title: The evolving threat of influenza viruses of animal origin and the challenges in developing appropriate diagnostics.
abstract: BACKGROUND
  An H1N1 subtype of swine origin caused the first influenza pandemic in this century. This pandemic strain was a reassortant of avian, swine, and human influenza viruses. Many diagnostic laboratories were overwhelmed by the testing demands related to this pandemic. Nevertheless, there remains the threat of other animal influenza viruses, such as highly pathogenic H5N1. As a part of pandemic preparedness, it is essential to identify the diagnostic challenges that will accompany the next pandemic.
  
  
  BACKGROUND
  We discuss the natural reservoir of influenza viruses and the possible role of livestock in the emergence of pandemic strains. The current commonly used molecular tests for influenza diagnosis or surveillance are also briefly reviewed. Some of these approaches are also used to detect animal viruses. Unfortunately, owing to a lack of systematic surveillance of animal influenza viruses, established tests may not be able to detect pandemic strains that have yet to emerge from the animal reservoir. Thus, multiple strategies need to be developed for better identification of influenza viruses. In addition, molecular assays for detection of mutations associated with antiviral resistance and for viral segment reassortments should also be encouraged.
  
  
  CONCLUSIONS
  Influenza viruses are highly dynamic viruses. Regular and systematic influenza surveillance in both humans and animals is essential to provide a more comprehensive picture of the prevalent influenza viruses. To better prepare for the next pandemic, we should develop some simple and easy-to-use tests for characterizing newly emerging influenza viruses.
authors.affiliation: Centre of Influenza Research and School of Public Health, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China.
authors.forename: Polly W Y
authors.initials: PW
authors.lastname: Mak
authors.forename: Shanthi
authors.initials: S
authors.lastname: Jayawardena
authors.forename: Leo L M
authors.initials: LL
authors.lastname: Poon
mesh_terms: D000818:Animals; D019411:Clinical Laboratory Techniques / Q000379:methods; D003140:Communicable Disease Control; D004196:Disease Outbreaks / Q000517:prevention & control; D004197:Disease Reservoirs; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000502:physiology; D007251:Influenza, Human / Q000175:diagnosis / Q000635:transmission / Q000821:virology; D058751:Livestock / Q000821:virology; D009975:Orthomyxoviridae / Q000302:isolation & purification; D009976:Orthomyxoviridae Infections / Q000175:diagnosis / Q000635:transmission / Q000662:veterinary* / Q000821:virology; D014773:Virology / Q000379:methods; D015047:Zoonoses