Mase M, Imada T, Sanada Y, Etoh M, Sanada N, Tsukamoto K, Kawaoka Y, Yamaguchi S
Department of Virology, National Institute of Animal Health, Tsukuba, Ibaraki 305-0856, Japan.
J Virol. 2001 Apr;75(7):3490-4. doi: 10.1128/JVI.75.7.3490-3494.2001.
In 1997 and 1998, H9N2 influenza A viruses were isolated from the respiratory organs of Indian ring-necked parakeets (Psittacula Krameri manillensis) that had been imported from Pakistan to Japan. The two isolates were closely related to each other (>99% as determined by nucleotide analysis of eight RNA segments), indicating that H9N2 viruses of the same lineage were maintained in these birds for at least 1 year. The hemagglutinins and neuraminidases of both isolates showed >97% nucleotide identity with those of H9N2 viruses isolated from humans in Hong Kong in 1999, while the six genes encoding internal proteins were >99% identical to the corresponding genes of H5N1 viruses recovered during the 1997 outbreak in Hong Kong. These results suggest that the H9N2 parakeet viruses originating in Pakistan share an immediate ancestor with the H9N2 human viruses. Thus, influenza A viruses with the potential to be transmitted directly to humans may be circulating in captive birds worldwide.
1997年和1998年，从从巴基斯坦进口到日本的印度环颈鹦鹉（Psittacula Krameri manillensis）的呼吸器官中分离出H9N2甲型流感病毒。这两个分离株彼此密切相关（通过对八个RNA片段的核苷酸分析确定，相似度>99%），表明同一谱系的H9N2病毒在这些鸟类中至少维持了1年。两个分离株的血凝素和神经氨酸酶与1999年在香港从人类分离出的H9N2病毒的血凝素和神经氨酸酶核苷酸同一性>97%，而编码内部蛋白的六个基因与1997年香港疫情期间分离出的H5N1病毒的相应基因同一性>99%。这些结果表明，源自巴基斯坦的H9N2鹦鹉病毒与H9N2人类病毒有直接的共同祖先。因此，具有直接传播给人类潜力的甲型流感病毒可能正在全球圈养鸟类中传播。
