Prediction and Control of New Pandemic Influenza Viruses

从抗原性和遗传性两方面对中国南部地区鸭流感病毒分离株的H3血凝素(HA)进行了分析。这些结果为这些禽类作为A/Hong Kong/68(H3N2)毒株产生的“混合容器”将禽流感病毒传入猪的作用提供了分子证据。从不同宿主物种分离的H1-13甲型流感病毒株对猪的实验感染提供了以下信息；猪的上呼吸道细胞不仅对猪和人源H3流感病毒的HA敏感，而且对野鸭的HA也敏感；鸭和猪的流感病毒混合感染猪的上呼吸道产生了遗传重组体。猪对禽流感病毒的感染可能是HA型的。由此可见，猪只亦会感染H4-13甲型流感病毒，而H4-13甲型流感病毒只在禽类中被发现，而在感染禽流感病毒的猪只的血清中，并没有发现血凝抑制抗体。另一方面，ELISA在血清中清楚地显示出抗体反应，这些发现表明除H1-3以外的其他亚型流感病毒可能被引入猪体内，而HI试验的血清流行病学调查可能不能提供猪感染禽流感病毒的准确信息。

The H3 hemagglutinins (HA) of influenza virus isolates from domestic ducks in southern China were analyzed antigenically and genetically. The results provided molecular evidence of a role of these birds to introduce avian H3 influenza viruses to pigs as "mixing vessels" where A/Hong Kong/68 (H3N2) strain was produced.Experimental infection of pigs with H1-13 influenza A virus strains isolated from different host species provided the follwing informations ;The cells lining the upper respiratory tract of pig were susceptible not only to the HA of H3 influenza viruses of porcine and human origin but also to that of isolates from feral ducks.Genetic reassortants were produced in upper respiratory tract of pig mixedly infected with influenza viruses of duck and porcine origin.Pigs were susceptible to infection with avian influenza viruses eash know HA subtype. It is thus noted that pigs were also susceptible to H4-13 influenza A viruses which had been recognized only in avian species.Hemagglutination-inhibiting antibodies were not detected in the sera of the pigs infected with the avian influenza viruses. Antibody response was, on the other hand, clearly demonstrated in the sera by ELISA.These findings indicate that influenza viruses of other subtypes than H1-3 arepossible to be introduced into pigs and that seropidemiological survey by HI tests may not provide exact information of infection of pigs with avian influenza viruses.