Showing papers on "Schistosoma haematobium published in 1999"

Helminth- and Bacillus Calmette-Guérin-Induced Immunity in Children Sensitized In Utero to Filariasis and Schistosomiasis

Abstract: Infants and children are routinely vaccinated with bacillus Calmette-Guerin (BCG) in areas of the world where worm infections are common. Because maternal helminth infection during pregnancy can sensitize the developing fetus, we studied whether this prenatal immunity persists in childhood and modifies the immune response to BCG. Children and newborns living in rural Kenya, where BCG is administered at birth and filariasis and schistosomiasis are endemic, were examined. T cells from 2- to 10-year-old children of mothers without filariasis or schistosomiasis produced 10-fold more IFN-γ in response to mycobacterial purified protein derivative than children of helminth-infected mothers ( p < 0.01). This relationship was restricted to purified protein derivative because maternal infection status did not correlate with filarial Ag-driven IL-2, IFN-γ, IL-4, or IL-5 responses by children. Prospective studies initiated at birth showed that helminth-specific T cell immunity acquired in utero is maintained until at least 10–14 mo of age in the absence of infection with either Wuchereria bancrofti or Schistosoma haematobium . Purified protein derivative-driven T cell IFN-γ production evaluated 10–14 mo after BCG vaccination was 26-fold higher for infants who were not sensitized to filariae or schistosomes in utero relative to subjects who experienced prenatal sensitization ( p < 0.01). These data indicate that helminth-specific immune responses acquired during gestation persist into childhood and that this prenatal sensitization biases T cell immunity induced by BCG vaccination away from type 1 IFN-γ responses associated with protection against mycobacterial infection.

Double-blind placebo-controlled study of concurrent administration of albendazole and praziquantel in schoolchildren with schistosomiasis and geohelminths.

Abstract: A double-blind placebo-controlled study of the concurrent administration of albendazole and praziquantel was conducted in >1500 children with high prevalences of geohelminths and schistosomiasis. The study sites were in China and the Philippines, including 2 strains of Schistosoma japonicum, and 2 different regions of Kenya, 1 each with endemic Schistosoma mansoni or Schistosoma haematobium. Neither medication affected the cure rate of the other. There was no difference between the side effect rate from albendazole or the double placebo. Praziquantel-treated children had more nausea, abdominal pain, and headache but these side effects were statistically more common in children with schistosomiasis, suggesting a strong influence of dying parasites. The subjects were followed for 6 months for changes in infection status, growth parameters, hemoglobin, and schistosomiasis morbidity. In all 4 sites, a significant 6-month increase in serum hemoglobin was observed in children who received praziquantel, strongly supporting population-based mass treatment.

Patterns of concurrent hookworm infection and schistosomiasis in schoolchildren in Tanzania.

Abstract: A cross-sectional study of 6897 schoolchildren in 59 out of the 155 primary schools in Magu District on the shores of Lake Victoria, Tanzania, was undertaken in 1997 to determine the prevalence of single- and multiple-species helminth infection. Schistosoma haematobium, hookworm (primarily Necator americanus) and S. mansoni were the most common helminth species infecting schoolchildren in the district. The prevalences of Ascaris lumbricoides and Trichuris trichiura were negligible (< 1%). Anaemia and stunting were highly prevalent and widespread. Hookworm and S. mansoni occurred more frequently in multiple infections with other helminths than as single-species infections, but triple-species infection was rare. Analysis of the frequency distribution of infection amongst schools showed that prevalences of S. haematobium and hookworm tended to be normally distributed, with medians 75% and 45%, respectively, while the distribution of S. mansoni was markedly skewed such that only 17% schools had a prevalence greater than 20%. An inverse association between S. mansoni and S. haematobium was observed. Geographical information system (GIS) analysis indicated that S. mansoni infection was highly prevalent only along the shore of Lake Victoria, whilst S. haematobium was homogeneously prevalent everywhere except the lakeshore. This pattern appears to reflect the distribution of schistosome species-specific snail intermediate hosts. The results imply that joint treatment for hookworm infection and schistosomiasis would be beneficial throughout the district.

Application of immunodiagnostic assays: detection of antibodies and circulating antigens in human schistosomiasis and correlation with clinical findings.

Abstract: In an initial cross-sectional survey, serum, urine, and stool samples were collected from 370 participants representing about 10% of the population (n = 4,438) in Behbeet village, 50 km south of Cairo, Egypt, an area well known to be endemic solely for Schistosoma haematobium. Diagnosis was approached in two parallel ways. The first approach, which simulated actual conditions in many endemic areas in Egypt, was based on physical examination and urine and stool microscopic analysis. The second approach was based on two advanced immunodiagnostic assay systems. One system detected antibodies to species-specific microsomal antigens, the other detected circulating schistosomal antigens. Microsomal antigens from S. haematobium and S. mansoni were used to detect antibodies in the Falcon assay screening test (FAST)-ELISA and the enzyme-linked immunoelectrotransfer blot (EITB). Circulating anodic antigen (CAA) and circulating cathodic antigen (CCA) were quantified in serum and urine samples in a sandwich ELISA using monoclonal antibodies. Parasitologically, the prevalence of S. haematobium was 7.01% in females and 25.82% in males, giving an overall prevalence of 15.8%. The combination of urine CCA and serum CAA for detecting circulating antigens and the combination of the S. haematobium adult worm microsomal antigens (HAMA) FAST-ELISA and the HAMA EITB for detecting antibodies significantly improved the sensitivity of detecting S. haematobium circulating antigens and antibodies. Also, including a medical examination as an integral part of field studies and correlating immunodiagnostic results with other clinical and investigational data allowed us to calculate an accurate estimation of S. haematobium prevalence in this area of low endemicity.

Host-parasite population genetics: a cross-sectional comparison of Bulinus globosus and Schistosoma haematobium.

Abstract: The genetic population structures of the freshwater snail Bulinus globosus and its trematode parasite Schistosoma haematobium from 8 river sites in the Zimbabwean highveld were compared using randomly amplified DNA (RAPD) markers. There was significant variability between snail populations collected at different sites, but schistosome populations only showed differentiation at a wider geographical scale (between 2 non-connected river systems). For snails, genetic distance was better correlated with proximity along rivers than absolute geographical separation. In contrast, schistosome genetic distance was better correlated with absolute geographical separation than proximity along rivers. These results are consistent with different dispersal mechanisms for snails and schistosomes and the implications for host-parasite coevolution are discussed.

Urinary schistosomiasis among schoolchildren in Ibadan, an urban community in south-western Nigeria

Abstract: Summary The current status of urinary schistosomiasis was assessed in Ibadan, an urban community in south-western Nigeria. Of 1331 children examined for eggs of S. haematobium in their urine, 17.4% were infected. Prevalence in postprimary schoolchildren was significantly (P 50 eggs/10 ml urine. 2.2% excreted S. mansoni eggs in urine. Water contact activities were more frequent (P < 0.01) in males (31.8%) than females (38.2%). Nine species of snails were encountered, with B. (p) globosus being the the most abundant and widespread. These results show that urinary schistosomiasis is still being actively being transmitted in Ibadan.

Impact of the crayfish Procambarus clarkii on Schistosoma haematobium transmission in Kenya.

Abstract: The Louisiana red swamp crayfish, Procambarus clarkii, which was introduced into east Africa in the 1950s or 1960s, has since widely dispersed. Previous work by our group has shown that P. clarkii can reduce populations of the molluscan intermediate hosts of human schistosomes through predatory and competitive interactions. Here, we investigate whether crayfish can reduce populations of Bulinus africanus and consequently, Schistosoma haematobium prevalence in school children. Children from 6 primary schools in the Machakos and Kitui Districts of Kenya were selected for study. Schools were divided into 3 experimental-control pairs. At experimental schools, crayfish were introduced into nearby aquatic habitats harboring Bulinus africanus snails and serving as S. haematobium transmission sites. Snail habitats near control schools did not receive crayfish. Six months after crayfish introduction, all infected children were treated with praziquantel. Children were then monitored quarterly for 2 years, at which time infection and reinfection rates were compared statistically between the paired schools. In one such pair, crayfish failed to establish, resulting in neither snail control nor a reduction in transmission. At the second pair of schools, the numbers of snails were decreased by the presence of crayfish, but a clear difference in infection rates in children could not be detected, primarily because drought conditions kept overall transmission rates low. At the third school pair, crayfish established well in experimental habitats, snail numbers decreased precipitously, and children at the experimental school were significantly less likely to acquire S. haematobium infections than children at the control school. Our results indicate that under certain environmental circumstances, P. clarkii exerts a significant impact on the transmission of human schistosomiasis in Kenya. Important questions remain regarding the impact of P. clarkii on Kenyan freshwater ecosystems, not the least of which is its potential to significantly influence the epidemiology of schistosomiasis in east Africa.

Resolution and resurgence of schistosoma haematobium-induced pathology after community-based chemotherapy in ghana, as detected by ultrasound.

Abstract: Community-based treatment is recommended for endemic populations with urinary schistosomiasis ; however, the optimal target group for treatment and retreatment interval have not been established. Using ultrasound, this study identified subpopulations whose lesions were most likely to respond to treatment and characterized resurgence of pathology. Ultrasound examination of 1202 infected patients was followed by chemotherapy with praziquantel. A sample of 698 patients was followed for 18 months after treatment. Nearly all types of bladder pathologies resolved after treatment, regardless of patient's age or intensity of initial infection. However, many patients' upper urinary tract pathologies (62.5%) did not resolve. During the 18-month follow-up period, reappearance of severe bladder pathologies was rare, and <10% of persons had resurgence of mild bladder pathologies. For this population, retreatment is not needed annually but might be cost effective if given several years later. Confirmation from other areas is required before general policies can be formed.

Acute Pulmonary Schistosomiasis in Travelers Returning from Lake Malawi, Sub-Saharan Africa

Abstract: We describe four cases of acute schistosomiasis presenting to the Infectious Diseases Unit of John Radcliffe Hospital (Oxford, England) during a 2-month period in autumn 1997. All four patients had swum in Lake Malawi, a freshwater lake in sub-Saharan Africa that is associated with Schistosoma haematobium and, less commonly, Schistosoma mansoni infections. All four patients had a severe acute illness and had prominent pulmonary involvement, both clinically and radiologically. This represents a change in the recognized pattern of presentation and could possibly reflect a new parasite variant in the lake.

The performance of school-based questionnaires of reported blood in urine in diagnosing Schistosoma haematobium infection: patterns by age and sex.

Abstract: This study investigates the performance of school-based questionnaires of reported blood in urine as an indicator of the prevalence of Schistosoma haematobium infection in schools and the presence of infection in individuals. In most schools (87%), the prevalence of reported blood in urine underestimates the prevalence of S. haematobium infection. Predictive value analysis suggests that a threshold of 30% reported blood in urine would identify most of the high prevalence schools (i.e. those with 50% or more children infected with S. haematobium). Although the prevalence of S. haematobium infection was greater in males than females, girls reported a lower prevalence of blood in urine than boys even at comparable levels of infection. Reported blood in urine in females was more specific (identifying 10% more uninfected girls than the sign in boys), but was far less sensitive (identifying less than 20% of infected girls than boys). The sensitivity of reported blood in urine was also related to age, being significantly lower in girls over 14 years of age. The proportion of infected children who reported blood in urine was also lower in schools where the prevalence of reported blood in urine is less than 30%. The results suggest that the selective treatment of children based on reported blood in urine in low prevalence schools would miss a high proportion of infected children, particularly girls. It remains unclear whether other rapid assessment techniques, such as the use of reagent strips, would offer greater cost-effectiveness.

Mating interactions between Schistosoma haematobium and S. mansoni.

Abstract: Schistosoma haematobium and S. mansoni are two medically important schistosomes, commonly occurring sympatrically in Africa and so potentially able to infect the same human host. Experiments were designed to study the mating behaviour of these two species in mixed infections in hamsters. Analysis of the data obtained showed that both heterospecific and homospecific pairs readily form. No significant difference was seen between the two species in their ability in forming pairs, however, S. mansoni showed a greater homospecific mate preference. Analysis of the data using the Mantel-Haenszel test suggests that mating competition does occur between S. haematobium and S. mansoni, the former being the more dominant species. Both species appeared to be able to change mate, with S. haematobium showing a greater ability in taking S. mansoni females away from S. mansoni males when introduced into a pre-established S. mansoni infection highlighting the competitiveness of S. haematobium. The significance of the results is discussed in relation to the epidemiological consequences occurring in Senegal, and other areas where both species are sympatric.

Biomonitoring of n-nitroso compounds, nitrite and nitrate in the urine of Egyptian bladder cancer patients with or without Schistosoma haematobium infection.

Abstract: The excretion of nitrate, nitrite, apparent total N-nitroso compounds and volatile nitrosamines was measured in 24 hr urine from 61 Egyptians, divided into 4 groups: controls, Schistosoma haematobium-infected patients and bladder cancer patients with and without a history of schistosomal infection. Urinary nitrate in S. haematobium-infected patients was significantly higher than in the other 3 groups. Nitrite was below the detection limit of the method (

Long-term suppression of adult bladder morbidity and severe hydronephrosis following selective population chemotherapy for Schistosoma haematobium.

Abstract: Repeated selective population chemotherapy of school age children reduces infection and morbidity associated with Schistosoma haematobium infection. To examine the long-term effect of this treatment on susceptibility to re-infection and late disease, a cohort of Kenyans (n = 194) were re-examined for infection and urinary tract morbidity 7-13 years after they underwent annual ultrasonography and treatment for an average of 5 years beginning in 1984 as children. Controls were previously untreated age-matched individuals residing in the same or adjacent villages. The overall prevalence and intensity of infection were equivalent between the 2 groups. In contrast, the prevalence of bladder wall pathology was 11-fold lower in previously treated (1.5%) versus untreated subjects (17%). Severe hydronephrosis was completely reversed. These data demonstrate that treatment significantly reduced urinary tract morbidity despite re-infection, and suggest that the important risk factors for urinary tract morbidity in adulthood are cumulative intensity and duration of infection during early adolescence.

The epidemiology of a recent focus of mixed Schistosoma haematobium and Schistosoma mansoni infections around the 'Lac de Guiers' in the Senegal River Basin, Senegal.

Abstract: A village with mixed Schistosoma mansoni and S. haematobium infections (probably in a early endemic phase) was identified around the Lac de Guiers in the Senegal River Basin. In documenting the epidemiology of both schistosomes, we focused on prevalence and intensity of infection, transmission patterns and the impact of treatment. S. mansoni prevalences (near 100%) and egg counts (overall geometric mean eggs per gram of faeces (epg) of 589 were high in all age groups, with 35% of individuals excreting > 1000 epg, and showing a slow decline in egg output only after the age of 30 years. The overall prevalence (28%) and egg counts (2% > 50 eggs/10 ml) of S. haematobium were low, with mean counts of 6.3 eggs/10 ml. Maximal mean S. mansoni egg counts were found in 5-9 year-old boys and in 15-19 year-old girls; S. haematobium maximal counts in 1-4 year-old boys and in girls aged 5-9. Extremely high Biomphalaria pfeifferi infection ratios were recorded over the whole year. Following a single treatment, re-infection was rapid with prevalences and mean egg counts of both Schistosoma species reaching pretreatment levels within 7 months.

Parameters associated with Schistosoma haematobium infection before and after chemotherapy in school children from two villages in the coast province of Kenya.

Abstract: We evaluated the impact of praziquantel therapy (40 mg/kg body weight) on indicators of infection with Schistosoma haematobium by following a cohort of infected children from schools located 12 km apart in the Coast province of Kenya, at 0, 2, 4, 6, 12 and 18 months after treatment. Within this period, measurements of infection parameters pertaining to egg counts and haematuria (micro-, macro- and history) were evaluated at all time points. The initial prevalence of 100% dropped significantly 8 weeks after treatment with a similar trend in the intensity of infection. Microhaematuria followed the same trend as observed for egg counts while macrohaematuria remained low after treatment. Reinfection following successful therapy differed significantly between schools; in one school the children were reinfected immediately while those in the other remained uninfected despite similar starting prevalences, intensities of infection and cure rates. Transmission between the two areas looked homogeneous before treatment but when both groups were treated, contrasting transmission patterns became evident. In a regression model we evaluated factors that might be associated with reinfection, and after allowing for pretreatment infection level, age and sex, area (school) remained a highly significant predictor.

Modification of behaviour and attitude in the control of schistosomiasis. 1. Observations on water-contact patterns and perception of infection.

Abstract: Observations on the water-contact patterns of 2136 residents of Adim community in Nigeria were conducted at four streams between February 1993 and January 1994. Urine samples collected from those observed were used to estimate the prevalence and intensity of Schistosoma haematobium infection. A questionnaire was also completed for each of the subjects, to test their perception of urinary schistosomiasis and its transmission. Infection was detected in 1076 (50.4%) of the subjects, with peak prevalence among those aged 10–14 years. Intensity of infection was more closely correlated with the number of water contacts (r = 0.97) than with the total duration of the exposure (r = 0.77), emphasising the importance of specific/multiple activities, and of the surface area of the body submerged, in transmission. One stream (Culvet) was identified as the main transmission point, with bathing/swimming and fishing as the main activities predisposing people to infection. The awareness of urinary schistosomiasis and its ...

School-based schistosomiasis control programmes: a comparative study on the prevalence and intensity of urinary schistosomiasis among Nigerian school-age children in and out of school.

Abstract: A cross-sectional study was conducted in February 1998 on the prevalence and intensity of urinary schistosomiasis among school-age children in and out of school at Adim village in Nigeria to test the objective of delivering a control programme through the school system. School enrollment figures and non-attendance rate were collated from questionnaires that were self-administered by heads of families. Prevalence and intensity of infection were determined following filtration of urine and counting of carbol fuchsin-stained eggs of Schistosoma haematobium. The rates of regular school attendance, irregular attendance and non-attendance were 69.1%, 5.1%, and 25.8%, respectively. These indices were not significantly associated with the age of the schoolchildren (P > 0.05). Boys (76.6%) were more associated with regular attendance than girls (61.4%) (P 0.05). The same association was established in the variation of mean egg count between the 2 study populations though intensity was higher among out-of-school children. The principal reasons proffered for the high rate of non-attendance listed in their order of importance were: economic, sickness, poor performance, refusal, farming and fishing. A dual method of control that would in incorporate the integration of recognized local authorities is suggested in areas with moderate school attendance rate like Adim, as lack of treatment of infected out-of-school children ensures continuous contamination and re-infection.

Urine circulating soluble egg antigen in relation to egg counts, hematuria, and urinary tract pathology before and after treatment in children infected with Schistosoma haematobium in Kenya.

Abstract: A cohort of 117 school children infected with Schistosoma haematobium was followed-up after therapy with praziquantel (0, 2, 4, 6, 12, and 18 months) and various infection and morbidity parameters (egg counts, hematuria, soluble egg antigen [SEA] in urine, and ultrasonography-detectable pathology) were quantified. At the onset of the study, 97% of the children were positive for S. haematobium with a geometric mean egg count of 45.7 eggs/10 ml of urine. Eighty-one percent of the children were positive for SEA in urine with a geometric mean SEA concentration of 218.8 ng/ml of urine. Ninety-two percent and 56% of the children were microhematuria positive and macrohematuria positive, respectively. Two months after treatment, all infection and morbidity indicators had significantly decreased. Reinfection after treatment as determined by detection of eggs in urine was observed by four months post-treatment while the other parameters remained low. The clearance of SEA was slower than that of egg counts while pathology resolved at an even slower pace. Levels of SEA and egg output showed similar correlations with ultrasound detectable pathology; these correlations were better than the correlation between hematuria and pathology.

Planning chemotherapy based schistosomiasis control: validation of a mathematical model using data on Schistosoma haematobium from Pemba, Tanzania.

Abstract: A mathematical model, based on a deterministic differential equation framework, has been developed to predict the impact of community chemotherapy programmes for human schistosomiasis. Here, this model is validated using data collected from a long-term control programme for urinary schistosomiasis on the island of Pemba, Zanzibar, United Republic of Tanzania, initiated in 1986 and still ongoing, in which schoolchildren were offered praziquantel chemotherapy every 6 months. Prevalence of infection and blood in urine were monitored in all the schools (total 26000 children from 60 schools) and more detailed data were collected in selected evaluation schools. Model predictions were run by using the initial prevalence as input. The predictions were very close to the observed decreases in prevalence and in prevalence of blood in urine. The correspondence improved further when the data were combined, going from single school level to district, and when the entire data set was combined. The accuracy of the predictions suggests that this model could be used as a tool to predict the consequences of chemotherapy control programmes. It is currently in press as a Windows software package under the name of 'EpiSchisto'.

Schistosomal granuloma modulation

Abstract: Recurrent experimental evidence indicates that schistosomal egg granuloma formation – at least in the murine model – results from a host response generated against both egg- and worm-derived antigens. Further experiments aimed at identifying the existence in vivo of cross-sensitization between Schistosoma haematobium worms and S. mansoni-derived egg antigens were performed with respect to S. mansoni egg antigen-induced granuloma formation and fibrogenesis in the liver. Male OF1 mice bisexually infected with S. haematobium or S. mansoni were hepatically challenged (cecal vein injection) with S. mansoni SEA (soluble egg antigen)-coupled Sepharose beads at the end of prepatent infection (8–10 days prior to the start of egg deposition). The mean granuloma volume (MGV) of in-vivo-generated synchronized hepatic granulomas (8 days old) and the fibrotic response were estimated. Just like S. mansoni-infected rodents, mice carrying an S. haematobium infection generated an accelerated hepatic granulomogenesis [respective MGVs 4.72 ± 0.56 and 5.41 ± 0.75 × 106 μm3; P < 0.0001 versus unsensitized (MGV 3.00 ± 0.40 × 106 μm3) mice] and an enhanced fibrotic response against S. mansoni SEA. They also had significantly enlarged spleens (P < 0.0001) and moderately enlarged livers (P = 0.02) as compared with S. haematobium-infected mice that were not challenged with SEA. From these observations we infer that in vivo, S. haematobium worms can positively modulate S. mansoni egg antigen-induced granuloma formation and hepatic fibrogenesis, resulting in more severe liver pathology.

The effect of different treatment regimens on the epidemiology of seasonally transmitted Schistosoma haematobium infections in four villages in the Senegal River Basin, Senegal.

Abstract: This paper describes the present epidemiological situation of Schistosoma haematobium in 4 villages in the middle valley of the Senegal River Basin, in terms of level and intensity of infection, seasonality of transmission, and intermediate hosts, and the effect of different treatment schedules with praziquantel on the overall infection levels and re-infection rates. The longitudinal study involving 7 surveys was carried out between June 1995 and March 1997 in Diatar, Guia, Donaye and Niandane. The prevalence and intensity of infection remained low throughout the survey ( 24 years produced >50 eggs/10 mL urine. Using WHO guidelines mass treatment was given to all Diatar and Guia villagers in December 1995, whereas in Donaye and Niandane only individuals positive for eggs were treated. Six weeks post-treatment cure rates in all villages were >80%, with marked declines in levels of infection ( 20%), due to the alternation of individuals apparently positive and negative between surveys. Water and infected snails were present from June to March. Therefore, owing to the high aggregation of infections in children, the low overall infection levels and the transmission period, it is suggested that in this area the best treatment schedule would be selective treatment of school-aged children in March/April, probably on an annual basis.

Schistosomiasis in the region of Ziga (Burkina Faso) before the construction of a dam

Abstract: The authors report the results of a survey on schistosomiasis in the zone of Ziga (Burkina Faso) where a dam is going to be built. They examined 438 children aged from 7 to 15 years in 5 villages. The appraisal of macroscopic or microscopic hematuria, urine filtration, stool analysis and ultrasonographic examination made possible the assessment of the prevalence and severity of both schistosomiasis. The area was hyperendemic for urinary schistosomiasis. The general prevalence of S. haematobium was higher than 46% and 55% of the children presented at least one lesion of the bladder and 2% of hydronephrosis at ultrasonography. Intestinal schistosomiasis was not observed although few cases have been described in the regional hospital and intermediate host snails have been collected in the area. A surveillance of schistosomiasis, based on school surveys, was strongly recommended in the dam area.

Diagnostic value of a miracidium in urinary sediment.

Abstract: Although rarely encountered in the United States, urinary tract schistosomiasis occurs commonly in many countries in the eastern hemisphere. Travel and immigration may contribute to imported cases of schistosomiasis, Excessive morbidity and increased mortality, including the development of urinary-tract squamous-cell carcinoma, are associated with untreated Schistosoma haematobium infection. Therefore, in the appropriate clinical context, all efforts should be made to rule out infectious and readily treatable causes of chronic hematuria. The presence of characteristic eggs in the urinary sediment is the usual means of diagnosing a S. haematobium infection. Additionally, the small and less commonly encountered miracidium stage of S. haematobium may also be present in the urine, which is another means of diagnosing urinary tract schistosomiasis. The present report describes a case in which a miracidium was detected in a fresh, unstained urine specimen. As detection of miracidia can be made in specimens also processed by routine cytologic methods, it behooves cytologists to be aware of this entity for the diagnosis of schistosomiasis.

Schistosoma haematobium: comparative studies on the characteristics of infection in three populations of Planorbarius metidjensis from the Agadir province in South Morocco.

Abstract: Planorbarius metidjensis measuring 2 or 3 mm in diameter and originating from three populations in the Agadir province (Ida Ou Gnidif, Imouzzer, and Sidi Belkacem) were experimentally infected with Schistosoma haematobium to determine if the complete larval development of the parasite might be ensured by any snail population of the Agadir province and to compare the general characteristics of infection. No significant difference between the three populations was noted in the survival rates of snails when the first shedding occurred or in the prevalence of infection. The mean duration of the shedding period was significantly higher in the Imouzzer population (111 days versus 53–58 days). The total number of cercariae shed per mollusc was significantly lower in the Ida Ou Gnidif planorbids (1,398/snail versus 3,346 and 3,343/snail in the other 2 groups). The same rhythm in daily cercarial production was noted in the three snail groups, with the periodicity being 18–20 days. Despite some differences in parasite development between the three snail populations, the different populations of P. metidjensis can ensure the complete development of S. haematobium and maintain local transmission in the South of Morocco.

[The prevalence of schistosomiasis in Togo. A cross-sectional study conducted in a school setting].

Abstract: As a prelude to a national campaign to control schistosomiasis in Togo, mass screening of school children in 22 prefectures was undertaken to determine the extent of endemic schistosomiasis. Children were randomly selected for testing. In each case, stool examinations using by the Kato-Katz method and urine tests (centrifugation of 10 ml) were performed to detect Schistosome eggs. A total of 2511 children were tested. The sex ratio was 1.7 and mean age 10.4 years (range: 5 to 20 years). The incidence of schistosomiasis was 26.7 p. 100. Schistosoma haematobium was the most widespread and active Schistosome species, being endemic in all locations studied. The incidence of Schistosoma haematobium ranged from 0.6 to 72 p. 100 (national mean: 25.5 p. 100). Schistosoma mansoni was prevalent in only 12 prefectures (range 0.6 to 10 p. 100; national average 2.2 p. 100). The rate of infection was highest in the age group between 10 and 20 years and the risk appeared to be significantly higher in males than in females (p < 0.05). This study confirmed the high incidence of schistosomiasis infection in Togo and identified hyperendemic areas in which control measures should be programmed first.

Laparoscopic evidence of upper genital schistosomiasis.

Abstract: This prospective study aimed at estimating the proportion of upper genital schistosomiasis in patients submitted to videoassisted laparoscopy and to describe carefully the bilharzial lesions seen at laparoscopy. Four hundred and thirty-four patients submitted to videolaparoscopy were included in this study. The pelvis was carefully explored for evidence of recent or old upper genital tract chronic inflammation. Suspicious areas like nodules, masses, vascular lesions, adhesions, pathologic tubes or ovarian cysts were biopsied. Positive cases of schistosomiasis were submitted to a thorough immunological evaluation. Diagnostic laparoscopy was carried out in 185 cases while the remaining patients required operative intervention. Biopsy was taken from 128 cases (29.8%) which revealed schistosomiasis in four cases only (0.9%) who demonstrated high titre of antibodies against Schistosoma haematobium. Despite being a rare disease, upper genital schistosomiasis should be considered as a possible cause in all cases...

Interleukin-4, immunoglobulin E and immunoglobulin A and resistance to re-infection with Schistosoma haematobium before and after chemotherapy.

Abstract: The role of serum IL-4, IgE and IgA in protective immunity had been determined in 88- S. haematobium infected-individuals before and 3, 6, 9 and 12 months after treatment with a single dose of praziquantel. Before treatment, IL-4 level was found to be highly significant in all stages of infection, there was a positive correlation between IL-4 levels and egg count. Whereas serum IgE and IgA levels were significantly high in late infected group showing a negative correlation with egg count. After praziquantel treatment, IL-4 levels decreased gradually while IgE and IgA levels were significantly increased in all patients. At 9 and 12 months, viable ova were detected in 11 cases (12.5%), they were re-infected after treatment showing an increase in IL-4 levels, and a decrease in both serum IgE and IgA. These results indicate that IL-4 plays an important role in suppression of severe inflammatory responses associate with persistence of the parasitic stages. Also, serum IgE and IgA participate in protective immunity against S. haematobium infection. It may be essential to administer a second dose of praziquantel to all persons living in endemic areas who are likely to be in contact with infested water.