title: Seroprevalence of alphavirus antibodies in a cross-sectional study in southwestern Tanzania suggests endemic circulation of chikungunya.
abstract: BACKGROUND
  To date, Alphavirus infections and their most prominent member, chikungunya fever, a viral disease which first became apparent in Tanzania in 1953, have been very little investigated in regions without epidemic occurrence. Few data exist on burden of disease and socio-economic and environmental covariates disposing to infection.
  
  
  METHODS
  A cross-sectional seroprevalence study was undertaken in 1,215 persons from Mbeya region, South-Western Tanzania, to determine the seroprevalence of anti-Alphavirus IgG antibodies, and to investigate associated risk factors.
  
  
  RESULTS
  18% of 1,215 samples were positive for Alphavirus IgG. Seropositivity was associated with participant age, low to intermediate elevation, flat terrain and with IgG positivity for Rift Valley fever, Flaviviridae, and rickettsiae of the spotted fever group. When comparing the geographical distribution of Alphavirus seropositivity to that of Rift Valley fever, it was obvious that Alphaviruses had spread more widely throughout the study area, while Rift Valley fever was concentrated along the shore of Lake Malawi.
  
  
  CONCLUSIONS
  Alphavirus infections may contribute significantly to the febrile disease burden in the study area, and are associated with several arthropod-borne infections. Their spread seems only limited by factors affecting mosquitoes, and seems less restricted than that of Rift Valley fever.
authors: Division of Infectious Diseases and Tropical Medicine, Medical Centre of the University of Munich (LMU), Munich, Germany.
authors: Nina
authors: N
authors: Weller
authors: National Institute for Medical Research -Mbeya Medical Research Center, Mbeya, Tanzania.
authors: Petra
authors: P
authors: Clowes
authors: Bundeswehr Institute of Microbiology, Munich, Germany; German Center for Infection Research (DZIF), partner site Munich, Munich, Germany.
authors: Gerhard
authors: G
authors: Dobler
authors: Division of Infectious Diseases and Tropical Medicine, Medical Centre of the University of Munich (LMU), Munich, Germany; German Center for Infection Research (DZIF), partner site Munich, Munich, Germany.
authors: Elmar
authors: E
authors: Saathoff
authors: Division of Infectious Diseases and Tropical Medicine, Medical Centre of the University of Munich (LMU), Munich, Germany; National Institute for Medical Research -Mbeya Medical Research Center, Mbeya, Tanzania.
authors: Inge
authors: I
authors: Kroidl
authors: National Institute for Medical Research -Mbeya Medical Research Center, Mbeya, Tanzania.
authors: Nyanda Elias
authors: NE
authors: Ntinginya
authors: National Institute for Medical Research -Mbeya Medical Research Center, Mbeya, Tanzania.
authors: Leonard
authors: L
authors: Maboko
authors: Division of Infectious Diseases and Tropical Medicine, Medical Centre of the University of Munich (LMU), Munich, Germany.
authors: Thomas
authors: T
authors: Löscher
authors: Division of Infectious Diseases and Tropical Medicine, Medical Centre of the University of Munich (LMU), Munich, Germany; National Institute for Medical Research -Mbeya Medical Research Center, Mbeya, Tanzania; German Center for Infection Research (DZIF), partner site Munich, Munich, Germany.
authors: Michael
authors: M
authors: Hoelscher
authors: Division of Infectious Diseases and Tropical Medicine, Medical Centre of the University of Munich (LMU), Munich, Germany; German Center for Infection Research (DZIF), partner site Munich, Munich, Germany.
authors: Norbert
authors: N
authors: Heinrich
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000524:Alphavirus / Q000276:immunology*; D018354:Alphavirus Infections / Q000453:epidemiology*; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D013636:Tanzania / Q000453:epidemiology; D019371:Topography, Medical; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G