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.

Prevalence and factors associated with urogenital schistosomiasis among primary school children in barrage, Magba sub-division of Cameroon

BACKGROUND

The purpose of this study was to determine the prevalence and intensity as well as the factors associated with urogenital schistosomiasis (US) in Barrage, a rural community around the Mape΄ dam, in the West region of Cameroon not previously documented for transmission.

METHODS

In this cross sectional parasitological survey, 382 children were enrolled from three primary schools in the study area between March and May 2016. A semi-structured questionnaire was used to collect information on demographics, clinical and predisposing factors. The syringe filtration technique was used to analyse urine samples. Samples with visible or gross haematuria were recorded prior to filtration. The Pearson chi-square, the student T-test and logistic regression were all performed as part of the statistical analyses.

RESULTS

The overall prevalence of US was 41.1% (95% CI: 36.1-46.2). Infection was more common in children below 10 years (p = 0.009), in males (p = 0.029), and in children who frequently come into contact with water from the dam (p < 0.001). Furthermore, US was more common in children attending Ecole Public (EP) Manbonko Bord (81.1%, p < 0.001) which is very close to the dam and in children from a fishing background (80.9%, p < 0.001). On the contrary, knowledge about schistosomiasis was not observed to be associated with prevalence. In this study, the intensity of infection was observed to be higher in children below 10 years (p < 0.001), in males (p = 0.001), and in children attending EP Manbonko Bord (p < 0.001). The intensity of infection was also highest in children presenting with haematuria (p < 0.001). Frequent contact with water from the dam and having parents whose occupation was fishing were identified as the associated factors for US.

CONCLUSION

A high prevalence of US was observed in school-aged children in the study area especially in those attending EP Manbonko Bord. Limiting contact with water from the dam, control of the snail intermediate host, provision of portable water and mass treatment of the entire population are proposed as some of the measures to reduce and eventually eliminate transmission in the area.

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.

Urinary estrogen metabolites and self-reported infertility in women infected with Schistosoma haematobium

BACKGROUND

Schistosomiasis is a neglected tropical disease, endemic in 76 countries, that afflicts more than 240 million people. The impact of schistosomiasis on infertility may be underestimated according to recent literature. Extracts of Schistosoma haematobium include estrogen-like metabolites termed catechol-estrogens that down regulate estrogen receptors alpha and beta in estrogen responsive cells. In addition, schistosome derived catechol-estrogens induce genotoxicity that result in estrogen-DNA adducts. These catechol estrogens and the catechol-estrogen-DNA adducts can be isolated from sera of people infected with S. haematobium. The aim of this study was to study infertility in females infected with S. haematobium and its association with the presence of schistosome-derived catechol-estrogens.

METHODOLOGY/PRINCIPAL FINDINGS

A cross-sectional study was undertaken of female residents of a region in Bengo province, Angola, endemic for schistosomiasis haematobia. Ninety-three women and girls, aged from two (parents interviewed) to 94 years were interviewed on present and previous urinary, urogenital and gynecological symptoms and complaints. Urine was collected from the participants for egg-based parasitological assessment of schistosome infection, and for liquid chromatography diode array detection electron spray ionization mass spectrometry (LC/UV-DAD/ESI-MSn) to investigate estrogen metabolites in the urine. Novel estrogen-like metabolites, potentially of schistosome origin, were detected in the urine of participants who were positive for eggs of S. haematobium, but not detected in urines negative for S. haematobium eggs. The catechol-estrogens/ DNA adducts were significantly associated with schistosomiasis (OR 3.35; 95% CI 2.32-4.84; P≤0.001). In addition, presence of these metabolites was positively associated with infertility (OR 4.33; 95% CI 1.13-16.70; P≤0.05).

CONCLUSIONS/SIGNIFICANCE

Estrogen metabolites occur widely in diverse metabolic pathways. In view of the statistically significant association between catechol-estrogens/ DNA adducts and self-reported infertility, we propose that an estrogen-DNA adduct mediated pathway in S. haematobium-induced ovarian hormonal deregulation could be involved. In addition, the catechol-estrogens/ DNA adducts described here represent potential biomarkers for schistosomiasis haematobia.

Risk factors for Schistosoma haematobium infection and morbidity in two villages with different transmission patterns in Niger

A better control of major neglected tropical diseases such as schistosomiasis is urgently needed to reduce their impact on public health in developing countries. To optimize the efficiency of intervention campaigns, we assessed the influence of individual human factors on the level of Schistosoma haematobium infection and morbidity in a typical Sahelian country (Niger). Random samples of 246 and 257 individuals were selected from general census in two villages with distinct patterns of schistosome transmission. One village (Lossa) is located in an area of perennial transmission whereas transmission is seasonal in the other village (Tara). Despite comparable levels of both egg excretion and lower tract pathology in the two villages, the inhabitants of Lossa had a higher risk (OR: 2.1, 95% CI: 1.1-3.9) of developing upper tract lesions compared to those living in Tara. In both villages, bladder lesions were more serious in males than in females. Children between 7 and 15 years old were the most at risk to experience heavy infections (OR: 3.4, 95% CI: 2.1-5.7), bladder (OR: 4.5, 95% CI: 2.6-7.8) and upper tract (OR: 10.4, 95% CI: 2.4-45.0) lesions, independently of gender and village. These results confirm that targeted intervention campaigns should include foci regardless of their schistosome transmission pattern and focus on the school-aged population.

Surgical pathology of schistosomiasis

Schistosomiasis remains an important health problem in many tropical countries and is being seen with increasing frequency in immigrant populations and tourists in developed countries. The pattern of organ involvement and clinical presentation of schistosomiasis in 80 patients (male: female, 9:1) during a five-year period (2001-2005) was examined from archival histopathology records. The urinary bladder was the most common organ affected [50 (62.5%)]. Gastrointestinal, male and female genital schistosomiasis were detected in 12 (15%), eight (10%) and five (6.1%) cases, respectively. Hematuria was the most common presenting symptom [34 (42.5%)], and bladder cancer was the only malignancy found to be associated with the infection. A high clinical index of suspicion usually allows for a preoperative diagnosis where indicated and avoidance of radical surgery. While research for the development of an effective vaccine continues, a plea is made for the expansion of multinational control programs in sub-Saharan Africa.

Urinary tract pathology in Schistosoma haematobium infected rural Nigerians

Parasitological investigation assessing the ova of Schistosoma haematobium in the urine of 138 volunteers in Ihieve-Ogben, Edo State, Nigeria revealed 43 positive results (31.2%). Children had a higher prevalence of urinary schistosomiasis 30 (41.1%) than their adult counterparts 13 (20.0%) and this difference was statistically significant (t = 8.89, p > 0.01). More volunteers had light intensity of infection 27 (19.6%) than heavy infection 16 (11.6%) and this difference was statistically significant (chi2 = 22.90, p>0.05). Ultrasonographic investigations carried out on these 43 S. haematobium infected volunteers revealed ten pathological conditions, including abnormal wall thickness 24 (55.8%), abnormal shape 30 (69.8%), irregular bladder wall 12 (27.9%), masses 10 (23.3%), pseudopolyps 2 (4.7%), echogenic particles 30 (69.8%), residual volume 12 (27.9%), calcifications 24 (55.8%), hydroureter 10 (23.3%) and hydronephrosis 8 (18.6%) when compared to control subjects which lacked bladder and kidney abnormalities. These pathological conditions were slightly more common in the volunteers with heavy infection than those with light infection, but this difference was not statistically significant (t = -2.19, p < 0.02). More pathological conditions were found in children than in adults; this finding was statistically significant (t = 3.23, p > 0.03). Hydronephrosis and hydroureter were not found in the volunteers with light intensity of infection.

Prevalence of schistomasiasis lesions detected by ultrasonography in children in Molodo, Mali

AIM

To study schistomasiasis infection in school children in Molodo, an irrigated rice growing region of Mali, by determining the prevalence of schistomasiasis and lesions identified by ultrasonography among children living in this region.

METHODS

This cross sectional study included 346 children aged 7 to 14 years selected at random from five schools in Molodo. We tested for hematuria using urine dipsticks and searched for Schistosoma haematobium eggs in urine and S. mansoni eggs in stools. Ultrasonography of the liver, spleen and urinary tract was performed.

RESULTS

The prevalences of Schistosoma haematobium and S. mansoni infection were 72% (range: 66.9-76.6%) and 68.2% (range: 60.9-71.2%) respectively; 55.1% of the children had co-infection. Ultrasonography of the urinary tract revealed an irregular bladder wall as the most frequent abnormality (3.4% of children). Abdominal ultrasonography demonstrated type B hepatic fibrosis in four children (1.1%), type C in one (0.3%) and type D in one (0.3%).

CONCLUSION

Few schistosomiasis lesions were detected by ultrasonography compared with the prevalence of S. haematobium and S. mansoni infections. This observation is probably related to mass treatment programs conducted during a national anti-schistosomiasis program.

Immunoglobulin classes (IgG, IgA and IgM) and acute phase proteins in pregnant women with urinary schistosomiasis

BACKGROUND

S. haematobium have been implicated in female genital schistosomiasis (FGS), ectopic pregnancy and infertility. The presence of schistosome eggs in urine has been reported to correlate with FGS but host immune response in FGS is yet to be determined. This gap in knowledge is addressed by this study.

MATERIALS AND METHODS

Serum levels of three immunoglobulin classes (IgG, IgA and IgM) and three acute phase proteins (transferrin, alpha 2-macroglobulin, and haptoglobin) were determined by using single radial immunodiffusion technique in one hundred and eight Nigerian women aged between 15 and 30 years. They were made up of thirty pregnant women with urinary schistosomiasis (P+USS), thirty-six pregnant women without USS (P-USS), eighteen non-pregnant women with USS (NP+USS) and twenty-four healthy non-pregnant women without urinary schistosomiasis (NP-USS).

RESULTS AND CONCLUSIONS

IgG, IgA and IgM were significantly raised in pregnant women with urinary schistosomiasis compared with non-pregnant women without urinary schistosomiasis (p < 0.01 in each case). The level of transferrin was significantly increased in non-pregnant subjects with urinary schistosomiasis compared with non-pregnant women without urinary schistosomiasis (p <0.01) suggesting the possibility of iron deficiency in these subjects. Alpha-2 macroglobulin was significantly elevated in pregnant subjects with urinary schistosomiasis compared with non-USS subjects, while the mean serum haptoglobin level was significantly higher in pregnant women without urinary schistosomiasis compared to pregnant subjects with urinary schistosomiasis. The results indicate that USS or pregnancy changes different aspects of humoral immunity, thus the co-existence of pregnancy and S. haematobium infection may influence each other.

Urinary schistosomiasis in Zimbabwean school children: predictors of morbidity

BACKGROUND

The morbid effects of urinary bilharziasis are becoming more evident with the advent of sophisticated diagnostics such as ultrasound. However, such diagnosis of Schistosoma haematobium morbidity is often hampered by lack of funds, proper equipment, or training.

OBJECTIVE

We performed a cross-sectional investigation of schoolchildren in a highly endemic area of east central Zimbabwe in order to assess the utility of a number of simple clinical indicators to predict Schistosoma haematobium morbidity.

METHODS

Prevalence and intensity of S. haematobium infection was determined in 551 schoolchildren, with ultrasound examination of the kidneys and bladder performed on 222. The association of a number of demographic, parasitological, and clinical parameters with clinical outcome was evaluated.

RESULTS

Overall, 60% of the children were infected with S. haematobium . Although lacking specificity, proteinuria and parasite eggs count best predicted bladder pathology. Presence of kidney dilation was associated with fatigue and pain upon urination, but these variables were not very sensitive.

CONCLUSIONS

None of the variables assessed were ideal predictors of morbidity. However, the results suggest that a combination of inexpensive, simple indicators may allow for improved targeting of S. haematobium treatment to those with severe morbidity and better monitoring of the progress of control campaigns when more expensive diagnostic methods are not available.

Ultrasound monitoring of structural urinary tract disease in Schistosoma haematobium infection

A major advance in our understanding of the natural history of Schistosoma haematobium-related morbidity has come through the introduction of the portable ultrasound machines for non-invasive examination of the kidneys and bladder. With the use of generators or battery packs to supply power in non-clinical field settings, and with the use of instant photography or miniaturized thermal printers to record permanent images, it is possible to examine scores of individuals in endemic communities every day. Broad-based ultrasound screening has allowed better definition of age-specific disease risks in urinary schistosomiasis. Results indicate that urinary tract abnormalities are common (18% overall prevalence) in S. haematobium transmission areas, with a 2-4% risk of either severe bladder abnormality or advanced ureteral obstruction. In longitudinal surveys, ultrasound studies have shown that praziquantel and metrifonate therapy are rapidly effective in reversing urinary tract abnormalities among children. The benefits of treating adults are less well known, but research in progress should help to define this issue. Similarly, the prognosis of specific ultrasound findings needs to be clarified, and the ease of sonographic examination will make such long-term follow-up studies feasible. In summary, the painless, quick, and reproducible ultrasound examination has become an essential tool in the study of urinary schistosomiasis.

Morphological features and organ distribution of schistosomal infection

A total of 74 histologically diagnosed cases of schistosomiasis involving various organs and tissues were reported in the Department of Pathology of the University of Ilorin Teaching Hospital, Ilorin between January 1979 and December 1997. While some of the cases were incidental discoveries, others were the primary causes of patients' clinical problems such as infertility. The ages of patients in this study were relatively higher than the usual childhood or adolescence wherein schistosomiasis is commonest and this is thought to be due to the longer duration required for morphological changes to be established in tissues. A case of urinary bladder schistosomiasis with squamous cell carcinoma was found in a 55-year old man and this lends support to the claim that schistosomiasis of the urinary bladder may predispose to cancer in the organ. Findings in this study underscore the need for high index of suspicion in endemic areas wherein histological examination of appropriate tissue may be all that is needed in what otherwise appears to be a diagnostic enigma.

[The distribution of Phyllodistomum umblae and Phyllodistomum folium (Trematoda: Gorgoderidae) in the excretory system of fishes]

It is shown, that the distribution of Phyllodistomum umblae in the excretory system of all investigated species of salmonids has a principal similarity. The distribution of P. umblae in the excretory system of the Siberian dace and the Siberian roach is distinguished from that of P. folium.

Schistosoma haematobium infection in Egyptian schoolchildren: demonstration of both hepatic and urinary tract morbidity by ultrasonography

Parasitological, clinical and ultrasonographical studies were performed upon 422 schoolchildren aged 12-16 years living in a village in the Fayoum where Schistosoma haematobium, but not S. mansoni, was transmitted. Over half of the children gave a history of receiving praziquantel therapy during the preceding 2 years. Symptoms (e.g., haematuria, burning micturition), signs (e.g., hepatomegaly, splenomegaly) and urinary findings (e.g., haematuria, proteinuria) correlated better with the presence and intensity of S. haematobium infection after correcting for this variable. Renal obstructive lesions detected by ultrasound were 2 and 3 times as common in those with moderate and heavy infections as in those with no or light infections, and urinary bladder wall lesions were far more frequent in those with moderate and heavy infections. A mild grade of periportal fibrosis, hepatomegaly and splenomegaly were present in some children in all groups. However, the prevalence of splenomegaly correlated directly with the intensity of infection; liver lesions occurred much more frequently in children with infection or a history of treated infection than in non-infected children denying recent treatment; and no child had hepatomegaly or splenomegaly in the absence of periportal fibrosis.

Trypanosoma cruzi: explant organ cultures from mice with chronic Chagas' disease

Explants of 13 different organs obtained from C3H/HEN, Swiss-Webster, and C57Bl/6 mice chronically infected with Trypanosoma cruzi (Y strain) were cocultivated with mouse embryo fibroblasts to determine the organs that contain T. cruzi during the chronic infection. Explant cultures frequently yielded T. cruzi as late as 12 months after infection. Spleen and skeletal muscle were most frequently positive; heart cultures were rarely positive in any mouse strain. C3H/HEN mice had significantly more cultures positive than Swiss-Webster mice, as expected from relative susceptibility of C3H/HEN mice to acute infection. In contrast, C57Bl/6 mice, relatively resistant to acute infection, had significantly more cultures positive at 12 months of infection than Swiss-Webster mice. Also, C57Bl/6 mice had a significant increase in the number of positive cultures at 12 months of infection compared to 6 months of infection. These results show that organisms can be recovered routinely from some tissues during the chronic infection, that murine susceptibility to infection should differentiate between acute and chronic infection, and that C57Bl/6 mice may lose control of infection during the chronic infection.

Urinary tract lesions due to Schistosoma haematobium infection assessed by ultrasonography in a community based study in Niger

The comparative prevalences of urinary tract lesions in 2 villages where urinary schistosomiasis was endemic and in a control village free from infection were assessed by ultrasonography. Of the 822 residents greater than 4 years of age in the first village (Sébéri) where the prevalence of infection was 57%, 279 were examined by ultrasonography. The prevalence of bladder lesions was 71% in those 5-14 years of age, 57% among adult men, and 24% among women in this endemic village, compared to 10%, 16%, and 6%, respectively, in the control village. Renal lesions were infrequent among adults and there was no significant difference in the rates between Sébéri and the control village. Among children, moderate hydronephrosis was absent in the control village, but was observed in 19% of the boys 5-14 years of age and 2% of the girls 5-14 years of age in Sébéri. Sixty schoolchildren of the second endemic village with urinary egg counts greater than or equal to 100 eggs/10 ml of urine were examined by ultrasonography. The overall prevalence and the severity of bladder lesions in the 2 endemic villages were significantly related to the urinary egg count.

Patterns of Schistosoma haematobium egg distribution in the human lower urinary tract. I. Noncancerous lower urinary tracts

Schistosoma haematobium egg burdens (eggs/g of tissue) of 17 anatomic segments of lower urinary tracts from 32 unselected Egyptian autopsies have been determined by tissue digestion and replicate counts of aliquots of the digestate. There were three anatomic patterns of egg distribution in these lower urinary tracts: apical, basal and diffuse. Regression of egg burdens of each of the anatomic segments as the dependent variable against egg burdens of the entire lower urinary burden yielded a good fit for 15 of 17 of these segments. Statistical analyses revealed that many of these equations for discrete anatomic segments can be combined, generally giving one equation for anatomic regions which are in continuity, indicating that the female worm lives and oviposits in specified venous plexes. These equations also suggest that there are differences in the rates, duration and onset of egg accumulation which may be responsible for schistosomal obstructive uropathy as a cause of death in fairly young individuals.

Bladder calcification and obstructive uropathy in a gibbon infected with Schistosoma haematobium

A gibbon was repeatedly exposed to Schistosoma haematobium infection and was followed for 68 months after the first exposure. Severe obstructive uropathy and calcification of the bladder and ureters were found despite the fact that mean excretion of eggs in the urine averaged 167 eggs per day and never exceeded 400 eggs per day.

The pathology, pathobiology and pathogenesis of schistosomiasis

Although the general pathology of schistosomiasis has been well understood for more than 70 years, it is only recently that it has been possible to analyse the disease at the molecular level and to understand the relationship between the number of parasites in an infected individual and the appearance of overt disease.