Morbidity assessment in urinary schistosomiasis infection through ultrasonography and measurement of eosinophil cationic protein (ECP) in urine

An update on non-invasive urine diagnostics for human-infecting parasitic helminths: what more could be done and how?

Reliable diagnosis of human helminth infection(s) is essential for ongoing disease surveillance and disease elimination. Current WHO-recommended diagnostic assays are unreliable in low-endemic near-elimination settings and typically involve the invasive, onerous and potentially hazardous sampling of bodily fluids such as stool and blood, as well as tissue via biopsy. In contrast, diagnosis by use of non-invasive urine sampling is generally painless, more convenient and low risk. It negates the need for specialist staff, can usually be obtained immediately upon request and is better accepted by patients. In some instances, urine-based diagnostic assays have also been shown to provide a more reliable diagnosis of infection when compared to traditional methods that require alternative and more invasive bodily samples, particularly in low-endemicity settings. Given these relative benefits, we identify and review current research literature to evaluate whether non-invasive urine sampling is currently exploited to its full potential in the development of diagnostic tools for human helminthiases. Though further development, assessment and validation are needed before their routine use in control programmes, low-cost, rapid and reliable assays capable of detecting transrenal helminth-derived antigens and cell-free DNA show excellent promise for future use at the point-of-care in high-, medium- and even low-endemicity elimination settings.

The Responses of the Ribonuclease A Superfamily to Urinary Tract Infection

The lower urinary tract is routinely exposed to microbes residing in the gastrointestinal tract, yet the urothelium resists invasive infections by gut microorganisms. This infection resistance is attributed to innate defenses in the bladder urothelium, kidney epithelium, and resident or circulating immune cells. In recent years, surmounting evidence suggests that these cell types produce and secrete soluble host defense peptides, including members of the Ribonuclease (RNase) A Superfamily, to combat invasive bacterial challenge. While some of these peptides, including RNase 4 and RNase 7, are abundantly produced by epithelial cells, the expression of others, like RNase 3 and RNase 6, increase at infection sites with immune cell recruitment. The objective of this mini-review is to highlight recent evidence showing the biological importance and responses of RNase A Superfamily members to infection in the kidney and bladder.

Protocol and baseline data for a multi-year cohort study of the effects of different mass drug treatment approaches on functional morbidities from schistosomiasis in four African countries

BACKGROUND

The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) focus is on randomized trials of different approaches to mass drug administration (MDA) in endemic countries in Africa. Because their studies provided an opportunity to evaluate the effects of mass treatment on Schistosoma-associated morbidity, nested cohort studies were developed within SCORE's intervention trials to monitor changes in a suite of schistosomiasis disease outcomes. This paper describes the process SCORE used to select markers for prospective monitoring and the baseline prevalence of these morbidities in four parallel cohort studies.

METHODS

In July 2009, SCORE hosted a discussion of the potential impact of MDA on morbidities due to Schistosoma infection that might be measured in the context of multi-year control. Candidate markers were reviewed and selected for study implementation. Baseline data were then collected from cohorts of children in four country studies: two in high endemic S. mansoni sites (Kenya and Tanzania), and two in high endemic S. haematobium sites (Niger and Mozambique), these cohorts to be followed prospectively over 5 years.

RESULTS

At baseline, 62% of children in the S. mansoni sites had detectable eggs in their stool, and 10% had heavy infections (≥ 400 eggs/g feces). Heavy S. mansoni infections were found to be associated with increased baseline risk of anemia, although children with moderate or heavy intensity infections had lower risk of physical wasting. Prevalence of egg-positive infection in the combined S. haematobium cohorts was 27%, with 5% of individuals having heavy infection (≥50 eggs/10 mL urine). At baseline, light intensity S. haematobium infection was associated with anemia and with lower scores in the social domain of health-related quality-of-life (HRQoL) assessed by Pediatric Quality of Life Inventory.

CONCLUSIONS

Our consensus on practical markers of Schistosoma-associated morbidity indicated that height, weight, hemoglobin, exercise tolerance, HRQoL, and ultrasound abnormalities could be used as reference points for gauging treatment impact. Data collected over five years of program implementation will provide guidance for future evaluation of morbidity control in areas endemic for schistosomiasis.

TRIAL REGISTRATION

These cohort studies are registered and performed in conjunction with the International Standard Randomised Controlled Trial Registry trials ISRCTN16755535 , ISRCTN14117624 , ISRCTN95819193 , and ISRCTN32045736 .

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.

Urinary schistosomiasis

Schistosomiasis is the second most common socio-economically devastating parasitic disease after malaria, affecting about 240 million residents of developing countries. In Africa, it predominantly manifests as urogenital disease, and the main infective agent is Schistosoma hematobium. Endemicity is propagated by poor socio-economic status and environmental degradation due to rapid urbanization. Recreational swimming is a potent medium for the spread of disease in children and adolescents. Most affected individuals are asymptomatic. The male and female worms are equipped with an extraordinary capacity for immune evasion and are able to co-habit for several decades within the pelvic venous plexus. Eggs deposited in the bladder wall resist elimination by type 1 T lymphocytes. Instead, they are sustained by pro-fibrogenic encapsulation (as modulated by type 2 helper cells). Progressive bladder disease results in obstructive uropathy and predisposes to (mostly) squamous cell carcinoma. Schistosomal glomerulopathy manifests as a clinical spectrum of asymptomatic proteinuria, nephrosis and/or nephritic syndrome. Findings on renal biopsy may be influenced by co-morbidity with Salmonella bacteria, amyloidosis and hepatitis C infection. Potentially fatal Katayama fever and spinal radiculopathy may ensue in tourists visiting an endemic zone. Early detection by urine microscopy is hampered by low urinary excretion rates of the parasite eggs. Although useful in travelers with newly acquired disease, the results of the serological antibody assay may be false positive in residents of an endemic zone. Cystoscopy, however, may be invaluable. Due to its safety, effectiveness and once-daily dosing, praziquantel is the drug of choice. An integrated approach that includes mass chemotherapy, environmental health programs and public health education is the most cost-effective preventive strategy.

Eosinophil granule proteins ECP and EPX as markers for a potential early-stage inflammatory lesion in female genital schistosomiasis (FGS)

BACKGROUND

Genital granulomas induced by Schistosoma haematobium eggs can manifest as different lesion types visible by colposcopy; rubbery papules (RP), homogenous sandy patches (HSP) and grainy sandy patches (GSP). Pronounced tissue eosinophilia is a candidate marker for active S. haematobium pathology, as viable schistosome egg granulomas often are eosinophil rich. Here it was investigated whether eosinophil granule proteins ECP (eosinophil cationic protein) and EPX (eosinophil protein-X) in urine and genital lavage can be used as markers for active FGS lesions.

METHODS

Uro-genital samples from 118 Malagasy women were analysed for ECP and EPX by standard sandwich avidin/biotin amplified ELISA.

PRINCIPAL FINDINGS

The women with RP lesions had significantly higher levels of ECP and EPX in both lavage and urine. Furthermore, women with RP lesions were significantly younger than those with GSP. This could indicate that RP lesions might be more recently established and thus represent an earlier inflammatory lesion stage.

CONCLUSION

ECP in genital lavage might be a future tool aiding the identification of FGS pathology at a stage where reversibility remains a possibility following praziquantel treatment.

Schistosoma mansoni in schoolchildren in a Madagascan highland school assessed by PCR and sedimentation microscopy and Bayesian estimation of sensitivities and specificities

Madagascar is an endemic area for schistosomiasis, but recent prevalence data are scarce. We investigated stool samples of 410 children aged 4-18 years from a combined primary and secondary school in a Madagascan highland village near Ambositra in order to assess the prevalence of Schistosoma mansoni using microscopy and real-time polymerase chain reaction (PCR). A high prevalence of S. mansoni of 77.1% was detected by PCR, while only 15.2% of microscopic examinations of sedimentation-enriched stools were positive. We estimated the sensitivity and specificity of stool sedimentation microscopy (19.7% and 98.8%) and of PCR (98.9% and 89.3%) using a Bayesian approach for two dependant tests in one population without a reference standard. Our Bayesian posterior estimate of the prevalence is 80.2%. Simple sedimentation technique misses about 4/5 of all PCR-confirmed infections and is insufficient to determine the prevalence of S. mansoni. A survey comparing PCR with a classical standard technique (KatoKatz) is desirable.

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.

A wake up call for urinary schistosomiasis: reconciling research effort with public health importance

This review considers the current status of urinary schistosomiasis, caused by infection with Schistosoma haematobium, and argues that greater research effort and focus are needed to improve understanding of this neglected tropical disease (NTD). The inappropriateness of relying solely on data concerning the much more extensively studied intestinal form of schistosomiasis caused by S. mansoni is highlighted. The current lack of genome and transcriptome information for S. haematobium is directly hindering further targeted research and must be quickly rectified. Recent molecular phylogenies caution the expectation of similarities between schistosome species and highlight the close relationships of species within the S. haematobium group. Treatment, current and prospective drugs and vaccines, together with diagnosis are considered, highlighting the differences associated with urinary schistosomiasis. This infection has a significant and specific impact on the urino-genital system and has a strong association with bladder cancer, leading to severe and chronic morbidity. There is a clear need for new clinical initiatives in this area to better quantify the disease burden. Furthermore, emerging associations with HIV and other pathogens need to be closely monitored. Research is urgently needed to improve current knowledge in order to develop the next generation of control tools.

Diagnostic dilemmas in helminthology: what tools to use and when?

Available data regarding the distribution, prevalence and severity of various diseases are based on the performance and operational characteristics of the diagnostic techniques applied; this is a fact that is particularly apparent in the study of helminth infections. An important lesson learnt from the efforts to rein in dracunculiasis, lymphatic filariasis and schistosomiasis is that the diagnostic approach needs to be changed as further progress is made towards control and ultimate elimination of the disease. This insight prompted the opinion piece presented here, which highlights diagnostic dilemmas in helminthology related to the stage of control achieved and sets out some research needs.

Semen quality in Schistosoma haematobium infected men in Madagascar

The seminal vesicles and the prostate are frequently affected by egg-induced inflammation in Schistosoma haematobium infected men. The objective of this study was to assess the semen quality in men with male genital schistosomiasis (MGS). The examination of the semen samples was performed in men aged 15 to 49 years living an S. haematobium endemic area in Madagascar prior to anti-schistosoma treatment with praziquantel and five months later. Men from the high endemic Sirama sugarcane plantation with positive egg excretion in the urine and circulating anodic antigen (CAA) present in serum (n=85) were compared to men (without egg excretion and no CAA) from the neighbouring low-endemic Mataipako village (n=57). The proportion of men with egg excretion in semen was significantly higher in Sirama than in Mataipako (53% versus 4%), whereas the median ejaculate volume was significantly lower in Sirama (1.8 ml versus 2.4 ml). There was no statistical difference in median spermatocyte counts and in the proportions of men detected with azoospermia. The mean apoptotic rate was 7.8% in a subgroup of 30 men from Sirama. A positive correlation was found between apoptotic rate and seminal eosinophil cationic protein (ECP) level (rho=0.560; P<0.001). At follow up, egg excretion and ECP level in semen declined significantly and were paralleled by a significant reduction in the apoptotic rate. The study suggests that S. haematobium infection is associated with sperm apoptosis and a reduced production of seminal fluid. Egg induced inflammation in the seminal vesicles and the prostate could be underlying mechanism for both observations.

Assessment of Schistosoma mansoni induced intestinal inflammation by means of eosinophil cationic protein, eosinophil protein X and myeloperoxidase before and after treatment with praziquantel

Faecal concentrations of eosinophil cationic protein (ECP), eosinophil protein X (EPX) and myeloperoxidase (MPO) were measured in extracts of stool samples obtained from a cohort of people (n=182) living in Bugoigo, a fishing community on the Eastern shore of Lake Albert, Buliisa District, in North Western Uganda where Schistosoma mansoni is endemic. Samples were collected before treatment and 5, 15, 20 and 52 weeks after treatment with praziquantel. Significantly increased levels of faecal ECP and EPX were found in S. mansoni infected individuals (n=155) compared to the levels found in stools from non-infected (n=27) (median values ECP: 11.3 microg/g vs. 5.9 microg/g, P=0.005, and EPX: 413.5 ng/g vs. 232.2 ng/g, P=0.045). An increased level of MPO was also found among the infected individuals compared to the non-infected 11.6 mu/g vs. 5.3 mu/g, P=0.07). Significant but weak correlations were found between faecal egg counts and faecal concentrations of ECP and EPX. Treatment with praziquantel induced a significant decline in both ECP and EPX, but only a non-significant reduction in faecal MPO. Following reinfection and despite of very low infection intensities, the protein levels increased significantly reaching the pre-treatment level (ECP and EPX) or levels significantly higher than the pre-treatment levels (MPO). This response pattern may imply a rebound effect during reinfection following treatment and resolution of immune regulatory immunosuppressive mechanisms in function during the chronic infection.

EAU guidelines for the management of urogenital schistosomiasis

More than 100 million people worldwide are affected by bilharziasis, caused by Schistosoma haematobium. For travellers precaution is most important. For the population in endemic areas, an integrated approach including health education is necessary. Effective pharmacologic treatment is available.

Schistosomiasis: from risk assessment to control

In this article, an account of some of the hot areas in schistosomiasis research is given, emphasizing what has been achieved during the past several years in impact assessment and identifying the research frontiers where further action is needed.

Schistosomiasis: a critical review

Precise data on epidemiology, morbidity, post-treatment resolution, reinfection, and resurgence of schistosomiasis could be helpful in establishing purposeful treatment plans for the disease in endemic populations. Here we give a concise overview of recent publications on bilharziasis. A main emphasis is placed on studies on the prevalence of schistosomiasis, partly including long term surveillance of morbidity following treatment with praziquantel. As genito-urinary schistosomiasis may be a risk factor for the spread of HIV, the involvement of the reproductive tract has become another focus in research on the disease. A novel diagnostic tool, eosinophil cationic protein (ECP), is proposed to correlate with the degree of inflammation of the genito-urinary tract.

Eosinophil granule proteins in serum and urine of patients with helminth infections and atopic dermatitis

Eosinophil cationic protein (ECP) and eosinophil-derived neurotoxin (EPX) are cytotoxic molecules involved in helminth infections and allergic reactions. Hitherto most clinical chemical studies have been concerned with the analysis of serum ECP in allergic diseases. The aim of this study was to examine whether serum as well as urine levels of these proteins are useful clinical chemical parameters in helminthiases and allergic diseases such as atopic dermatitis. Comparing these diseases under the same methodological conditions, levels of ECP and EPX were generally higher in helminthiases than in atopic dermatitis and non-helminth, non-allergic diseases. The highest levels of both proteins occurred in tropical worm diseases, in particular hookworm disease and onchocerciasis. When comparing helminthiases with allergic disorder, only hookworm disease (ECP and EPX) and onchocerciasis (EPX) exhibited significantly higher eosinophil cationic protein serum levels than atopic dermatitis. In patients with schistosomiasis mansoni and egg loads of > 1000-10 000 eggs/g stool (epg) EPX serum levels were significantly higher than in patients exhibiting loads < 1000 epg. Urinary analyses revealed only EPX to be present in measurable amounts. Levels of this protein were much higher in urine of patients with hookworm disease and onchocerciasis than in those with atopic dermatitis and in healthy controls. The results suggest that besides serum EPX, urinary EPX may be a useful clinical chemical parameter in eosinophilia of helminth and allergic aetiology.

Assessment of morbidity in Schistosoma haematobium infection: current methods and future tools

Recently, new potential tools for assessment of Schistosoma haematobium related morbidity have emerged. The tools are based on detection of S. haematobium egg antigens in urine or detection of eosinophil cationic protein (ECP) in urine, which may reflect the inflammatory response in the urinary tract. So far two markers have been assessed in long-term post treatment follow-up studies, allowing for an evaluation both before treatment and during regression and reappearance of infection and urinary tract morbidity. The results from these studies and the usefulness of the markers as morbidity assessment tools are discussed.