Application of Schistosomiasis Consortium for Operational Research and Evaluation Study Findings to Refine Predictive Modeling of Schistosoma mansoni and Schistosoma haematobium Control in Sub-Saharan Africa.

An essential mission of the Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was to help inform global health practices related to the control and elimination of schistosomiasis. To provide more accurate, evidence-based projections of the most likely impact of different control interventions, whether implemented alone or in combination, SCORE supported mathematical modeling teams to provide simulations of community-level Schistosoma infection outcomes in the setting of real or hypothetical programs implementing multiyear mass drug administration (MDA) for parasite control. These models were calibrated using SCORE experience with Schistosoma mansoni and Schistosoma haematobium gaining and sustaining control studies, and with data from comparable programs that used community-based or school-based praziquantel MDA in other parts of sub-Saharan Africa. From 2010 to 2019, models were developed and refined, first to project the likely SCORE control outcomes, and later to more accurately reflect impact of MDA across different transmission settings, including the role of snail ecology and the impact of seasonal rainfall on snail abundance. Starting in 2014, SCORE modeling projections were also compared with the models of colleagues in the Neglected Tropical Diseases Modelling Consortium. To explore further possible improvement to program-based control, later simulations examined the cost-effectiveness of combining MDA with environmental snail control, and the utility of early impact assessment to more quickly identify persistent hot spots of transmission. This article provides a nontechnical summary of the 11 SCORE-related modeling projects and provides links to the original open-access articles describing model development and projections relevant to schistosomiasis control policy.

Molecular diversity of Bulinus species in Madziwa area, Shamva district in Zimbabwe: implications for urogenital schistosomiasis transmission.

BACKGROUND: Bulinus species are freshwater snails that transmit the parasitic trematode Schistosoma haematobium. Despite their importance, the diversity of these intermediate host snails and their evolutionary history is still unclear in Zimbabwe. Bulinus globosus and B. truncatus collected from a urogenital schistosomiasis endemic region in the Madziwa area of Zimbabwe were characterized using molecular methods. METHODS: Malacological survey sites were mapped and snails were collected from water contact sites in four communities in the Madziwa area, Shamva district for a period of one year, at three-month intervals. Schistosoma haematobium infections in snails were determined by cercarial shedding and the partial mitochondrial cytochrome c oxidase subunit 1 gene (cox1) was used to investigate the phylogeny and genetic variability of the Bulinus spp. collected. RESULTS: Among the 1570 Bulinus spp. snails collected, 30 (1.9%) B. globosus were shedding morphologically identified schistosomes. None of the B. truncatus snails were shedding. The mitochondrial cox1 data from 166 and 16 samples for B. globosus and B. truncatus, respectively, showed genetically diverse populations within the two species. Twelve cox1 haplotypes were found from the 166 B. globosus samples and three from the 16 B. truncatus samples with phylogenetic analysis showing that the haplotypes fall into well-supported clusters within their species groups. Both B. truncatus and B. globosus clustered into two distinct lineages. Overall, significant negative values for both Tajima's D statistic and the Fu's Fs statistic were observed for B. globosus and B. truncatus. CONCLUSIONS: The study provided new insights into the levels of genetic diversity within B. globosus and additional information on B. truncatus collected from a small geographical area in Zimbabwe. Low prevalence levels of infection observed in the snails may reflect the low transmission level of urogenital schistosomiasis in the area. Our results contribute towards the understanding of the distribution and population genetic structure of Bulinus spp. supporting the mapping of the transmission or risk of transmission of urogenital schistosomiasis, particularly in Zimbabwe.

Introgression in Lake Malawi: increasing the threat of human urogenital schistosomiasis?

For the last 15 years, we have studied the relationships among cichlid snail-eating fishes, intermediate snail-host density, and the prevalence of human infection of Schistosoma haematobium in Lake Malawi and concluded that the increase of human infection is correlated with the decrease in snail-eating fishes in the shallow waters of the lake. We postulated that a strain of S. haematobium from other parts of Africa, which was introduced into the Cape Maclear region of Lake Malawi by tourists, was compatible with Bulinus nyassanus-which is a close relative of B. truncatus, and interbred with the indigenous strain of S. haematobium, which ultimately produced via introgression a strain that can use both B. globosus and B. nyassanus as intermediate hosts. This actively evolving situation involving intermediate snail-host switching and decline of Trematocranus placodon, a natural cichlid snail predator, will impact on transmission of urogenital schistosomiasis within the local communities and on tourists who visit Lake Malawi.

Antigen-specific B memory cell responses to Plasmodium falciparum malaria antigens and Schistosoma haematobium antigens in co-infected Malian children.

Polyparasitism is common in the developing world. We have previously demonstrated that schistosomiasis-positive (SP) Malian children have age-dependent protection from malaria compared to matched schistosomiasis-negative (SN) children. Evidence of durable immunologic memory to malaria antigens is conflicting, particularly in young children and the effect of concomitant schistomiasis upon acquisition of memory is unknown. We examined antigen-specific B memory cell (MBC) frequencies (expressed as percentage of total number of IgG-secreting cells) in 84 Malian children aged 4-14 to malaria blood-stage antigens, apical membrane antigen 1 (AMA-1) and merozoite surface protein 1 (MSP-1) and to schistosomal antigens, Soluble Worm Antigenic Preparation (SWAP) and Schistosoma Egg Antigen (SEA), at a time point during the malaria transmission season and a follow-up dry season visit. We demonstrate, for the first time, MBC responses to S. haematobium antigens in Malian children with urinary egg excretion and provide evidence of seasonal acquisition of immunologic memory, age-associated differences in MBC acquisition, and correlation with circulating S. haematobium antibody. Moreover, the presence of a parasitic co-infection resulted in older children, aged 9-14 years, with underlying S. haematobium infection having significantly more MBC response to malaria antigens (AMA1 and MSP1) than their age-matched SN counterparts. We conclude that detectable MBC response can be measured against both malaria and schistosomal antigens and that the presence of S. haematobium may be associated with enhanced MBC induction in an age-specific manner.

Schistosomiasis haematobium prevalence and risk factors in a school-age population of peri-urban Lusaka, Zambia.

Given association of the parasite Schistosoma haematobium with coastal and rural/agricultural populations, there is little documentation to date of infection patterns in today's rapidly urbanizing non-coastal regions. We conducted an observational study of 5-17-year-old school children (N = 1583) in peri-urban compounds of Lusaka, Zambia. Demographic information, medical history, physical examination findings and urinalysis results were recorded. Prevalence of schistosomiasis in the population was 20.72%. Significant risk factors for infection were male gender [odds ratio (OR) 2.42], age of 9-12 years or 13-17 years (OR 3.33 and 3.26, respectively, compared with 5-8-year-olds) and single and/or double orphan status (OR 1.43). Clinical officers detected schistosomiasis with a sensitivity of 24.70% and a specificity of 98.17% after history and physical examination. These results reveal that peri-urban populations have a significant but under-recognized vulnerability to infection, and suggest that only history and physical examination are inadequate for identifying a treatment population.

The epidemiology and small-scale spatial heterogeneity of urinary schistosomiasis in Lusaka province, Zambia.

In line with the aims of the "National Bilharzia Control Programme" and the "School Health and Nutrition Programme" in Zambia, a study on urinary schistosomiasis was conducted in 20 primary schools of Lusaka province to further our understanding of the epidemiology of the infection, and to enhance spatial targeting of control. We investigated risk factors associated with urinary schistosomiasis, and examined small-scale spatial heterogeneity in prevalence, using data collected from 1,912 schoolchildren, 6 to 15-year-old, recruited from 20 schools in Kafue and Luangwa districts. The risk factors identified included geographical location, altitude, normalized difference vegetation index (NDVI), maximum temperature, age, sex of the child and intermediate host snail abundance. Three logistic regression models were fitted assuming different random effects to allow for spatial structuring. The mean prevalence rate was 9.6%, with significance difference between young and older children (odds ratio (OR) = 0.71; 95% confidence interval (CI) = 0.51-0.96). The risk of infection was related to intermediate host snail abundance (OR = 1.03; 95% CI = 1.00-1.05) and vegetation cover (OR = 1.04; 95% CI = 1.00-1.07). Schools located either on the plateau and the valley also differed in prevalence and intensity of infection for moderate infection to none (OR = 1.64; 95% CI = 1.36- 1.96). The overall predictive performance of the spatial random effects model was higher than the ordinary logistic regression. In addition, evidence of heterogeneity of the infection risk was found at the micro-geographical level. A sound understanding of small-scale heterogeneity, caused by spatial aggregation of schoolchildren, is important to inform health planners for implementing control schistosomiasis interventions.

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.

Urinary schistosomiasis: an uncommon cause of gross hematuria in the industrialized countries.

Schistosomiasis is a parasitic disease that can cause significant illness in humans. While schistosomiasis is not found in the United States and other developed countries, 200 million people are infected worldwide. It is estimated that 400,000 infected persons immigrate to the United States and present to emergency departments with either acute or chronic schistosomiasis. Schistosomiasis can be expected to be seen with increasing frequency in the United States and other developed countries with the continuing influx of immigrants, as well as the return of travelers and soldiers from endemic areas. Although there are several etiologies of gross hematuria in children, schistosomiasis is an uncommon cause of gross hematuria in the industrialized world. The purpose of this report is to bring awareness to health-care providers in the United States and other developed countries of this uncommon cause of gross hematuria, as prompt diagnosis and treatment can result in quick resolution of symptoms.

[Neuroschistosomiasis: a challenging diagnosis]. / Neuroesquistosomiasis: un reto para el diagnóstico.

INTRODUCTION: Neuroschistosomiasis is an uncommon and under diagnosed disease in our country because of the no clinical suspicion. The most common neurological manifestations are epileptic seizures as central nervous system involvement or different types of myelopathies: transverse myelitis, myeloradiculopathy, cauda equina syndrome or Brown-Sequard syndrome. CASE REPORT: A 27 years-old male from an endemic area, with atypical neurological affectation as he presented myelopathy and multifocal neuritis. Diagnosis was based on the epidemiological exposure datums, the myelopathy, the positive serological studies for Schistosoma haematobium, no detection of other parasitic infections and the clinical and radiological improvement after treatment. Cervical and thoracic magnetic resonance showed areas of hyper signal in T2 as it was described in other cases. It was detected S. haematobium in the bladder, the rest of serological and microbiological studies were negative. Besides, eosinophils on the biopsy of sural nerve orientative to parasitic etiology. CONCLUSION: In patient with myelopathy or another unexplained neurological manifestation we have to suspect neuroschistosomiasis. In a world where migrations and travels are so frequent we have to think in this type of diseases.

Neuroesquistosomiasis: un reto para el diagnóstico / Neurochistosomiasis: a challenging diagnosis

Introducción. La neuroesquistosomiasis es una entidad poco frecuente e infradiagnosticada en nuestro medio por la falta de sospecha clínica. Las formas más habituales de presentación son afectación cerebral o distintas variantes de mielopatías: mielitis transversa, mielorradiculopatía, síndrome de cola de caballo, síndrome de Brown-Séquard. Caso clínico. Varón de 27 años oriundo de zona endémica, con afectación neurológica atípica, pues presenta sintomatología medular y neuropatía multifocal. Los datos epidemiológicos de exposición, la clínica de mielopatía, la serología positiva para Schistosoma haematobium, el descarte de otras posibles parasitosis y la mejoría tanto clínica como radiológica tras el tratamiento nos han permitido llegar al diagnóstico. Las imágenes cervicales y dorsales observadas en la resonancia magnética son similares a las descritas en otras ocasiones. En la investigación etiológica se detecta S. haematobium vesical, siendo el resto de serologías y análisis microbiológicos negativos. Además la presencia de eosinófilos en la biopsia del nervio sural orienta hacia el origen parasitario de dicha afectación. Conclusión. Ante un paciente con mielopatía u otra afectación neurológica no explicada debemos sospechar neuroesquistomiasis. En un mundo donde las migraciones y los viajes son tan frecuentes, cada día debemos pensar más en este tipo de enfermedades de origen tropical

Introduction. Neuroschistosomiasis is an uncommon and under diagnosed disease in our country because of the no clinical suspicion. The most common neurological manifestations are epileptic seizures as central nervous system involvement or different types of myelopathies: transverse myelitis, myeloradiculopathy, cauda equina syndrome or Brown-Séquard syndrome. Case report. A 27 years-old male from an endemic area, with atypical neurological affectation as he presented myelopathy and multifocal neuritis. Diagnosis was based on the epidemiological exposure datums, the myelopathy, the positive serological studies for Schistosoma haematobium, no detection of other parasitic infections and the clinical and radiological improvement after treatment. Cervical and thoracic magnetic resonance showed areas of hyper signal in T2 as it was described in other cases. It was detected S. haematobium in the bladder, the rest of serological and microbiological studies were negative. Besides, eosinophils on the biopsy of sural nerve orientative to parasitic etiology. Conclusion. In patient with myelopathy or another unexplained neurological manifestation we have to suspect neuroschistosomiasis. In a world where migrations and travels are so frequents we have to think in this type of diseases

Esquistosomiasis vesical, aportación de un caso y revisión de la literatura española / Vesical schistosomiasis, case report and spanish literature review

La esquistosomiasis urinaria es una parasitosis provocada por Schistosoma haematobium. Es una enfermedad endémica que afecta a casi toda África y Oriente Medio. Presentamos un caso de un varón joven emigrante de Mali que consultó por hematuria terminal y síndrome miccional irritativo ocasional de un año de evolución. El estudio parasitológico en orina detectó huevos de Schistosoma y la ecografía objetivó una posible neoformación vesical. Tras RTU, el análisis anatomopatológico confirmó la presencia de esquistosomiasis vesical. Actualmente, el paciente está asintomático tras tratamiento con Praziquantel

Urinary schistosomiasis is an infection caused by parasite, Schistosoma haematobium. Squistosomiasis is an endemic disease in Africa and Middle East. We are presenting a case of a young immigrant male from Mali that came to our clinic with hematuria and miccional irritative syndrome during a year. Parasitological study reported Schimosoma´s eggs and ecography showed a possible vesical newformation. After RTU, anatomopatological study confirms the presence of a vesical esquistosomiasis. Now pacient is asyntomatic after he was treated with Praziquantel

Parasitismo exótico en becarios extranjeros / Exotic parasitism in foreign fellow holders

Se realiza una exposición de los casos notificados como parasitismo exótico en becarios extranjeros, radicados en la provincia de Villa Clara, en el período comprendido entre 1992 y 1997. Los casos positivos son varones en su mayoría; los parásitos más frecuentes fueron el Schistosoma haematobium, el Schistosoma mansoni y la Filaria loa-loa. Se mantiene el pesquisaje de estas afecciones y otras que pudieran presentarse para evitar su propagación en el país (AU)

The WHO Collaborating Centre for Research and Control of Schistosomiasis at Niamey, Niger.

The Centre de Recherche sur les Méningites et les Schistosomes (CERMES) is a research institute depending on the Organisation de Coordination et de Coopération pour la lutte contre les Grandes Endémies--a West African Organization for Public Health--devoted to the studies on schistosomiasis and meningitis. The staff includes 32 persons with 11 scientists and one financial officer. The activities of the CERMES involving schistosomiasis concern three research units: (a) ecology of human and animal schistosomiasis transmission; the CERMES defined the different patterns of schistosomiasis transmission in Niger (involving African dry savana); in this field, we have shown, (i) the existence of important variability in conditions of transmission of S. haematobium and, (ii) natural hybridization between parasitic species of the ruminants (S. bovis and S. curassoni) and genetic interaction between human and animal parasites; (b) definition of morbidity indicators usable for rapid assessment methods, for appraisal of the severity of the disease and for the evaluation of the efficiency of control methods; we have established the correlation between ultrasonographic data and some cheap and simple field indicators; (c) immune response and protective immunity induced by recombinant glutathion S-transferase (Sm28, Sb28 and Sh28) in homologous and heterologous animal models including goats, sheep and non human primates (Erythrocebus patas). In Niger, we participate in all control programs against schistosomiasis to define control strategies, to supervise operations and to participate in their evaluation with external experts. International collaborations constitute a frame including four laboratories in Africa and six laboratories in developed countries (Europe and USA).

PIP: The Centre de Recherche sur les Meningites et les Schistosomoses (CERMES), a research center in Niamey, Niger, affiliated with a West African public health organization, conducts studies in the areas of parasitology, epidemiology, and immunology. Significant variability in factors related to transmission of Schistosoma haematobium have been noted. Experimental research on the Schistosoma-bulinid compatibility and field surveys of the geographic distribution and role of snails in transmission have been essential to the design of parasite control interventions in West Africa. A CERMES-sponsored project, supported by the European Community, is examining urinary schistosomiasis control in the Niger river valley and the impact of treatment on ultrasonically visualized urologic lesions. The Experimental Vaccine Unit seeks to improve the route of administration and choice of adjuvant and to propose a vaccine protocol for field testing. Recombinant proteins have been found to alter the development of the parasite either by inducing a reduction in the parasite burden or an inhibition of the fecundity of the parasite.

Susceptibility of Ethiopian bulinid snails to Schistosoma haematobium from Somalia.

Susceptibility of four Ethiopian bulinid snails to a Somalian strain of S. haematobium was tested. Bulinus abyssinicus was highly susceptible and lowland B. africanus was partially susceptible while B. truncatus and B. forskalii were refractory to the parasite. It is suggested that Ethiopian refugees returning from Somalia and/or Somalian refugees entering Ethiopia should be screened and treated for S. haematobium before they are allowed to work/resettle in development areas where B. abyssinicus and B. africanus are known or ecologically suspected to occur.

Prevalence of schistosoma haematobium for 35 villages in six chiefdoms in the Kanema District; Eastern Province of Sierra Leone

The study of the prevalence of schistosoma haematobium was conducted in July; 1990 in the Kenama District; Eastern Province of Sierra Leone. The crude prevalence was 32.6 per cent. The over-all prevalence was signicantly higher in females than in males but the age-specific prevalence was significantly higher in the 1-10 years cohort of males that female counterparts

Lung-stage expression of a major schistosome surface antigen.

The topographical expression of a glycoprotein of 180,000 molecular weight on the surface of lung-stage Schistosoma mansoni schistosomula was determined by immunofluorescence microscopy using a monoclonal antibody. Postfixation treatment with graded ethanols enhanced specific immunofluorescent staining of adult worms, and was required for detection of the antigen on the surfaces of lung-stage schistosomula. The epitope recognized by the monoclonal antibody was also present on the surfaces of adult Schistosoma haematobium, but not on those of Schistosoma japonicum.