The first bird-to-human transmission of A/H5N1 virus was found during the influenza outbreak in Hong Kong in 1997. Eighteen people showed acute respiratory distress syndrome, and six of them died.
In 1999 and 2003 respectively, two girls and one boy suffered from A/H9N2 low pathogenic avian influenza with slight symptoms. The Netherlands reported outbreaks of influenza A (H7N7) in 2003. Eighty-nine people were confirmed to have H7N7 influenza virus infection, and one veterinarian among them died. The main symptom was conjunctivitis and no obvious pneumonic and respiratory syndromes were found. In February 2003, H5N1-infected cases occurred among members of a Hong Kong family (father and son) that had returned from Fujian, China. The son recovered, while the father died. In 2004, two H7N3-infected cases with symptoms of pneumonia and conjunctivitis were reported in Canada.
Human-infected cases were reported during the large-scale outbreak of H5N1 in Southeast Asia. From 2003 to September 15th, 2005, human-infected cases of A/H5N1 had been found in Thailand, Vietnam, Indonesia, and Cambodia. 114 people in total were infected, and 59 of them died, the mortality rate of which was approximately 50%. Currently, the mortality rate has decreased to 30% or so for the experts have learned the best timing for medication.