AUTHOR=Liu Qingtao , Liu Yuzhuo , Yang Jing , Huang Xinmei , Han Kaikai , Zhao Dongmin , Bi Keran , Li Yin TITLE=Two Genetically Similar H9N2 Influenza A Viruses Show Different Pathogenicity in Mice JOURNAL=Frontiers in Microbiology VOLUME=7 YEAR=2016 URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2016.01737 DOI=10.3389/fmicb.2016.01737 ISSN=1664-302X ABSTRACT=
H9N2 Avian influenza virus has repeatedly infected humans and other mammals, which highlights the need to determine the pathogenicity and the corresponding mechanism of this virus for mammals. In this study, we found two H9N2 viruses with similar genetic background but with different pathogenicity in mice. The A/duck/Nanjing/06/2003 (NJ06) virus was highly pathogenic for mice, with a 50% mouse lethal dose (MLD50) of 102.83 50% egg infectious dose (EID50), whereas the A/duck/Nanjing/01/1999 (NJ01) virus was low pathogenic for mice, with a MLD50 of >106.81 EID50. Further studies showed that the NJ06 virus grew faster and reached significantly higher titers than NJ01