title: Ecological Drivers of Mansonella perstans Infection in Uganda and Patterns of Co-endemicity with Lymphatic Filariasis and Malaria.
abstract: BACKGROUND
  Mansonella perstans is a widespread, but relatively unknown human filarial parasite transmitted by Culicoides biting midges. Although it is found in many parts of sub-Saharan Africa, only few studies have been carried out to deepen the understanding of its ecology, epidemiology, and health consequences. Hence, knowledge about ecological drivers of the vector and parasite distribution, integral to develop spatially explicit models for disease prevention, control, and elimination strategies, is limited.
  
  
  METHODS
  We analyzed data from a comprehensive nationwide survey of M. perstans infection conducted in 76 schools across Uganda in 2000-2003, to identify environmental drivers. A suite of Bayesian geostatistical regression models was fitted, and the best fitting model based on the deviance information criterion was utilized to predict M. perstans infection risk for all of Uganda. Additionally, we investigated co-infection rates and co-distribution with Wuchereria bancrofti and Plasmodium spp. infections observed at the same survey by mapping geographically overlapping areas.
  
  
  RESULTS
  Several bioclimatic factors were significantly associated with M. perstans infection levels. A spatial Bayesian regression model showed the best fit, with diurnal temperature range, normalized difference vegetation index, and cattle densities identified as significant covariates. This model was employed to predict M. perstans infection risk at non-sampled locations. The level of co-infection with W. bancrofti was low (0.3%), due to limited geographic overlap. However, where the two infections did overlap geographically, a positive association was found.
  
  
  CONCLUSIONS
  This study presents the first geostatistical risk map for M. perstans in Uganda. We confirmed a widespread distribution of M. perstans, and identified important potential drivers of risk. The results provide new insight about the ecologic preferences of this otherwise poorly known filarial parasite and its Culicoides vector species in Uganda, which might be relevant for other settings in sub-Saharan Africa.
authors.affiliation: Center for Macroecology, Evolution and Climate, The Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anna-Sofie
authors.initials: AS
authors.lastname: Stensgaard
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.|University of Basel, Basel, Switzerland.
authors.forename: Penelope
authors.initials: P
authors.lastname: Vounatsou
authors.affiliation: Envision/NTD Program, RTI, Kampala, Uganda.
authors.forename: Ambrose W
authors.initials: AW
authors.lastname: Onapa
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland.|University of Basel, Basel, Switzerland.
authors.forename: Jürg
authors.initials: J
authors.lastname: Utzinger
authors.affiliation: Department of Veterinary Disease Biology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Erling M
authors.initials: EM
authors.lastname: Pedersen
authors.affiliation: Department of Veterinary Disease Biology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Kristensen
authors.affiliation: Department of Veterinary Disease Biology, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Paul E
authors.initials: PE
authors.lastname: Simonsen
mesh_terms: D000293:Adolescent; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000469:parasitology; D002648:Child; D002675:Child, Preschool; D017753:Ecosystem; D004605:Elephantiasis, Filarial / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008288:Malaria / Q000453:epidemiology*; D008297:Male; D008366:Mansonella / Q000502:physiology*; D008368:Mansonelliasis / Q000453:epidemiology* / Q000469:parasitology / Q000662:veterinary*; D014454:Uganda / Q000453:epidemiology; D055815:Young Adult