During the first documented outbreak of human infections with H5N1, which occurred in Hong Kong in 1997, the 18 human cases coincided with an outbreak of highly pathogenic avian <e1>influenza</e1>, caused by a virtually identical <e2>virus</e2>, in poultry farms and live markets.
During the first documented
During the first documented outbreak of human infections with H5N1, which occurred in Hong Kong in 1997, the 18 human cases coincided with an outbreak of highly pathogenic avian influenza, caused by a virtually identical virus, in poultry farms and live markets.
<triplet> influenza <subject> virus <object> Cause-Effect(e2,e1)