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Trends in Parasitology Feb 2021is the causative agent of intestinal schistosomiasis and infects ~54 million people annually, causing significant mortality and morbidity. This parasitic trematode is...
is the causative agent of intestinal schistosomiasis and infects ~54 million people annually, causing significant mortality and morbidity. This parasitic trematode is endemic in sub-Saharan Africa and the Middle East, and colonized South America during the transatlantic slave trade. Parasites transition between five distinctive body plans, with asexual proliferation in the snail host and sexual proliferation in the vertebrate host, and motile free-living stages. Transmission results from contact with water containing infected . snails. Infection prevalence and intensity peaks in school age children: both reduced water contact and acquired immunity reduces infection in adults. Pathology to the human host results from granulomas that form around eggs trapped in the liver and gut. These is no effective vaccine available: treatment of infected patients with praziquantel is the mainstay of control efforts.
Topics: Animals; Anthelmintics; Humans; Life Cycle Stages; Schistosoma mansoni; Schistosomiasis mansoni; Snails
PubMed: 32713763
DOI: 10.1016/j.pt.2020.06.003 -
Revista de Saude Publica Apr 2013To perform a systematic review of the prevalence of the HCV/ S. mansoni co-infection and associated factors in Schistosoma mansoni -infected populations. (Review)
Review
OBJECTIVE
To perform a systematic review of the prevalence of the HCV/ S. mansoni co-infection and associated factors in Schistosoma mansoni -infected populations.
METHODS
The bibliographic search was carried out using the Medline, Lilacs, SciELO, Cochrane Library and Ibecs databases. The criteria for the studies' selection and the extraction data were based on systematic review methods. Forty five studies were found, with nine being excluded in a first screening. Thirteen articles were used for data extraction.
RESULTS
The HCV infection rates in schistosomiasis populations range from 1% in Ethiopia to 50% in Egypt. Several studies had poorly defined methodologies, even in areas characterized by an association between hepatitis C and schistosomiasis, such as Brazil and Egypt, which meant conclusions were inconsistent. HCV infection rates in schistosomotic populations were heterogeneous and risk factors for acquiring the virus varied widely.
CONCLUSIONS
Despite the limitations, this review may help to identify regions with higher rates of hepatitis C and schistosomiasis association. However, more studies are necessary for the development of public health policies on prevention and control of both diseases.
Topics: Brazil; Coinfection; Endemic Diseases; Hepatitis C; Humans; Prevalence; Risk Factors; Schistosomiasis mansoni
PubMed: 24037369
DOI: 10.1590/S0034-910.2013047004247 -
The American Journal of Tropical... Jul 2020The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was established in late 2008 to conduct operational research that would inform practices... (Review)
Review
The Schistosomiasis Consortium for Operational Research and Evaluation (SCORE) was established in late 2008 to conduct operational research that would inform practices related to the control and elimination of schistosomiasis. This article traces SCORE's beginnings and underpinnings. These include an emphasis on openness and contributing to the development of a cohesive schistosomiasis control community, building linkages between researchers and national programs, and focusing on answering questions that will help Neglected Tropical Disease program managers to better control and eliminate schistosomiasis. It describes the development and implementation of SCORE's multiple projects. SCORE began by drawing on advice from a broad range of experts by holding wide-ranging meetings that informed the priorities and protocols for SCORE research. SCORE's major efforts included large, multicountry field studies comparing multiple strategies for mass drug administration with praziquantel, assessment of approaches to elimination, evaluation of a point-of-care assay for field mapping , and increasing the sensitivity of a laboratory-based diagnostic. SCORE also supported studies on morbidity due to schistosomiasis, quantification of vector snails and the detection of schistosome infections in snails, and changes in schistosome population genetics under praziquantel drug pressure. SCORE data and specimens are archived and will remain available for future research. Although much remains to be carried out, our hope is that through the already published articles and SCORE results described in this supplement, we will have provided a body of evidence to assist policy makers in the development of judicious guidelines for the control and elimination of schistosomiasis.
Topics: Animals; Disease Reservoirs; Disease Vectors; History, 21st Century; Humans; Mass Drug Administration; Morbidity; Neglected Diseases; Parasitology; Praziquantel; Prevalence; Schistosoma haematobium; Schistosoma mansoni; Schistosomiasis; Schistosomiasis mansoni; Snails
PubMed: 32400343
DOI: 10.4269/ajtmh.19-0785 -
Memorias Do Instituto Oswaldo Cruz Jul 2010Acute schistosomiasis is a systemic hypersensitivity reaction against the migrating schistosomula and eggs. A variety of clinical manifestations appear during the... (Review)
Review
Acute schistosomiasis is a systemic hypersensitivity reaction against the migrating schistosomula and eggs. A variety of clinical manifestations appear during the migration of schistosomes in humans: cercarial dermatitis, fever, pneumonia, diarrhoea, hepatomegaly, splenomegaly, skin lesions, liver abscesses, brain tumours and myeloradiculopathy. Hypereosinophilia is common and aids diagnosis. The disease has been overlooked, misdiagnosed, underestimated and underreported in endemic areas, but risk groups are well known, including military recruits, some religious congregations, rural tourists and people practicing recreational water sports. Serology may help in diagnosis, but the finding of necrotic-exudative granulomata in a liver biopsy specimen is pathognomonic. Differentials include malaria, tuberculosis, typhoid fever, kala-azar, prolonged Salmonella bacteraemia, lymphoma, toxocariasis, liver abscesses and fever of undetermined origin. For symptomatic hospitalised patients, treatment with steroids and schistosomicides is recommended. Treatment is curative in those timely diagnosed.
Topics: Acute Disease; Animals; Female; Humans; Male; Schistosomiasis mansoni; Schistosomicides
PubMed: 20721485
DOI: 10.1590/s0074-02762010000400012 -
Tuberkuloz Ve Toraks Sep 2017Schistosomiasis is one of the most prevelant parazitic diseases in the world. It is endemic in more than 70 countries, and more than 200 million people worldwide are... (Review)
Review
Schistosomiasis is one of the most prevelant parazitic diseases in the world. It is endemic in more than 70 countries, and more than 200 million people worldwide are infected with Schistosoma. Pulmonary hypertension (PHT) is one of the chronic complications of schistosomiasis. The exact pathogenesis of schistosomiasis-associated pulmonary hypertension (S-PHT) remains unclear, although several mechanisms such as parazitic arterial embolisation, pulmonary arteriopathy, and portopulmonary hypertension have been suggested. Pathological pulmonary vascular changes in S-PHT were found similar to those in idiopathic pulmonary arterial hypertension (IPAH). The fact that schistosomiasis is one of the most common causes of pulmonary arterial hypertension (PAH), particularly in the developing countries, underlines the importance of enhancing our knowledge on this disease. Developments in the treatment of PAH have resulted in improved prognosis and significant increase in life expectancy and quality of life in the last two decades, which has enhanced the importance of S-PHT. Schistosomiasis is treated with praziquantel. Nevertheless, there is limited evidence that this treatment is effective for PHT. Although antihelmintic medications do not lead to significant improvement, they have beneficial effects and may slow down disease progression. Using PAH-specific treatments in the patients with schistosomiasis-associated PAH (S-PAH) can improve prognosis. However, inadequate clinical studies and limited sources in the endemic regions restrict extensive usage of these expensive medications. Further studies are required to determine the efficacy of these treatment modalities.
Topics: Animals; Developing Countries; Familial Primary Pulmonary Hypertension; Humans; Hypertension, Pulmonary; Lung; Prognosis; Schistosoma mansoni; Schistosomiasis mansoni
PubMed: 29135402
DOI: 10.5578/tt.53798 -
Parasitology Research Jul 2022MicroRNAs (miRNAs) play regulatory roles in several diseases. In schistosomiasis, the main pathological changes are caused by the granulomatous reaction induced by egg...
MicroRNAs (miRNAs) play regulatory roles in several diseases. In schistosomiasis, the main pathological changes are caused by the granulomatous reaction induced by egg deposition. We aimed to study the changes in host miRNA-223 and miRNA-146b expression in relation to egg deposition and development of hepatic pathology in murine schistosomiasis mansoni. Blood and liver tissue samples were collected from non-infected mice (group I), S. mansoni-infected mice at the 4th, 8th, and 12th weeks post-infection (p.i.) (groups II-IV), and 4 weeks after praziquantel treatment (group V). The collected samples were processed for RNA extraction, reverse transcription, and real-time PCR analysis of miRNA-223 and miRNA-146b. miRNAs' relative expression was estimated by the ΔΔC method. Liver tissue samples were examined for egg count estimation and histopathological evaluation. Results revealed that miRNA-223 was significantly downregulated in liver tissues 8 and 12 weeks p.i., whereas miRNA-146b expression increased gradually with the progression of infection with a significantly higher level at week 12 p.i. compared to week 4 p.i. Serum expression levels nearly followed the same pattern as the tissue levels. The dysregulated expression of miRNAs correlated with liver egg counts and was more obvious with the demonstration of chronic granulomas, fibrous transformation, and distorted hepatic architecture 12 weeks p.i. Restoration of normal expression levels was observed 4 weeks after treatment. Collectively, these findings provide new insights for in-depth understanding of host-parasite interaction in schistosomiasis and pave a new way for monitoring the progress of hepatic pathology before and after treatment.
Topics: Animals; Liver; Mice; MicroRNAs; Schistosoma mansoni; Schistosomiasis; Schistosomiasis mansoni
PubMed: 35576078
DOI: 10.1007/s00436-022-07542-3 -
Clinical Infectious Diseases : An... May 2022Despite decades of interventions, 240 million people have schistosomiasis. Infections cannot be directly observed, and egg-based Kato-Katz thick smears lack sensitivity,...
BACKGROUND
Despite decades of interventions, 240 million people have schistosomiasis. Infections cannot be directly observed, and egg-based Kato-Katz thick smears lack sensitivity, affected treatment efficacy and reinfection rate estimates. The point-of-care circulating cathodic antigen (referred to from here as POC-CCA+) test is advocated as an improvement on the Kato-Katz method, but improved estimates are limited by ambiguities in the interpretation of trace results.
METHOD
We collected repeated Kato-Katz egg counts from 210 school-aged children and scored POC-CCA tests according to the manufacturer's guidelines (referred to from here as POC-CCA+) and the externally developed G score. We used hidden Markov models parameterized with Kato-Katz; Kato-Katz and POC-CCA+; and Kato-Katz and G-Scores, inferring latent clearance and reinfection probabilities at four timepoints over six-months through a more formal statistical reconciliation of these diagnostics than previously conducted. Our approach required minimal but robust assumptions regarding trace interpretations.
RESULTS
Antigen-based models estimated higher infection prevalence across all timepoints compared with the Kato-Katz model, corresponding to lower clearance and higher reinfection estimates. Specifically, pre-treatment prevalence estimates were 85% (Kato-Katz; 95% CI: 79%-92%), 99% (POC-CCA+; 97%-100%) and 98% (G-Score; 95%-100%). Post-treatment, 93% (Kato-Katz; 88%-96%), 72% (POC-CCA+; 64%-79%) and 65% (G-Score; 57%-73%) of those infected were estimated to clear infection. Of those who cleared infection, 35% (Kato-Katz; 27%-42%), 51% (POC-CCA+; 41%-62%) and 44% (G-Score; 33%-55%) were estimated to have been reinfected by 9-weeks.
CONCLUSIONS
Treatment impact was shorter-lived than Kato-Katz-based estimates alone suggested, with lower clearance and rapid reinfection. At 3 weeks after treatment, longer-term clearance dynamics are captured. At 9 weeks after treatment, reinfection was captured, but failed clearance could not be distinguished from rapid reinfection. Therefore, frequent sampling is required to understand these important epidemiological dynamics.
Topics: Animals; Antigens, Helminth; Child; Feces; Humans; Prevalence; Reinfection; Schistosoma mansoni; Schistosomiasis mansoni; Sensitivity and Specificity
PubMed: 34358299
DOI: 10.1093/cid/ciab679 -
Infectious Diseases of Poverty Apr 2018The speedy rate of change in the environmental and socio-economics factors may increase the incidence, prevalence and risk of schistosomiasis infections in Zambia.... (Review)
Review
BACKGROUND
The speedy rate of change in the environmental and socio-economics factors may increase the incidence, prevalence and risk of schistosomiasis infections in Zambia. However, available information does not provide a comprehensive understanding of the biogeography and distribution of the disease, ecology and population dynamics of intermediate host snails. The current study used an information-theoretical approach to understand the biogeography and prevalence schistosomiasis and identified knowledge gaps that would be useful to improve policy towards surveillance and eradication of intermediate hosts snails in Zambia.
METHODS
To summarise the existing knowledge and build on past and present experiences of schistosomiasis epidemiology for effective disease control in Zambia, a systematic search of literature for the period 2000-2017 was done on PubMed, Google Scholar and EBSCOhost. Using the key words: 'Schistosomiasis', 'Biomphalaria', 'Bulinus', 'Schistosoma mansoni', 'Schistosoma haematobium', and 'Zambia', in combination with Booleans terms 'AND' and 'OR', published reports/papers were obtained and reviewed independently for inclusion.
RESULTS
Thirteen papers published in English that fulfilled the inclusion criteria were selected for the final review. The papers suggest that the risk of infection has increased over the years and this has been attributed to environmental, socio-economic and demographic factors. Furthermore, schistosomiasis is endemic in many parts of the country with infection due to Schistosoma haematobium being more prevalent than that due to S. mansoni. This review also found that S. haematobium was linked to genital lesions, thus increasing risks of contracting other diseases such as HIV and cervical cancer.
CONCLUSIONS
For both S. haematobium and S. mansoni, environmental, socio-economic, and demographic factors were influential in the transmission and prevalence of the disease and highlight the need for detailed knowledge on ecological modelling and mapping the distribution of the disease and intermediate host snails for effective implementation of control strategies.
Topics: Animals; Humans; Prevalence; Schistosoma haematobium; Schistosoma mansoni; Schistosomiasis haematobia; Schistosomiasis mansoni; Socioeconomic Factors; Zambia
PubMed: 29706131
DOI: 10.1186/s40249-018-0424-5 -
Tropical Medicine & International... Sep 2020To perform a descriptive analysis of the activities of the Schistosomiasis Control Program, as well as the spatial distribution of the condition in the state of Alagoas,...
OBJECTIVE
To perform a descriptive analysis of the activities of the Schistosomiasis Control Program, as well as the spatial distribution of the condition in the state of Alagoas, Brazil, for the period from 2007 to 2016.
METHODS
Descriptive ecological study. Data from positive human cases and operational data were collected in the Information System of the Schistosomiasis Control Program, and data for spatial analysis were collected on the website of the Brazilian Institute of Geography and Statistics. An analysis of spatial autocorrelation (Moran statistics) was performed, where a spatial pattern was established, which showed the Q1 and Q2 patterns to be the most important, and Q3 and Q4 representing transition areas.
RESULTS
In the years under study, at least 85% (n = 60/70) of the municipalities carried out the activities recommended by the PCE (Schistosomiasis Control Program). Alagoas presented an average positivity rate of 7.1%, which is very high compared to the prevalence of 3.3% at the last national schistosomiasis survey conducted between 2010 and 2015. Moran's statistics showed 22/70 municipalities forming a Q1 cluster, of high/high pattern, and 32/70 municipalities forming a Q2 cluster, of low/low pattern, with the others in a transition area. Moran Map data, however, showed only 7/70 municipalities in the endemic area with a spatial autocorrelation, with these municipalities having the Mundau River as a common element.
CONCLUSION
Schistosomiasis mansoni is of great importance for public health in Alagoas and that the use of spatial analysis can identify priority areas for preventive and control measures against schistosomiasis mansoni.
Topics: Animals; Brazil; Humans; Prevalence; Risk Factors; Schistosoma mansoni; Schistosomiasis mansoni; Spatial Analysis
PubMed: 32633066
DOI: 10.1111/tmi.13458 -
Revista Da Sociedade Brasileira de... 2014Different aspects of hepatosplenic schistosomiasis are revisited here. Manson's schistosomiasis causes periportal fibrosis and portal hypertension in approximately 6% of... (Review)
Review
Different aspects of hepatosplenic schistosomiasis are revisited here. Manson's schistosomiasis causes periportal fibrosis and portal hypertension in approximately 6% of infected subjects, usually with preservation of their hepatic function. The assessment of liver involvement is of major importance in determining the prognosis and risk of complications from schistosomiasis, such as upper digestive bleeding secondary to variceal rupture. For many years, the diagnosis of hepatosplenic schistosomiasis and liver fibrosis was made by abdominal palpation and the finding of liver and/or spleen enlargement. However, there is no consensus regarding the clinical parameters of the liver and spleen to be considered in this physical evaluation. For the last three decades, abdominal ultrasound (US) has become the best imaging technique to evaluate liver fibrosis caused by schistosomiasis mansoni. However, US is a subjective procedure and is therefore examiner-dependent. Magnetic resonance imaging (MRI) findings have provided valuable information in addition to ultrasound and clinical examination. The combination of a comprehensive history and physical examination, basic laboratory tests (a stool examination for Schistosoma mansoni eggs and a blood cell count), biomarkers for liver fibrosis/portal hypertension and imaging methods seem to offer the best approach for evaluating patients with this disease. In situations where research is involved or in patients with severe disease, MRI may be considered.
Topics: Animals; Biomarkers; Feces; Humans; Liver Diseases, Parasitic; Magnetic Resonance Imaging; Schistosomiasis mansoni; Severity of Illness Index; Splenic Diseases; Ultrasonography
PubMed: 24861284
DOI: 10.1590/0037-8682-0186-2013