title: Seroepidemiology of selected arboviruses in febrile patients visiting selected health facilities in the lake/river basin areas of Lake Baringo, Lake Naivasha, and Tana River, Kenya.
abstract: BACKGROUND
  Arboviruses cause emerging and re-emerging infections affecting humans and animals. They are spread primarily by blood-sucking insects such as mosquitoes, ticks, midges, and sandflies. Changes in climate, ecology, demographic, land-use patterns, and increasing global travel have been linked to an upsurge in arboviral disease. Outbreaks occur periodically followed by persistent low-level circulation.
  
  
  OBJECTIVE
  This study was undertaken to determine the seroepidemiology of selected arboviruses among febrile patients in selected lake/river basins of Kenya.
  
  
  METHODS
  Using a hospital-based cross-sectional descriptive survey, febrile patients were recruited and their serum samples tested for exposure to immunoglobulin M (IgM) and IgG antibodies against Crimean-Congo hemorrhagic fever virus (CCHFV), Rift Valley fever virus (RVFV), West Nile virus (WNV), and chikungunya virus (CHIKV). Samples positive for CHIKV and WNV were further confirmed by the plaque reduction neutralization test (PRNT).
  
  
  RESULTS
  Of the 379 samples examined, 176 were IgG positive for at least one of these arboviruses (46.4%, 95% confidence interval [CI] 41.4-51.5%). Virus-specific prevalence for CCHF, RVF, WN, and CHIK was 25.6%, 19.5%, 12.4%, and 2.6%, respectively. These prevalences varied significantly with geographical site (p<0.001), with Tana recording the highest overall arboviral seropositivity. PRNT results for Alphaviruses confirmed that the actual viruses circulating in Baringo were Semliki Forest virus (SFV) and CHIKV, o'nyong nyong virus (ONNV) in Naivasha, and SFV and Sindbis virus (SINDV) in Tana delta. Among the flaviviruses tested, WNV was circulating in all the three sites.
  
  
  CONCLUSIONS
  There is a high burden of febrile illness in humans due to CCHFV, RVFV, WNV, and CHIKV infection in the river/lake basin regions of Kenya.
authors.affiliation: 1 International Centre of Insect Physiology and Ecology , Nairobi, Kenya .
authors.forename: Caroline
authors.initials: C
authors.lastname: Tigoi
authors.forename: Olivia
authors.initials: O
authors.lastname: Lwande
authors.forename: Benedict
authors.initials: B
authors.lastname: Orindi
authors.forename: Zephania
authors.initials: Z
authors.lastname: Irura
authors.forename: Juliette
authors.initials: J
authors.lastname: Ongus
authors.forename: Rosemary
authors.initials: R
authors.lastname: Sang
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D001102:Arbovirus Infections / Q000453:epidemiology* / Q000821:virology; D001103:Arboviruses / Q000276:immunology; D065632:Chikungunya Fever / Q000453:epidemiology* / Q000821:virology; D002646:Chikungunya virus / Q000276:immunology; D003430:Cross-Sectional Studies; D005260:Female; D005334:Fever; D006268:Health Facilities; D003225:Hemorrhagic Fever Virus, Crimean-Congo / Q000276:immunology; D006479:Hemorrhagic Fever, Crimean / Q000453:epidemiology* / Q000821:virology; D006801:Humans; D007630:Kenya / Q000453:epidemiology; D060106:Lakes; D008297:Male; D012295:Rift Valley Fever / Q000453:epidemiology* / Q000821:virology; D012296:Rift Valley fever virus / Q000276:immunology; D045483:Rivers; D016036:Seroepidemiologic Studies; D014901:West Nile Fever / Q000453:epidemiology* / Q000821:virology; D014902:West Nile virus / Q000276:immunology
chemical_list: D000914:Antibodies, Viral
keywords: Arboviruses; Chikungunya virus; Crimean–Congo hemorrhagic fever virus; Febrile patients; Kenya; Lake/River Basin areas; Rift Valley fever virus; West Nile virus