnant women attending antenatal clinics in Fougamou and Lambaréné, Gabon, were consecutively screened for the presence of Schistosoma haematobium eggs in diurnal urine samples. Maternal and newborn characteristics assessed at delivery were compared between infected and uninfected mothers. The impact of maternal schistosomiasis on low birth weight and preterm delivery was assessed using logistic regression analysis. Urogenital schistosomiasis was diagnosed in 103 (9%) of 1115 pregnant women. Maternal age was inversely associated with the prevalence of urogenital schistosomiasis, with a higher burden amongst nulliparous women. Low birth weight was more common amongst infants of S. haematobium-infected mothers. This association was unaffected by controlling for demographic characteristics, gestational age and Plasmodium infection status (adjusted Odds Ratio 1.93; 95% confidence interval: 1.08-3.42). Other risk factors associated with low birth weight delivery were underweight mothers (adjusted Odds Ratio 2.34; 95% confidence interval: 1.12-4.92), peripheral or placental Plasmodium falciparum infection (adjusted Odds Ratio 2.04; 95% confidence interval: 1.18-3.53) and preterm birth (adjusted Odds Ratio 3.12; 95% confidence interval: 1.97-4.96). Preterm delivery was not associated with S. haematobium infection (adjusted Odds Ratio 1.07 95% confidence interval: 0.57-1.98). In conclusion, this study indicates that pregnant women with urogenital schistosomiasis are at an increased risk for low birth weight deliveries. Further studies evaluating targeted treatment and prevention programmes for urogenital schistosomiasis in pregnant women and their impact on delivery outcomes are warranted.

Kidney disease among children in sub-Saharan Africa: systematic review

The global burden of kidney disease is increasing, and several etiologies first begin in childhood. Risk factors for pediatric kidney disease are common in Africa, but data regarding its prevalence are lacking. We completed a systematic review of community-based studies describing the prevalence of proteinuria, hematuria, abnormal imaging, or kidney dysfunction among children in sub-Saharan Africa (SSA). Medline and Embase were searched. Five hundred twenty-three references were reviewed. Thirty-two references from nine countries in SSA were included in the qualitative synthesis. The degree of kidney damage and abnormal imaging varied widely: proteinuria 32.5% (2.2-56.0%), hematuria 31.1% (0.6-67.0%), hydronephrosis 11.3% (0.0-38.0%), hydroureter 7.5% (0.0-26.4%), and major kidney abnormalities 0.1% (0.0-0.8%). Serum creatinine was reported in four studies with insufficient detail to identify the prevalence renal dysfunction. A majority of the studies were performed in Schistosoma haematobium endemic areas. A lower prevalence of kidney disease was observed in the few studies from nonendemic areas. Published data on pediatric kidney disease in SSA are highly variable and dependent on S. haematobium prevalence. More community-based studies are needed to describe the burden of pediatric kidney disease, particularly in regions where S. haematobium infection is nonendemic.

The colposcopic atlas of schistosomiasis in the lower female genital tract based on studies in Malawi, Zimbabwe, Madagascar and South Africa

BACKGROUND

Schistosoma (S.) haematobium is a neglected tropical disease which may affect any part of the genital tract in women. Female genital schistosomiasis (FGS) may cause abnormal vaginal discharge, contact bleeding, genital tumours, ectopic pregnancies and increased susceptibility to HIV. Symptoms may mimic those typical of sexually transmitted infections (STIs) and women with genital schistosomiasis may be incorrectly diagnosed. An expert consensus meeting suggested that the following findings by visual inspection should serve as proxy indicators for the diagnosis of schistosomiasis of the lower genital tract in women from S. haematobium endemic areas: sandy patches appearing as (1) single or clustered grains or (2) sandy patches appearing as homogenous, yellow areas, or (3) rubbery papules. In this atlas we aim to provide an overview of the genital mucosal manifestations of schistosomiasis in women.

METHODOLOGY/PRINCIPAL FINDINGS

Photocolposcopic images were captured from women, between 1994 and 2012 in four different study sites endemic for S. haematobium in Malawi, Zimbabwe, South Africa and Madagascar. Images and specimens were sampled from sexually active women between 15 and 49 years of age. Colposcopic images of other diseases are included for differential diagnostic purposes.

SIGNIFICANCE

This is the first atlas to present the clinical manifestations of schistosomiasis in the lower female genital tract. It will be freely available for online use, downloadable as a presentation and for print. It could be used for training purposes, further research, and in clinical practice.

Impact of Schistosoma haematobium infection on urinary tract pathology, nutritional status and anaemia in school-aged children in two different endemic areas of the Niger River Basin, Mali

The aim of the present study was to contribute to define urinary schistosomiasis-related morbidity indicators and to understand the relationship between infection intensity and disease burden among school-aged children in different endemic areas of Mali. A cross sectional study was undertaken in two different endemic settings: Koulikoro district, along the river and Selingué dam area in the Niger River Basin in order to compare and describe morbidity related to Schistosoma haematobium infection. A total of 667 children aged 7-14 were enrolled in the study. Among these, 333 were from Koulikoro district (175 boys and 158 girls) and 334 from Selingué dam area (169 boys and 165 girls). The overall prevalence of S. haematobium in the two areas was 91.5%; Koulikoro (97.0%) and Selingué (85.9%) and this difference was significant after adjusting for age, sex and clustering within villages. Prevalence of heavy infection (≥ 50 eggs per 10 ml of urine), 57.6% in Koulikoro and 43.8% in Selingué, did not differ significantly after adjusting for age, sex and clustering within villages. The transmission of Schistosoma mansoni was mainly confined to Selingué dam area (12.5%) and was nearly absent in Koulikoro district (1.1%). Blood in urine was the most frequently reported clinical symptom, more common in Koulikoro (76.8%) than in Selingué (57.6%). In a multivariable logistic regression model adjusting for sex, age group, egg intensity category and clustering within villages, Selingué had higher prevalence of macro-haematuria, urinary tract pathology, upper urinary tract pathology and total pathology than Koulikoro, while micro-haematuria did not differ between the two areas. Morbidity measures increased to some extent with egg intensity category, especially micro-haematuria. The results obtained from this study are of importance for planning intervention as for monitoring and evaluation of control in different endemic settings in Mali.

Use of Bayesian geostatistical prediction to estimate local variations in Schistosoma haematobium infection in western Africa

OBJECTIVE

To predict the subnational spatial variation in the number of people infected with Schistosoma haematobium in Burkina Faso, Mali and the Niger prior to national control programmes.

METHODS

We used field survey data sets covering a contiguous area 2750 x 850 km and including 26,790 school-age children (5-14 years old) in 418 schools. The prevalence of high- and low-intensity infection and associated 95% credible intervals (CrIs) were predicted using Bayesian geostatistical models. The number infected was determined from the predicted prevalence and the number of school-age children in each km(2).

FINDINGS

The predicted number of school-age children with a low-intensity infection was 433,268 in Burkina Faso, 872,328 in Mali and 580 286 in the Niger. The number with a high-intensity infection was 416,009, 511,845 and 254,150 in each country, respectively. The 95% CrIs were wide: e.g. the mean number of boys aged 10-14 years infected in Mali was 140,200 (95% CrI: 6200-512,100).

CONCLUSION

National aggregate estimates of infection mask important local variations:: e.g. most S. haematobium infections in the Niger occur in the Niger River valley. High-intensity infection was strongly clustered in western and central Mali, north-eastern and northwestern Burkina Faso and the Niger River valley in the Niger. Populations in these foci will carry the bulk of the urinary schistosomiasis burden and should be prioritized for schistosomiasis control. Uncertainties in the predicted prevalence and the numbers infected should be acknowledged by control programme planners.

Genital schistosomiasis in women: a clinical 12-month in vivo study following treatment with praziquantel

Urinary schistosomiasis is known to be associated with lesions in the female genital organs, particularly with the presence of 'sandy patches' in the lower genital tract. This study sought to determine the effect of treatment with praziquantel on gynaecological schistosomiasis in residents of an area endemic for Schistosoma haematobium. A cohort study was conducted among women aged 20-49 years in rural Zimbabwe. The shape and size of lesions were mapped pre treatment and 3 and 12 months following treatment. Ova of S. haematobium were looked for in cytology smears, wet mounts, biopsies, urine and stool. Specimens were collected for detection of sexually transmitted diseases and cancer. At baseline, almost half of the 527 women included in the study had sandy patches. Although urinary ova excretion decreased following treatment (odds ratio 10.3, 95% CI 3.8-27.8, P<0.001), praziquantel treatment was not associated with a significant reduction in genital lesions or contact bleeding (P=0.31-0.94). Sandy patches remained strongly associated with contact bleeding and vessel abnormalities even after treatment. Findings were independent of HIV status. Such lesions, which are common and apparently refractory to treatment for at least 12 months, may be an important risk factor for both the acquisition and transmission of HIV.

The impact of chemotherapy on morbidity due to schistosomiasis

Current knowledge on the impact of chemotherapy on schistosomiasis-related morbidity is still fragmentary. In urinary schistosomiasis, reversal of organ pathology follows cure after 6 months and resurgence takes place after at least another 6 months. Retreatment after less than 1 year is, therefore, unnecessary. Also, intestinal schistosomiasis appears to regress promptly after chemotherapy. For the reversal of hepatic morbidity, more than one chemotherapy round appears necessary at least in foci of intense transmission of schistosomiasis. The earlier chemotherapy is given, the higher the chances of reversal of schistosomal pathology, but pathology may regress to some extent also in adults. The regression and resurgence of periportal fibrosis, as detected by ultrasonography, occurs with a delay of 7 months to more than 2 years after therapy. Retreatment after less than 1 year may not permit full assessment of the impact of the first round on hepatic morbidity. Children and adolescents should be the major target population, taking into account that in many foci, children out-of-school must be covered because they are at the highest risk. Repeated treatment during childhood may prevent the development of urinary tract disease in adulthood. However, no data are available on the prevention of genital pathology. Repeated chemotherapy may have a long term effect on re-infection intensities and the development of severe morbidity, even in foci where control has been interrupted for many years. Severe hepatic fibrosis may be prevented even in foci of intense transmission provided more than two rounds of chemotherapy have been given in childhood and that chemotherapy is available on demand. Chemotherapy has an important impact on child development, physical fitness and working capacity. Its effect on growth and anemia is improved by simultaneous treatment of intestinal parasites and the provision of adequate iron supplementation. The impact of chemotherapy on many of the multifaceted manifestations of schistosomiasis has not been assessed systematically. More data are needed on gallbladder pathology, neuroschistosomiasis, endocrinologic disorders, bladder cancer and co-infections with other pathogens. In areas where control has been achieved, the overall morbidity and mortality has decreased with a delay of many years or even decades.

Epidemiological assessment of Schistosoma haematobium-induced kidney and bladder pathology in rural Zimbabwe

Clinical outcome of Schistosoma haematobium infection may vary significantly, ranging from mild symptoms to severe damage of urinary tract organs. This present study was undertaken to assess the relationship of a number of epidemiological and parasitological parameters with disease outcome in children from rural Zimbabwe. We surveyed 551 primary school students from three schools in the Chikwaka Communal Lands for schistosomiasis; 59.7% were infected with S. haematobium. Ultrasound examination of 189 of the infected students revealed that 50% had pathological changes of their bladder and 36% had abnormal pyelon dilation of at least one of their kidneys. Intensity of infection, certain water contact behaviours, male gender, proteinuria, and self-perceived haematuria were associated with increased bladder damage. Strenuous playing was negatively associated with pathology, especially for those with the highest grade of bladder damage. Kidney pathology was significantly linked with fatigue and pain upon urination and was more prevalent in students from schools closest to the major river systems. Our findings suggest that pathology due to urinary schistosomiasis is widespread and symptomatic in this population. The associations with bladder and kidney pathology can be used to predict disease severity and may be useful in targeting treatment to those most at risk.

Nephropathy associated with animal, plant, and chemical toxins in the tropics

Widespread human exposure to a variety of drugs, chemicals, and biologic products and recent awareness of their toxic manifestations has led to the recognition of toxic nephropathy as an important segment of renal disease in the tropical countries. Tropical nephrotoxins are distinctly different from those seen in the rest of the world and are derived from local fauna and flora or plant and chemical sources. The spectrum of exposure varies from country to country and even from community to community, depending on variations in the distribution of local plants and animal species and prevalent social practices. Acute renal failure (ARF), either alone or in association with liver failure, neurologic abnormalities, metabolic acidosis, disseminated intravascular coagulation, or pulmonary infections is the most common form of presentation. Traditional medicines prescribed by witch doctors (traditional healers) constitute a special class of nephrotoxins among several communities in Africa and Asia. The prevalence of nephropathy caused by traditional medicines is directly related to a combination of ignorance, poverty, lack of medical facilities, lax legislation, and widespread belief in indigenous systems of medicine in rural areas. These medicines are a mix of herbs and unknown chemicals administered orally or as enemas. Clustering of cases after exposure to a particular agent suggests the possibility of a toxic insult. Common animal nephrotoxins are venoms of viper snakes, sea snakes, stinging insects, and raw gallbladder and bile of carp and sheep. Botanical nephrotoxins are encountered both in common edible plants (djenkol beans, mushrooms) and medicinal herbs (impila, cat's claw). Mistaken identification of medicinal herbs by untrained workers and even deliberate trials of toxic substitutes derived from plants frequently lead to renal disease, the most commonly reported being the Chinese herbal nephropathy. Nephrotoxicity caused by chemicals can be secondary to accidental occupational exposure in industrial work places (eg, chromic acid), or after suicidal or homicidal use (eg, copper sulphate, ethylene dibromide, ethylene glycol). Late presentation and multiorgan dysfunction are associated with a high mortality. A high index of suspicion, careful history taking, and an awareness of local practices are essential for proper diagnosis and management of toxic nephropathies in the tropics.

Evolution of schistosomiasis-induced pathology after therapy and interruption of exposure to schistosomes: a review of ultrasonographic studies

Ultrasonography (US) is suitable for diagnosing schistosomiasis-related organic pathology and is particularly useful to assess its evolution after therapy and/or interruption of exposure to the Schistosoma parasites. Evolution of pathology after treatment: Regression of hepatic abnormalities in Schistosma mansoni-infected children and adolescents has been observed already from 7 months post-therapy on. This does, however, not occur in all cases: individual differences are great ranging from spontaneous regression of pathology without treatment to persistence of pathology lasting for years after therapy even without re-infection. Intensity and duration of exposure, different parasite strains, patients' age and genetic background all influence the evolution of pathology. In communities at continuous exposure to S. mansoni infection, repeated re-treatment is required to control hepatosplenic morbidity. In Schistosoma japonicum infection, changes around the portal tree may regress, but characteristic diffuse abnormalities described as 'network pattern' abnormalities do not resolve. In Schistosoma haematobium infection bladder abnormalities and urinary tract obstruction frequently resolve after treatment. Clinically relevant pathology may resurge from 1 year after therapy on if exposure continues. Subjects with more advanced pathology before therapy, appear to be at higher risk of pathology re-appearance. Evolution of pathology after interruption of exposure to schistosomiasis: Knowledge on the evolution of pathology induced by S. mansoni is limited to some reports in emigrants and to the experience of ultrasonographists working in areas, where transmission has been partially interrupted. Due to the longevity of the parasite, infection may last for many years. Even after elimination of the parasites severe pathology may persist for long. In S. haematobium infection spontaneous healing after interruption of re-exposure may occur, but cases have been reported where urogenital lesions led to complications many years after exposure. Contrary to hepatosplenic and urinary pathology, knowlegde on the evolution of other organic abnormalities is very limited: studies on the evolution of biliary abnormalities or intestinal pathology have not been published. Genital pathology may be induced by all Schistosoma spp. Post-therapy evolution of genital schistosomiasis is largely ignored. In some European travellers partial regression of prostatic fibrosis has been described. Schistosomal adnexitis leading to infertility and/or ectopic pregnancy has been reported occurring many years after interruption of exposure. Ultrasonography (US) has never been used to study the influence of schistosomiasis on pregnancy. Concluding, current knowlegde on the evolution of pathology after treatment and/or interruption of exposure is still fragmentary. Frequently, fibrosis reverses after therapy, but advanced pathology may persist for long. Therefore, the possibility of severe clinical complications has to be taken into account, even if the infection is inactive since many years. In interventions aimed at controlling schistosomiasis-related morbidity, evolution of pathology must be monitored by US in representative patient cohorts. Further systematic US-studies are needed not only on the evolution of hepatosplenic and urinary pathology but also on that of intestinal, biliary and genital pathology induced by schistosomiasis, as well as on the influence of schistosomiasis on the outcome of pregnancy.