Avian Influenza Virus Infections in Humans: Avian influenza virus strains have only recently been identified as the cause of human disease. For most of these, the clinical manifestations in humans are mild. In 1996, an avian H7 virus was isolated from a woman with conjunctivitis (Kurtz Avian Influenza Virus Infections in Humans 165 1996). In 1999, a H9N2 strain was isolated in Hong Kong from two children with mild influenza symptoms (Peiris 1999, Horimoto 2001).