Schistosomiasis in Cross River State, Nigeria: 1. Prevalence and intensity of infection in Adim, Akamkpa Local Government Area

Mid-stream urine was randomly collected from 248 subjects in Adim. Blood and protein concentrations were determined semi-quantitatively using Combi-7 reagent strips. The urine samples were then processed and any ova of Schistosoma haematobium present were counted per 10 ml urine. Fresh stool samples were also randomly collected, processed and examined for S. masoni and other helminthic ova. The prevalence of S. haematobium in the area was 43.5% and this was found to be age-related but not sex-related. Mean egg count was 137.2 per 10 ml urine. Intense haematuria of 250 ery/microliters and proteinuria of 500 mg/dl accompanied the high egg counts. The stool examination showed no cases of Manson's schistosomiasis but polyparasitism with other intestinal helminths was common particularly among children under 10 years old. This is the first report of urinary schistosomiasis in this area and the high prevalence rate is consistent with the rice farming occupation of the natives of the area. The sensitive nature and the case of application of the reagent strips in determining heavy infections by measuring haematuria and proteinuria is once again confirmed.     

Genitourinary schistosomiasis among pre-primary schoolchildren in a rural community within the Cross River Basin, Nigeria

In Africa, most schistosomiasis control programmes defined the age 5-19 years as the target population for nationwide control through the school systems, excluding the under fives. A study was therefore undertaken to determine the prevalence and intensity of genitourinary schistosomiasis in children aged 0-5 years (pre-primary) in Adim, a rural and endemic community within the Cross River Basin, Nigeria. Of the 126 children examined, 25 (19.8%) were infected with Schistosoma haematobium, with no significant difference (P > 0.05) in infection rates between boys (21.1%) and girls (18.2%). Both prevalence and intensity of infection increased significantly (P 0.05) between intensity in boys (6.2 eggs/10 ml urine) and girls (5.6 eggs/10 ml urine). A total of 32.5 and 27.8% of the children had haematuria and proteinuria, respectively; it was not gender specific (P > 0.05). Six species of snail were encountered, with Bulinus globosus being the most abundant and widespread. The results of this study have shown that pre-primary schoolchildren are a source of transmission of schistosomiasis in endemic communities and should be integrated into any control intervention.     

The validity of haematuria in the community diagnosis of urinary schistosomiasis infections

The validity and reliability of haematuria when used as screening criteria in community diagnosis of urinary schistosomiasis is presented. Between May and July, 1998, 1173 persons were screened for haematuria and examined for the presence of eggs of Schistosoma haematobium in their urine from all participating households in the Ozitem area of Bende Local Government Area, Abia State, Nigeria. Haematuria showed a sensitivity rate of 41.0% and specificity of 82.0% when used to identify cases of urinary schistosomiasis. Some factors that influenced the validity of haematuria as a diagnostic criterion are discussed. The use of haematuria amongst subjects in the first twenty years of their life is recommended.     

The prevalence, intensity and clinical signs of urinary schistosomiasis in Imo state, Nigeria

Urine samples were assayed for urinary schistosomiasis in four local government areas (LGA) of Imo State, Nigeria between May 1998 and September 2000. A total of 3504 persons were sampled, with 880 (25.1%) being positive for urinary schistosomiasis, based on records of eggs of Schistosoma haematobium. The prevalence of S. haematobium infection differed in the various LGAs, with Oguta (38.9%) and Owerri-West (10.4%) showing the highest and the lowest values, respectively. Prevalence was higher in males (67.4%) than in females (32.6%) and in subjects 11-20 years of age (31.5%), while prevalence varied among different occupational groups, with farmers ranking the highest (41.6%). Visible haematuria was the predominant symptom (P<0.05). Of 880 persons positive for eggs of S. haematobium, 452 (51.4%) had visible haematuria, followed by suprapubic pains 214 (24.3%) and painful micturition 97 (11.0%). Although 367 (10. 5%) of the sampled subjects with eggs of S. haematobium showed no visible haematuria, 513 (14.6%) clearly demonstrated haematuria.     

Endemicity, focality and seasonality of transmission of human schistosomiasis in Amagunze Village, eastern Nigeria

The pattern of transmission of human schistosomiasis was studied in Amagunze Village, eastern Nigeria, during 1986-1987. The prevalence of Schistosoma haematobium in 119 schoolboys aged 5-12 years was 79%. The geometric mean of intensity of infection was 49 eggs/10 ml urine and the frequency of visible haematuria was 25.2%. No S. mansoni infections were demonstrated. A marked seasonality in population density of Bulinus truncatus, B. forskalii and Biomphalaria pfeifferi was demonstrated with reduced densities during the late rainy and early dry seasons. Schistosoma sp. infected B. truncatus were found in the late dry and early rainy seasons in 2 out of 7 major human water contact sites studied. Seasonality and focality of transmission of S. haematobium and its high endemicity in the area were thus demonstrated.     

Urinary schistosomiasis in southern Ghana: 1. Prevalence and morbidity assessment in three (defined) rural areas drained by the Densu river

Epidemiological studies on urinary schistosomiasis were carried out in eight villages in the Ga and Akuapem South districts in Ghana. Single urine samples were collected from individuals aged 5 years and above between 10.00 and 14.00 h. The samples were examined for the presence of Schistosoma haematobium eggs using a filtration technique. Indirect morbidity was determined as the presence of microhaematuria and proteinuria using reagent strips, and macrohaematuria was recorded with the naked eye. Out of the study population of 3912 subjects, 2562 (65.5%) submitted urine samples. The prevalence of a Schistosoma haematobium infection ranged between 54.8 and 60.0%. Infection rates increased by age with a peak in the 10-19 years category, and decreased with increasing age. Disease prevalence was higher in males aged 15 years and above in Areas 2 (Ntoaso and Sansami Amanfro) and 3 (Dom Faase, Papase, Chento and Gidi Kope), whereas it was higher among males aged 10 years and above in Area 1 (Ayikai Doblo and Akramaman). The intensity of infection was highest among children aged 10-14 years in most of the villages. More than half of egg-positive children in this age group had a heavy infection (100 eggs and above in 10 ml of urine). Although both egg-positive and egg-negative individuals manifested variable degrees of macro- or micro-haematuria, microhaematuria was more prevalent among egg-positives (chi(2)=918.5, d.f.=1, P<0.01). The degree of microhaematuria and proteinuria were significantly associated with the intensity of the infection. These results indicate a high transmission of disease in the study area.     

Schistosoma haematobium infections in preschool children from two rural communities in Ijebu East, south-western Nigeria

There is an urgent need for information on schistosomiasis in preschool children, who are often excluded in mass treatment programmes. The prevalence and intensity of Schistosoma haematobium infection were determined in preschool children aged ≤ 6 years in two rural communities in Ijebu East, south-western Nigeria. Two urine samples each were collected from 83 preschool children from the two communities, tested for microhaematuria using reagent strips and then processed and examined with a microscope for S. haematobium eggs. Focus group discussions on perceptions of the disease and water contact practices were held in the communities with their guardians, caregivers and preschool children, using an interview guide. The prevalence of S. haematobium in the two communities was 14 (16.9%), with no significant differences (P = 0.661) in infection rate between boys (18.4%) and girls (14.7%). Both prevalence and intensity of infection did not increase significantly with age in both Korede and Obada community. However, there were significant differences in prevalence of infection between the two communities (P = 0.035). There was no association (P = 0.750) between intensity in boys (0.176 eggs/10 ml urine) and girls (0.110 eggs/10 ml urine). Focal group discussions with guardians and caregivers revealed that preschool children acquired infection early in their lives through exposure to infected stream water by their mothers, while the older children visit the stream for playing, bathing and swimming. It has therefore become imperative for preschool children to be included in the planning of schistosomiasis intervention programmes as a means of reducing transmission.     

Urinary schistosomiasis on Pemba Island: low-cost diagnosis for control in a primary health care setting

In the 1970s and early 1980s indirect diagnosis of urinary schistosomiasis, using urinalysis reagent strips for proteinuria and haematuria, was proposed as a possible alternative to the more accurate but very time-consuming parasitological methods. The recent experience o f the Schistosomiasis Control Programme for Pemba Island, which used a combination of (1) observations o f grossly bloody urine specimens, (2) results from reagent strips for measuring haematuria, and (3) treatment with praziquantel, is the first large-scale example o f a simple, inexpensive and promising alternative for controlling the morbidity caused by this parasite.     

Parasitological and histopathological effects of immunosuppression in guinea-pigs (Cavia porcellus) experimentally infected with Schistosoma haematobium

The parasitological and histopathological effects of immunosuppression in guinea-pigs (Cavia porcellus) experimentally infected with Schistosoma haematobium were studied. A total of 16 guinea-pigs were divided into four groups (four per group): non-immunosuppressed, non-infected group (NN); immunosuppressed, non-infected group (IN); immunosuppressed, infected group (II); non-immunosuppressed, infected group (NI). The IN and II groups were immunosuppressed with 5?mg/kg prednisolone while the II and NI animals were infected with 200-300 S. haematobium cercariae. Excretion of eggs in urine/faeces, worm burden and histopathology of some vital organs of the guinea-pigs were studied. Eggs of S. haematobium were observed in the urine of the NI and II groups from 9 weeks post-infection and in faeces from 10 and 13 weeks post-infection for the NI and II groups, respectively. However, II animals excreted more viable eggs in urine and faeces than those of the NI group. Worm recovery at 14 weeks post-infection showed that NI and II guinea-pigs had more female worms than male worms and a greater proportion of worm recovery for NI animals was of immature worms. Significant differences (P?0.05). Histological changes, which were notably reactions to adult S. haematobium worms, were observed in the organs of the NI and II groups but these changes were seen more in the organs of the immunosuppressed, infected (II) than in the non-immunosuppressed, infected (NI) guinea-pigs. The results suggest that immunosuppression before infection increased worm survival and had a moderate effect on liver and bladder histology of S. haematobium infected guinea-pigs.     

Urinary red-cell morphology during exercise.

Midstream urine samples were examined by phase-contrast microscopy before and immediately after 48 subjects participated in a long-distance run. Minor abnormalities were found in six samples before exercise. Eighteen subjects developed proteinuria and five haematuria on dipstick testing after exercise. Forty-four subjects had increased urinary red-cell counts after exercise; of these, 33 had counts above the normal range (800/ml). In all subjects urinary red cells were dysmorphic both before and after exercise, indicating a glomerular source. Ten subjects developed red-cell casts and 42 showed an increase in hyaline and hyaline-granular casts after exercise. There were modest increases in urinary white-cell counts in 35 subjects but little change in urine pH or osmolality with exercise. This study confirms that urinary red-cell counts commonly increase appreciably after exercise. The dysmorphic appearance of the red cells together with the presence of red-cell casts indicates a glomerular source for this common form of exercise haematuria.     

Therapeutic failure of praziquantel in the treatment of Schistosoma haematobium infection in Brazilians returning from Africa

Several cases of therapeutic failure of praziquantel used for the treatment of urinary schistosomiasis have been reported. Alternative drugs, like niridazol and metrifonate, have shown a lower therapeutic effect and more side effects than praziquantel. Twenty-six Brazilian military men (median age of 29 years) with a positive urine parasitological exam who were part of a United Nation peace mission in Mozambique in 1994 were treated with 40 mg/kg body weight praziquantel, single dose. They swam in Licungo river (Mocuba city, Mozambique) during the weekends. After this, they presented haematuria, dysuria, polakiuria, and lumbar pain. Control cystoscopy examinations carried out between 6 and 24 months after each treatment (including two additional treatments at a minimum interval of 6 months) revealed the presence of viable eggs. Granulomas in the vesical submucosa were observed in 46.2% (12/26) of the individuals. A vesical biopsy confirmed the presence of granulomas in all of these patients and the presence of viable eggs in 34.3% (9/26) of individuals who no longer excreted eggs in urine. The eggs filled with miracidia showed characteristics of viability. Histopathological examination using different strains demonstrated therapeutic failure and the need for repeated treatment. In this study, we demonstrated a low efficacy of praziquantel in the treatment of schistosomiasis haematobia, and the necessity of the urinary bladder biopsy as criterion of cure.     

Schistosomiasis at Loum, Cameroun; Schistosoma haematobium, S. intercalatum and their natural hybrid.

A survey of 500 schoolchildren in Loum in 1968 revealed an overall infection rate of 54.2% with Schistosoma intercalatum and this was the only species of schistosome encountered. In 1972 a number of children were found to be passing schistosome eggs in their urine and these eggs ranged in shape and size from the forms characteristic for S. haematobium to those of S. intercalatum. Preliminary laboratory studies demonstrated that hybridisation between the two species was occurring. Subsequent field surveys showed that the snail hosts for the two parasites (B. rohlfsi for S. haematobium and B. forskali for S. intercalatum) were both present in the river Mbette and its tributaries in Loum and the distribution of the two snail species coincided closely with the distribution of the schistosomes in the human population. Detailed study of a small group of children passing hybrid eggs in their urine revealed that few of them were passing eggs in their faeces and that those eggs which were found in faeces were not viable. Analysis of schistosome egg-shape by plotting cumulative size-frequency data on probability paper demonstrated that the graph obtained from a natural hybrid series was different from that given by a known mixture of the two separate species. The hybrid series included a number of exceptionally large eggs resembling those of S. bovis but isolation of these eggs and subsequent laboratory passage of the parasites showed that they were part of the series and were not evidence of the presence of a third species. Hybridisation experiments in the laboratory showed that the cross S. haematobium male X S. intercalatum femal is fully viable but that the reverse mating is not successful, thus accounting for the failure of the faecal eggs recovered from children with hybrid infections. Histological results from laboratory passaged hybrids suggest that the Ziehl-positive staining reaction of the egg-shells of S. intercalatum may be a recessive character. The observations reported here indicate that S. haematobium has only recently become established in Loum and that it is, through introgressive hybridisation, replacing the indigenous S. intercalatum. A suggested explanation for the change in the parasite fauna is offered and this depends upon ecological changes resulting from forest clearance and agricultural development providing improved conditions for the spread of B. rohlfsi, the snail host for S. haematobium. It is suggested that, in contrast to recent reports on the spread of S. intercalatum, this species is in fact retreating and being replaced by S. haematobium in areas where forest clearance is taking place. In conclusion it is suggested that introgressive hybridisation of this kind may have been responsible for the evolution of certain characteristic local strains of African schistosomes.     

Melatonin and taurine reduce early glomerulopathy in diabetic rats

Oxidative stress occurs in diabetic patients and experimental models of diabetes. We examined whether two antioxidants, melatonin and taurine, can ameliorate diabetic nephropathy. Enhanced expression of glomerular TGF-beta1 and fibronectin mRNAs and proteinuria were employed as indices of diabetic nephropathy. Experimental diabetes was induced by intravenous injection of streptozotocin 50 mg/kg. Two days after streptozotocin, diabetic rats were assigned to one of the following groups: i) untreated; ii) melatonin supplement by 0.02% in drinking water; or iii) taurine supplement by 1% in drinking water. Four weeks after streptozotocin, diabetic rats (n = 6: plasma glucose 516+/-12 mg/dl) exhibited 6.1 fold increase in urinary protein excretion, 1.4 fold increase in glomerular TGF-beta1 mRNA, 1.7 fold increase in glomerular fibronectin mRNA, 2.2 fold increase in plasma lipid peroxides (LPO), and 44 fold increase in urinary LPO excretion above the values in control rats (n = 6: plasma glucose 188+/-14 mg/dl). Chronic administration of melatonin (n = 6) and taurine (n = 6) prevented increases in glomerular TGF-beta1 and fibronectin mRNAs and proteinuria without having effect on blood glucose. Both treatments reduced lipid peroxidation by nearly 50%. The present data demonstrate beneficial effects of melatonin and taurine on early changes in diabetic kidney and suggest that diabetic nephropathy associated with hyperglycemia is largely mediated by oxidative stress.     

Single dose oral treatment in urinary schistosomiasis: a double blind trial.

A double blind trial of three oral preparations given in single doses for the treatment of Schistosoma haematobium infection was carried out in schoolchildren; selection was biased towards those who excreted large quantities of eggs. Praziquantel 40 mg/kg was the most effective drug giving a greater than 97% reduction in egg output six months after treatment; combined treatment with niridazole 25 mg/kg and metrifonate 10 mg/kg gave a reduction of greater than 92% and metrifonate 10 mg/kg alone a reduction of greater than 86%. Fewer children continued to have moderate to heavy infections (excretion greater than 124 ova/10 ml urine) six months after treatment with praziquantel (5%) and the combined regimen (7%) than with metrifonate (16%). Though our findings show that praziquantel appears to be the most effective and convenient drug available for individuals with S haematobium infection, the combined regimen is a cheaper alternative for treatment where cost is important and parasitological cure not an essential objective.     

Haematuria Increases Progression of Advanced Proteinuric Kidney Disease

Background

Haematuria has been traditionally considered as a benign hallmark of some glomerular diseases; however new studies show that haematuria may decrease renal function.

Objective

To determine the influence of haematuria on the rate of chronic kidney disease (CKD) progression in 71 proteinuric patients with advanced CKD (baseline eGFR <30 mL/min) during 12 months of follow-up.

Results

The mean rate of decline in eGFR was higher in patients with both haematuria and proteinuria (haemoproteinuria, HP, n=31) than in patients with proteinuria alone (P patients, n=40) (-3.8±8.9 vs 0.9±9.5 mL/min/1.73m2/year, p<0.05, respectively). The deleterious effect of haematuria on rate of decline in eGFR was observed in patients <65 years (-6.8±9.9 (HP) vs. 0.1±11.7 (P) mL/min/1.73m2/year, p<0.05), but not in patients >65 years (-1.2±6.8 (HP) vs. 1.5±7.7 (P) mL/min/1.73m2/year). Furthermore, the harmful effect of haematuria on eGFR slope was found patients with proteinuria >0.5 g/24 h (-5.8±6.4 (HP) vs. -1.37± 7.9 (P) mL/min/1.73m2/year, p<0.05), whereas no significant differences were found in patients with proteinuria < 0.5 g/24 h (-0.62±7.4 (HP) vs. 3.4±11.1 (P) mL/min/1.73m2/year). Multivariate analysis reported that presence of haematuria was significantly and independently associated with eGFR deterioration after adjusting for traditional risk factors, including age, serum phosphate, mean proteinuria and mean serum PTH (β=-4.316, p=0.025).

Conclusions

The presence of haematuria is closely associated with a faster decrease in renal function in advanced proteinuric CKD patients, especially in younger CKD patients with high proteinuria levels; therefore this high risk subgroup of patients would benefit of intensive medical surveillance and treatment.     

Protein creatinine index and Albustix in assessment of proteinuria.

The protein creatinine index in early morning and random urine specimens was compared with the 24 hour urinary excretion of protein in normal subjects and outpatients with abnormal proteinuria. A protein creatinine index (defined as (mg protein/1 divided by creatinine mmol/1) times 10) below 125 in a random specimen excluded abnormal proteinuria, whereas an index of more than 136 indicated the presence of pathological proteinuria. The index for random specimens provided a useful semiquantitative assessment of the 24 hour excretion of protein (mg protein/24 hours), but the index for early morning specimens was less reliable. Errors with Albustix were partly due to intra and inter observer variations in the interpretation of the colour formed when compared with the chart provided. It is proposed that the protein creatinine index on random urine samples should be used to supplement dipsticks in screening for proteinuria in cases where misclassification would be serious.     

Urinary Schistosomiasis Treated with Sodium Antimony Tartrate—a Quantitative Evaluation

Seventeen Egyptian male farm-workers aged 8 to 27 years infected with Schistosoma haematobium were given twice-weekly intravenous injections of sodium antimony tartrate in a dose of 0.5 g. (30 mg.) per 15 kg. body weight for 12 injections. Bell''s egg-count technique was used to evaluate results on 24-hour urine collections before and at 1, 4, 8, and 12 weeks after treatment. Patients were considered to be cured only when there were no eggs in the urine when examined by the filtration-staining, miracidial-hatching, and 24-hour urinesediment examination methods.At the final follow-up 14 out of 17 patients were found not to be passing eggs in the urine—an 82% cure rate. The mean reduction in egg output in the remaining three patients was 99%. These results are superior to any reported for other antimony drugs.     

Evaluation of circulating cathodic antigen (CCA) strip for diagnosis of urinary schistosomiasis in Hassoba school children, Afar, Ethiopia

A total of 206 urine samples collected from Hassoba Elementary schoolchildren, Afar, Ethiopia, a low Schistosoma haematobium endemic setting, was diagnosed to evaluate the performance of CCA strip using double references, urine filtration technique and urinalysis dipstick (Combur 1.0 Test) that detect schistosome eggs and blood in urine, respectively. The former was used as a gold standard reference method. Sensitivity, specificity, positive and negative predictive values for the CCA were 52%, 63.8%, 56.7% and 59% respectively, with reference to urine filtration technique whereas these parameters were 50.4%, 62.4%, 55.6% and 57.5% respectively, with reference to Combur 10 Test. 47 S. haematobium egg-positive children were found negative by CCA strip while 38 egg-negative children were found positive by CCA strip. Moreover, among the pre-tests done in duplicate, inconsistent results were also recorded. Assays were also compared with regard to the cost of equipment and reagents, speed and simplicity of use. Though CCA strip was found to be rapid and could be performed with minimal training, it was found to be expensive (US $ 4.95 per test) to use it for large-scale field use even if its diagnostic value would have been satisfactory. Further development and standardization of the CCA strip are required for its applicability for field use. It is also recommended that its cost per strip should be substantially cut down if it is to be used in poor schistosomiasis endemic countries.     

Seasonal patterns in the transmission of Schistosoma haematobium in Attaouia, Morocco.

In the Attaouia area, the density of Bulinus truncatus (Audouin, 1827), was monitored monthly for a period of one year in correlation with weather variations. Snails were active throughout the year and particularly abundant at the end of spring and summer. Two snail generations were found to overlap. The infection rate of B. truncatus reached a maximum of 3.5% in the summer when human water contact was frequent. A selective survey conducted in the village of Lamyayha showed that the prevalence of infection with S. haematobium among the local population was 21.2% who were passing from 10 to 80 eggs per 10 ml of urine.     

Urinary schistosomiasis on Zanzibar: application of two novel assays for the detection of excreted albumin and haemoglobin in urine

As part of a urinary schistosomiasis control programme on Zanzibar, an aged cross-sectional survey of 305 children from three schools on Unguja was conducted to investigate the relationships between levels of excreted albumin and haemoglobin in urine and Schistosoma haematobium infection status. Diagnosis was determined by standard parasitological methods, dipstick reagents for microhaematuria, visual inspection for macrohaematuria as well as collection of case-history questionnaire data for self-diagnosis. Prevalence of infection as determined by parasitology was 53.9% and approximately, one quarter of the children examined were anaemic (<11 g dl(-1)). A statistically significant negative association of blood haemoglobin levels of boys and S. haematobium infection intensity status was observed (rs=-0.23, P=0.005). Through sensitivity analysis of urine-albumin values it was determined that a concentration of above >40 mg l(-1), as measured with the HemoCue urine-albumin photometer, had sensitivity, specificity, positive and negative predictive values of 0.90, 0.83, 0.86 and 0.89 respectively against 'gold-standard' parasitology. There was a clear association of reported pain upon micturition for children with elevated urine-albumin levels, with an odds ratio of 20 to 1. Levels of excreted blood in urine were quantified with the HemoCue Plasma/Low Hb photometer. However, dipsticks remain the method of choice for urine-haemoglobin of 0.1 g l(-1) and below. Urine parameters over a 24-h period were assessed in a small sub-sample. Reductions in both albumin and haemoglobin excretion were observed in 11 children 54 days after praziquantel treatment. It was concluded that these rapid, high-through-put, portable HemoCue assays could play a role in better describing and monitoring the occurrence, severity and evolution of urinary schistosomiasis disease. The urine-albumin assay has particular promise as a biochemical marker of S. haematobium induced kidney- and upper urinary tract-morbidity.