title: Low Usutu virus seroprevalence in four zoological gardens in central Europe.
abstract: BACKGROUND
  Usutu virus (USUV), a mosquito-borne flavivirus of the Japanese encephalitis virus antigenic group, caused bird die-offs in Austria, Hungary and Switzerland between 2001 and 2009. While the zoological gardens of Vienna and Zurich recorded USUV-associated mortality in different species of birds during this period, incidences in Budapest were limited to areas outside the zoo, and in the greater Basel area avian mortality due to USUV infection was not observed at all. The objectives of this investigation were to gain insight into USUV infection dynamics in captive birds in zoos with varying degrees of virus exposure and to study differences in susceptibility to USUV of different species of birds.
  
  
  RESULTS
  372 bird sera were collected between October 2006 and August 2007. The samples were tested in parallel by hemagglutination inhibition (HI) and 90% plaque reduction neutralization tests (PRNT-90). 8.75%, 5.3% and 6.59% of birds in the zoos of Vienna, Zurich and Basel, respectively, showed USUV-specific antibodies by PRNT-90. No antibodies to USUV were detected in birds of the Budapest zoo. The order Strigiformes (owls) exhibited the highest USUV-seroprevalence, compared to other orders of birds.
  
  
  CONCLUSIONS
  USUV seems not to pose an imminent threat to zoo bird populations in central Europe at the moment. Depending on a variety of especially environmental factors, however, this may change at any time in the (near) future, as experienced with West Nile virus (WNV). It is therefore strongly suggested to continue with combined WNV and USUV surveillance activities in affected areas.
authors.affiliation: Viral Zoonoses, Emerging and Vector-Borne Infections Group, Institute of Virology, University of Veterinary Medicine Vienna, Vienna, Austria.
authors.forename: Nicola
authors.initials: N
authors.lastname: Buchebner
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Zenker
authors.forename: Christian
authors.initials: C
authors.lastname: Wenker
authors.forename: Hanspeter W
authors.initials: HW
authors.lastname: Steinmetz
authors.forename: Endre
authors.initials: E
authors.lastname: Sós
authors.forename: Helga
authors.initials: H
authors.lastname: Lussy
authors.forename: Norbert
authors.initials: N
authors.lastname: Nowotny
mesh_terms: D000818:Animals; D000836:Animals, Zoo / Q000097:blood / Q000821:virology*; D000914:Antibodies, Viral / Q000097:blood; D001317:Austria / Q000453:epidemiology; D001715:Bird Diseases / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology*; D001717:Birds; D018349:Encephalitis Viruses, Japanese / Q000276:immunology / Q000302:isolation & purification*; D018177:Flavivirus Infections / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000662:veterinary*; D006814:Hungary / Q000453:epidemiology; D016036:Seroepidemiologic Studies; D013557:Switzerland / Q000453:epidemiology
chemical_list: D000914:Antibodies, Viral
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