title: Epidemiological Interactions between Urogenital and Intestinal Human Schistosomiasis in the Context of Praziquantel Treatment across Three West African Countries.
abstract: 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.
  
  
  RESULTS
  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
  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.
authors.affiliation: Department of Infectious Disease Epidemiology, Imperial College London, St. Mary's Campus, London, United Kingdom; Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot, Berkshire, United Kingdom.
authors.forename: Sarah C L
authors.initials: SC
authors.lastname: Knowles
authors.affiliation: Department of Infectious Disease Epidemiology, Imperial College London, St. Mary's Campus, London, United Kingdom; Natural History Museum, Parasites and Vectors Division, Department of Life Sciences, London, United Kingdom.
authors.forename: Bonnie L
authors.initials: BL
authors.lastname: Webster
authors.affiliation: Réseau International Schistosomose, Environnement, Aménagement et Lutte (RISEAL), Niamey, Niger.
authors.forename: Amadou
authors.initials: A
authors.lastname: Garba
authors.affiliation: Institut National de Recherche en Santé Publique (INRSP), Ministère de la Santé, Bamako, Mali.
authors.forename: Moussa
authors.initials: M
authors.lastname: Sacko
authors.affiliation: Institut Sénégalais de Recherches Agricoles (ISRA), Bel Air, Dakar, Sénégal.
authors.forename: Oumar T
authors.initials: OT
authors.lastname: Diaw
authors.affiliation: Department of Infectious Disease Epidemiology, Imperial College London, St. Mary's Campus, London, United Kingdom.
authors.forename: Alan
authors.initials: A
authors.lastname: Fenwick
authors.affiliation: Natural History Museum, Parasites and Vectors Division, Department of Life Sciences, London, United Kingdom.
authors.forename: David
authors.initials: D
authors.lastname: Rollinson
authors.affiliation: Department of Infectious Disease Epidemiology, Imperial College London, St. Mary's Campus, London, United Kingdom; Department of Pathology and Pathogen Biology, Centre for Emerging, Endemic and Exotic Diseases (CEEED), Royal Veterinary College, University of London, London, United Kingdom.
authors.forename: Joanne P
authors.initials: JP
authors.lastname: Webster
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use*; D060085:Coinfection / Q000188:drug therapy* / Q000469:parasitology; D005260:Female; D006801:Humans; D008297:Male; D011223:Praziquantel / Q000627:therapeutic use*; D012553:Schistosomiasis haematobia / Q000188:drug therapy* / Q000469:parasitology; D012555:Schistosomiasis mansoni / Q000188:drug therapy* / Q000469:parasitology
chemical_list: D000871:Anthelmintics; D011223:Praziquantel