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Knowles S.C.L.,Imperial College London | Webster B.L.,Imperial College London | Webster B.L.,Natural History Museum in London | Garba A.,Reseau International Schistosomose | And 6 more authors.
PLoS Neglected Tropical Diseases | Year: 2015

Background: In many parts of sub-Saharan Africa, urogenital and intestinal schistosomiasis co-occur, and mixed species infections containing both Schistosoma haematobium and S. mansoni can be common. During co-infection, interactions between these two species are possible, yet the extent to which such interactions influence disease dynamics or the outcome of control efforts remains poorly understood. Methodology/Principal Findings: Here we analyse epidemiological data from three West African countries co-endemic for urogenital and intestinal schistosomiasis (Senegal, Niger and Mali) to test whether the impact of praziquantel (PZQ) treatment, subsequent levels of re-infection or long-term infection dynamics are altered by co-infection. In all countries, positive associations between the two species prevailed at baseline: infection by one species tended to predict infection intensity for the other, with the strength of association varying across sites. Encouragingly, we found little evidence that co-infection influenced PZQ efficacy: species-specific egg reduction rates (ERR) and cure rates (CR) did not differ significantly with co-infection, and variation in treatment success was largely geographical. In Senegal, despite positive associations at baseline, children with S. mansoni co-infection at the time of treatment were less intensely re-infected by S. haematobium than those with single infections, suggesting competition between the species may occur post-treatment. Furthermore, the proportion of schistosome infections attributable to S. mansoni increased over time in all three countries examined. Conclusions/Significance: These findings suggest that while co-infection between urinary and intestinal schistosomes may not directly affect PZQ treatment efficacy, competitive interspecific interactions may influence epidemiological patterns of re-infection post-treatment. While re-infection patterns differed most strongly according to geographic location, interspecific interactions also seem to play a role, and could cause the community composition in mixed species settings to shift as disease control efforts intensify, a situation with implications for future disease management in this multi-species system. © 2015 Knowles et al.


Mansour W.,Angers University Hospital Center | Mansour W.,Laboratoire HIFIH | Bollahi M.-A.,Sanguine | Hamed C.-T.,Sanguine | And 9 more authors.
Journal of Clinical Virology | Year: 2012

Background: In Mauritania, some authors have described a possible high prevalence of hepatitis delta virus (HDV) infection in the 1990s in studies of small-size samples. Objectives: The aims of our study were to assess the prevalence of HDV in HBsAg positive blood donors in Mauritania, to identify the main risk factors for HDV transmission and to analyze genetic diversity of HDV strains. Study design: From October 2008 to December 2009, 11,100 consecutive blood donors were considered in this study. Among them, 1700 (15.3%) were HBsAg positive and 455 accepted to participate in this study. Demographic, epidemiological, ethnical, clinical and biological data were recorded. HDV screening, i.e., antibodies (HDVAb) and RNA (HDV-RNA) detection, was performed for all of them as well as HDV and HBV genotyping. Results: Ninety/455 (19.78%) donors were HDVAb positive and HDV-RNA was detectable in 56 (62.2%) of them. HDV infection was significantly associated with older age, number of marriages, military profession, residence in the desert and a history of hospitalization. The HDV genotypes of the circulating strains were HDV-1 (89.3%) and HDV-5 (10.7%). Conclusion: HDV is highly endemic in Mauritanian blood donors indicating that a high number of them will develop chronic hepatitis, cirrhosis or hepatocellular carcinoma. Associated risk factors support nosocomial transmission of HDV. These data underline the need to reinforce HBV vaccination in newborns and in blood donors without HBV markers, together with screening for HDV in HBV-infected individuals. © 2012 Elsevier B.V.


Caugant D.A.,Norwegian Institute of Public Health | Caugant D.A.,University of Oslo | Kristiansen P.A.,Norwegian Institute of Public Health | Wang X.,Centers for Disease Control and Prevention | And 7 more authors.
PLoS ONE | Year: 2012

Background: The serogroup A conjugate meningococcal vaccine, MenAfriVac, was introduced in mass vaccination campaigns in December 2010 in Burkina Faso, Mali and Niger. In the coming years, vaccination will be extended to other African countries at risk of epidemics. To document the molecular characteristics of disease-causing meningococcal strains circulating in the meningitis belt of Africa before vaccine introduction, the World Health Organization Collaborating Centers on Meningococci in Europe and United States established a common strain collection of 773 isolates from cases of invasive meningococcal disease collected between 2004 and 2010 from 13 sub-Saharan countries. Methodology: All isolates were characterized by multilocus sequence typing, and 487 (62%) were also analyzed for genetic variation in the surface antigens PorA and FetA. Antibiotic susceptibility was tested for part of the collection. Principal Findings: Only 19 sequence types (STs) belonging to 6 clonal complexes were revealed. ST-5 clonal complex dominated with 578 (74.8%) isolates. All ST-5 complex isolates were remarkably homogeneous in their PorA (P1.20,9) and FetA (F3-1) and characterized the serogroup A strains which have been responsible for most epidemics during this time period. Sixty-eight (8.8%) of the 773 isolates belonged to the ST-11 clonal complex which was mainly represented by serogroup W135, while an additional 38 (4.9%) W135 isolates belonged to the ST-175 complex. Forty-eight (6.2%) serogroup X isolates from West Africa belonged to the ST-181 complex, while serogroup X cases in Kenya and Uganda were caused by an unrelated clone, ST-5403. Serogroup X, ST-181, emerged in Burkina Faso before vaccine introduction. Conclusions: In the seven years preceding introduction of a new serogroup A conjugate vaccine, serogroup A of the ST-5 clonal complex was identified as the predominant disease-causing strain.


Tandina F.,Pathologie humaine | Doumbo S.N.,University Des Science Techniques Et Technologiques Of Bamako Usttb | Kone A.K.,University Des Science Techniques Et Technologiques Of Bamako Usttb | Guindo D.,University Des Science Techniques Et Technologiques Of Bamako Usttb | And 5 more authors.
Medecine et Sante Tropicales | Year: 2016

Objective: The objective of this work was to describe the epidemiology of schistosomiasis 10 years after mass administration of praziquantel began in Sotuba, Mali. Methodology/ Results: This observational cross-sectional survey in Sotuba, a periurban village in the Bamako district, took place from July to September 2010 and collected stool and urine samples from residents at least one year old. Kato-Katz (for stool) and urine filtration techniques were used to detect Schistosoma mansoni and S. hæmatobium eggs, respectively. Overall, 335 urine samples and 300 stool samples were examined. The prevalence rate was 5.4% (18/335) for S. hæmatobium and 8.7% (26/ 300) for S. mansoni. Excretion of these eggs was most frequent in the 6-15 year-old group: 4.8% (16/ 335) for S. hæmatobium and 7.7% (23/300) for S. mansoni. Snails of the Biomphalaria pfeifferi and Bulinus truncatus species were the intermediate hosts, captured in the fields at water contact points. The principal clinical symptoms reported by participants were abdominal pain 27.2% (61/169) and headaches 23.2% (52/169). Conclusion: Despite the implementation of mass drug administration in Mali a decade ago, our results show that schistosomiasis transmission continues in Sotuba. Assessment of the risk factors for this persistent transmission is strongly needed. © 2016 JLE.


Grant
Agency: Cordis | Branch: FP7 | Program: CP-FP-SICA | Phase: HEALTH.2010.2.3.4-2 | Award Amount: 6.45M | Year: 2010

Neglected Infectious Diseases (NID) such as trypanosomiasis, leishmaniasis, schistosomiasis and soil-transmitted helminthiasis receive less than 5% of the global investment for tropical diseases research. Clinical praxis in disease-endemic countries (DEC) is rarely evidence based and does not make use of the latest innovations in diagnostic technology. NIDrelated research on diagnostics is particularly underfunded, and diagnostic tools are lacking for a number of NID. The aim of this proposal is to bridge the gap between existing technological innovation in diagnostics and clinical care practice for NID in resource-poor settings. The specific objectives are to develop simple, cost-effective diagnosis-treatment algorithms for three NID-related clinical syndromes: the persistent fever, the neurological and the digestive syndromes. Evidence-based algorithms for the primary care level will be designed with a patient-centred approach, following guidance from DEC stakeholders and making the best possible use of existing assays and treatments. Relevant diagnostic technology and diagnostic platforms will be introduced according to the specific epidemiological contexts in Africa and South-Asia. The research consortium brings together a network of clinical epidemiologists, a diagnostics development group, several partners from academia and SMEs. The consortium further includes workpackages on reference laboratory, economic evaluation, quality assurance and translation to policy. By developing accurate and affordable diagnostic platforms and by optimizing diagnostic-treatment algorithms, this project will rationalise treatment use, circumvent progression to severe presentations and thereby reduce NID morbidity/mortality and hinder the emergence of resistances. The project will result in two main deliverables: policy recommendation for health authorities in DEC, and a series of innovative diagnostic platforms.

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