title: An inverse association between West Nile virus serostatus and avian malaria infection status.
abstract: BACKGROUND
  Various ecological and physiological mechanisms might influence the probability that two or more pathogens may simultaneously or sequentially infect a host individual. Concurrent infections can have important consequences for host condition and fitness, including elevated mortality risks. In addition, interactions between coinfecting pathogens may have important implications for transmission dynamics.
  
  
  METHODS
  Here, we explore patterns of association between two common avian pathogens (West Nile virus and avian malaria parasites) among a suburban bird community in Chicago, IL, USA that share mosquito vectors. We surveyed 1714 individual birds across 13 species for both pathogens through established molecular protocols.
  
  
  RESULTS
  Field investigations of haemosporidian and West Nile virus (WNV) infections among sampled birds yielded an inverse association between WNV serostatus and Plasmodium infection status. This relationship occurred in adult birds but not in juveniles. There was no evidence for a relationship between Haemoproteus infection and WNV serostatus. We detected similar prevalence of Plasmodium among birds captured with active WNV infections and spatiotemporally paired WNV-naïve individuals of the same species, demonstrating that the two pathogens can co-infect hosts.
  
  
  CONCLUSIONS
  Mechanisms explaining the negative association between WNV serostatus and Plasmodium infection status remain unclear and must be resolved through experimental infection procedures. However, our results highlight potential interactions between two common avian pathogens that may influence their transmission among hosts. This is especially relevant considering that West Nile virus is a common zoonotic pathogen with public health implications. Moreover, both pathogens are instructive models in infectious disease ecology, and infection with either has fitness consequences for their avian hosts.
authors.affiliation: Department of Biology, University of Missouri-St, Louis, One University Boulevard, St, Louis, MO 63121, USA. mcmn92@umsl.edu.
authors.forename: Matthew C I
authors.initials: MC
authors.lastname: Medeiros
authors.forename: Tavis K
authors.initials: TK
authors.lastname: Anderson
authors.forename: Jenni M
authors.initials: JM
authors.lastname: Higashiguchi
authors.forename: Uriel D
authors.initials: UD
authors.lastname: Kitron
authors.forename: Edward D
authors.initials: ED
authors.lastname: Walker
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Brawn
authors.forename: Bethany L
authors.initials: BL
authors.lastname: Krebs
authors.forename: Marilyn O
authors.initials: MO
authors.lastname: Ruiz
authors.forename: Tony L
authors.initials: TL
authors.lastname: Goldberg
authors.forename: Robert E
authors.initials: RE
authors.lastname: Ricklefs
authors.forename: Gabriel L
authors.initials: GL
authors.lastname: Hamer
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001715:Bird Diseases / Q000097:blood* / Q000453:epidemiology / Q000469:parasitology / Q000821:virology; D001717:Birds; D060085:Coinfection / Q000469:parasitology / Q000662:veterinary / Q000821:virology; D007087:Illinois / Q000453:epidemiology; D008289:Malaria, Avian / Q000097:blood* / Q000453:epidemiology; D012307:Risk Factors; D014901:West Nile Fever / Q000097:blood / Q000453:epidemiology / Q000662:veterinary*; D014902:West Nile virus / Q000302:isolation & purification*
chemical_list: D000914:Antibodies, Viral