[Influenza A(H5N1) in Hong Kong: forerunner of a pandemic or an only scientifically interesting phenomenon and a useful exercise in pandemiology?].

From a three-year old boy in Hong Kong who died in May 1997 with an extensive influenza pneumonia an influenza A virus has been isolated which was, first at the National Influenza Centre of the Netherlands, identified as belonging to subtype H5N1. Presumably the patient had acquired the infection directly from an outbreak of fowl plague among chickens. As far as is known this is the first case of the isolation of an influenza virus belonging to one of the subtypes H4-H15 from a human influenza patient. At the end of 1997 seventeen more cases of human A (H5N1) influenza have been detected in Hong Kong, including five fatal cases. Genetic analyses of seven of these virus isolates did not reveal the occurrence of reassortment with a human or porcine influenza virus, which could have rendered the virus potentially pandemic. Man-to-man transmission of the virus has not been demonstrated but cannot be excluded either. This event has shown that the WHO surveillance of influenza viruses, although perhaps not perfect, has functioned well.