title: Avian influenza--a new challenge.
abstract: OBJECTIVE
  To present a wide-ranging review of the literature on avian influenza A (H5N1).
  
  
  BACKGROUND
  The recent epidemics caused by the avian influenza A virus in Asia, have demonstrated the capacity of this agent to cause serious illness in humans.
  
  
  METHODS
  Most articles were obtained from the Medline database using the keywords "Influenza A virus", "avian flu", "epidemiology", "disease vectors" and "H5N1 infection" for the period between 1996 and 2006.
  
  
  RESULTS
  We selected 25 original articles addressing the recent outbreaks of infection with the H5N1 subtype of avian influenza A in domesticated birds in Asia, which have resulted in significant economic losses and repercussions for public health, as well as some cases of human infection presenting high lethality. In most cases, infection has been associated with direct exposure to infected birds or contact with surfaces infected with bird excrement. However, cases of human-to-human transmission have been confirmed.
  
  
  CONCLUSIONS
  Controlling outbreaks in domestic fowl and limiting contact between humans and infected birds must be the priorities in the management of this disease at the public health level. In addition, techniques and knowledge regarding the disease should be widely disseminated (Ref: 28).
authors.affiliation: Escola Superior de Saúde do Campus Universitário Jean Piaget de Viseu, Lordosa, Portugal. carloslaranjeira@hotmail.com
authors.forename: C A
authors.initials: CA
authors.lastname: Laranjeira
mesh_terms: D000818:Animals; D001717:Birds; D004196:Disease Outbreaks / Q000662:veterinary; D006801:Humans; D053124:Influenza A Virus, H5N1 Subtype; D005585:Influenza in Birds / Q000175:diagnosis / Q000453:epidemiology*; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology* / Q000628:therapy / Q000635:transmission