Evaluation of an ultrasonographic score for urinary bladder morbidity in Schistosoma haematobium infection

Urinary Bladder Schistosomiasis Mimicking Neoplasm: A Case Report

Schistosomiasis is a neglected disease that is prevalent in tropical and subtropical areas. A 20-year-old woman presented to the emergency room with a history of right flank pain and lower abdominal discomfort for one day, which coincided with the onset of menses. The patient did not provide any history of premenstrual hematuria. The physical examination revealed right costovertebral angle tenderness and was otherwise unremarkable. The urinalysis demonstrated a mild increase in red and white blood cells and no ova or parasite. The blood test was normal, except for eosinophilia. A right pedunculated intraluminal urinary bladder mass was detected by the computerized axial tomographic scan and ultrasonography, and after the transurethral resection of the mass, the patient was diagnosed with urinary schistosomiasis. The patient received two doses of oral praziquantel of 1200 mg every 12 h for one day. The cure was confirmed with a one-month post-treatment follow-up that revealed a normal urine microscope and eosinophil count. The S. haematobium infection should be evaluated as a possible cause of urinary bladder lesion in those who have travelled or lived in endemic areas.

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

Previous population-based studies have examined treatment impact on Schistosoma-associated urinary tract disease among children, but much less is known about longer-term treatment benefits for affected adult populations in areas where risk of recurrent infection is high. In communities in Msambweni, along the Kenya coast, we identified, using a portable ultrasound, 77 adults (aged 17-85) with moderate-to-severe obstructive uropathy or bladder disease due to Schistosoma haematobium. Treatment response was assessed by repeat ultrasound 1-2 years after praziquantel (PZQ) therapy and compared with interval changes among age- and sex-matched infected/treated control subjects who did not have urinary tract abnormalities at the time of initial examination. Of the 77 affected adults, 62 (81%) had improvement in bladder and/or kidney scores after treatment, 14 (18%) had no change, and one (1.3%) had progression of disease. Of the 77 controls, 75 (97%) remained disease free by ultrasound, while two (3%) had apparent progression with abnormal findings on follow-up examination. We conclude that PZQ therapy for S. haematobium is effective in significantly reducing urinary tract morbidity from urogenital schistosomiasis among adult age groups, and affected adults stand to benefit from inclusion in mass treatment campaigns.

Micro-geographical heterogeneity in Schistosoma mansoni and S. haematobium infection and morbidity in a co-endemic community in northern Senegal

BACKGROUND

Schistosoma mansoni and S. haematobium are co-endemic in many areas in Africa. Yet, little is known about the micro-geographical distribution of these two infections or associated disease within such foci. Such knowledge could give important insights into the drivers of infection and disease and as such better tailor schistosomiasis control and elimination efforts.

METHODOLOGY

In a co-endemic farming community in northern Senegal (346 children (0-19 y) and 253 adults (20-85 y); n = 599 in total), we studied the spatial distribution of S. mansoni and S. haematobium single and mixed infections (by microscopy), S. mansoni-specific hepatic fibrosis, S. haematobium-specific urinary tract morbidity (by ultrasound) and water contact behavior (by questionnaire). The Kulldorff's scan statistic was used to detect spatial clusters of infection and morbidity, adjusted for the spatial distribution of gender and age.

PRINCIPAL FINDINGS

Schistosoma mansoni and S. haematobium infection densities clustered in different sections of the community (p = 0.002 and p = 0.023, respectively), possibly related to heterogeneities in the use of different water contact sites. While the distribution of urinary tract morbidity was homogeneous, a strong geospatial cluster was found for severe hepatic fibrosis (p = 0.001). Particularly those people living adjacent to the most frequently used water contact site were more at risk for more advanced morbidity (RR = 6.3; p = 0.043).

CONCLUSIONS/SIGNIFICANCE

Schistosoma infection and associated disease showed important micro-geographical heterogeneities with divergent patterns for S. mansoni and S. haematobium in this Senegalese community. Further in depth investigations are needed to confirm and explain our observations. The present study indicates that local geospatial patterns should be taken into account in both research and control of schistosomiasis. The observed extreme focality of schistosomiasis even at community level, suggests that current strategies may not suffice to move from morbidity control to elimination of schistosomiasis, and calls for less uniform measures at a finer scale.

Bladder morbidity and hepatic fibrosis in mixed Schistosoma haematobium and S. mansoni Infections: a population-wide study in Northern Senegal

Background

The global distribution map of schistosomiasis shows a large overlap of Schistosoma haematobium- and S. mansoni-endemic areas in Africa. Yet, little is known about the consequences of mixed Schistosoma infections for the human host. A recent study in two neighboring co-endemic communities in Senegal indicated that infection intensities of both species were higher in mixed than in single infections. Here, we investigated the relationship between mixed Schistosoma infections and morbidity in the same population. So far, this has only been studied in children.

Methods

Schistosoma infection was assessed by microscopy. Schistosoma-specific morbidity was assessed by ultrasound according to WHO guidelines. Multivariable logistic regression models were used to identify independent risk factors for morbidity.

Principal Findings

Complete parasitological and morbidity data were obtained from 403 individuals. Schistosoma haematobium-specific bladder morbidity was observed in 83% and S. mansoni-specific hepatic fibrosis in 27% of the participants. Bladder morbidity was positively associated with S. haematobium infection intensity (OR = 1.9 (95% CI 1.3–2.9) for a 10-fold increase in intensity). Moreover, people with mixed infections tended to have less bladder morbidity than those with single S. haematobium infections (OR = 0.3 (95% CI 0.1–1.1)). This effect appeared to be related to ectopic S. mansoni egg elimination in urine. Hepatic fibrosis on the other hand was not related to S. mansoni infection intensity (OR = 0.9 (95% CI 0.6–1.3)), nor to mixed infections (OR = 1.0 (95% CI 0.7–1.7)).

Conclusions/Significance

This is the first population-wide study on the relationship between mixed Schistosoma infections and morbidity. Mixed infections did not increase the risk of S. mansoni-associated morbidity. They even tended to reduce the risk of S. haematobium-associated morbidity, suggesting a protective effect of S. mansoni infection on bladder morbidity. These unexpected results may have important consequences for schistosomiasis control in co-endemic areas and warrant further investigation.

In the developing world, over 207 million people are infected with parasitic Schistosoma worms. Schistosoma haematobium and S. mansoni are the most abundant species in Africa and many people carry both. Yet, little is known about the consequences of such mixed infections. In general, S. haematobium affects the urinary tract of the host and S. mansoni the liver. Here, we investigated the effect of mixed Schistosoma infection on these health problems. We examined 403 people from northern Senegal for Schistosoma infections as well as for abnormalities of the urinary bladder and liver. Recently, we observed that people with mixed Schistosoma infections had generally higher infection intensities than those with single infections. The present study showed that abnormalities of the urinary bladder were more common in heavy than in light S. haematobium infections. Also, they were more common in single S. haematobium than in mixed infections. So far, only two studies have looked into the relationship between mixed Schistosoma infection and abnormalities of the bladder and liver, but only investigated children. Our findings suggest a possible protective effect of S. mansoni on bladder disease, in children as well as in adults. This may have important consequences for schistosomiasis control in co-endemic areas.

Ultrasound verification of bladder damage is associated with known biomarkers of bladder cancer in adults chronically infected with Schistosoma haematobium in Ghana

Long-term infection with urinary schistosomiasis has been associated with development of bladder cancer. However, bladder cancer is difficult to diagnose without invasive measures such as cystoscopy, thus there is little information on the epidemiological extent of the problem. Studies have been either case-control studies or case examinations in different geographical areas, estimating a schistosome-associated bladder cancer incidence of 3-4 cases per 100,000. We have used three indicators to examine the potential bladder cancer problem in an adult rural population in Ghana endemic for urinary schistosomiasis: (i) parasitological positivity; (ii) age prevalence of bladder damage from ultrasound scans; and (iii) detection of biomarkers associated with the presence of bladder cancer. Biomarkers were BLCA-4 test (urine) and nuclear morphometry or quantitative nuclear grading (QNG) of epithelial cells (urine sediment), which quantifies DNA ploidy status and nuclear morphometric descriptors, both of which can detect the presence of bladder cancer. Our data show an increasing association between age, severe bladder abnormalities and the occurrence of these biomarkers. Sixty-two of 73 cytopathology Papanicolaou-stained smears were seen to have squamous metaplasia. Although further investigations are needed, we suggest that schistosome-associated bladder cancer is an important public health concern in areas where Schistosoma haematobium is prevalent.

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.

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.

Schistosoma haematobium infection in children in Britain

OBJECTIVE

To highlight the existence of Schistosoma haematobium in certain ethnic minority groups in Britain and in English citizens who have recently visited Africa and the Middle East, so that general practitioners and paediatric nephrologists/urologists are aware of its occurrence and consider it among the differential diagnoses in children presenting with haematuria.

PATIENTS AND METHODS

Over a 2-year period, six consecutive boys (mean age 13.5 years, range 8-15) presented with haematuria and were subsequently diagnosed to be infected with S. haematobium. All patients were from Africa and had recently visited their native country. There had all reported paddling in freshwater lakes and streams.

RESULTS

Dysuria and haematuria was noted 2-3 months after the infection. Terminal urine samples taken after exercise at midday were positive for S. haematobium ova. Praziquantel anti-schistosomal chemotherapy was effective in treating the infection.

CONCLUSION

S. haematobium infection is treatable in the early stages and the changes are reversible before the development of fibrotic lesions, which may result in anatomical obstruction. A terminal urine sample taken at midday after exercise was diagnostic in showing Schistosoma ova in all cases. This infection must be considered in the differential diagnoses of haematuria in some ethnic minority British citizens and in those Britons who have visited Africa or the Middle East in the recent past.