http://jvi.asm.org/cgi/content/abstract/JVI.00534-09v1
Reassortment between avian H5N1 and human H3N2 influenza viruses in ferrets: a public health risk assessment
<nobr>Sara Jackson,</nobr> <nobr>Neal Van Hoeven,</nobr> <nobr>Li-Mei Chen,</nobr> <nobr>Taronna R. Maines,</nobr> <nobr>Nancy J. Cox,</nobr> <nobr>Jacqueline M. Katz,</nobr> and <nobr>Ruben O. Donis<sup>*</sup></nobr> Influenza Divison, Centers for Disease Control and Prevention, Atlanta, GA
This study investigated whether transmissible H5 subtype human-avian<sup> </sup>reassortant viruses could be generated in vivo. To this end,<sup> </sup>ferrets were co-infected with recent avian H5N1 (A/Thailand/16/04)<sup> </sup>and human H3N2 (A/Wyoming/3/03) viruses. Genotype analyses of<sup> </sup>plaque-purified viruses from nasal secretions of co-infected<sup> </sup>ferrets revealed that approximately 9% of recovered viruses<sup> </sup>contained genes from both progenitor viruses. H5 and H3 subtype<sup> </sup>viruses, including reassortants, were found in airways extending<sup> </sup>towards and in the upper respiratory tract of ferrets. However,<sup> </sup>only parental H5N1 genotype viruses were found in lung tissue.<sup> </sup>Approximately 34% of the recovered reassortant viruses possessed<sup> </sup>the H5 HA gene, with 5 unique H5 subtypes recovered. These H5<sup> </sup>reassortants were selected for further studies to examine their<sup> </sup>growth and transmissibility characteristics. Five H5 viruses<sup> </sup>with representative reassortant genotypes showed reduced titers<sup> </sup>in nasal secretions of infected ferrets as compared to the parental<sup> </sup>H5N1 virus. No transmission by direct contact between infected<sup> </sup>and naïve ferrets was observed. These studies indicate<sup> </sup>that reassortment between H5N1 avian influenza and H3N2 human<sup> </sup>viruses occurred readily in vivo and furthermore that reassortment<sup> </sup>between these two viral subtypes is likely to occur in ferret<sup> </sup>upper airways. Given the relatively high incidence of reassortant<sup> </sup>viruses from tissues of the ferret upper airway, it is reasonable<sup> </sup>to conclude that continued exposure of humans and animals to<sup> </sup>H5N1 alongside seasonal influenza viruses increases the risk<sup> </sup>of generating H5 subtype reassortant viruses that may be shed<sup> </sup>from upper airway secretions.
Reassortment between avian H5N1 and human H3N2 influenza viruses in ferrets: a public health risk assessment
<nobr>Sara Jackson,</nobr> <nobr>Neal Van Hoeven,</nobr> <nobr>Li-Mei Chen,</nobr> <nobr>Taronna R. Maines,</nobr> <nobr>Nancy J. Cox,</nobr> <nobr>Jacqueline M. Katz,</nobr> and <nobr>Ruben O. Donis<sup>*</sup></nobr> Influenza Divison, Centers for Disease Control and Prevention, Atlanta, GA
This study investigated whether transmissible H5 subtype human-avian<sup> </sup>reassortant viruses could be generated in vivo. To this end,<sup> </sup>ferrets were co-infected with recent avian H5N1 (A/Thailand/16/04)<sup> </sup>and human H3N2 (A/Wyoming/3/03) viruses. Genotype analyses of<sup> </sup>plaque-purified viruses from nasal secretions of co-infected<sup> </sup>ferrets revealed that approximately 9% of recovered viruses<sup> </sup>contained genes from both progenitor viruses. H5 and H3 subtype<sup> </sup>viruses, including reassortants, were found in airways extending<sup> </sup>towards and in the upper respiratory tract of ferrets. However,<sup> </sup>only parental H5N1 genotype viruses were found in lung tissue.<sup> </sup>Approximately 34% of the recovered reassortant viruses possessed<sup> </sup>the H5 HA gene, with 5 unique H5 subtypes recovered. These H5<sup> </sup>reassortants were selected for further studies to examine their<sup> </sup>growth and transmissibility characteristics. Five H5 viruses<sup> </sup>with representative reassortant genotypes showed reduced titers<sup> </sup>in nasal secretions of infected ferrets as compared to the parental<sup> </sup>H5N1 virus. No transmission by direct contact between infected<sup> </sup>and naïve ferrets was observed. These studies indicate<sup> </sup>that reassortment between H5N1 avian influenza and H3N2 human<sup> </sup>viruses occurred readily in vivo and furthermore that reassortment<sup> </sup>between these two viral subtypes is likely to occur in ferret<sup> </sup>upper airways. Given the relatively high incidence of reassortant<sup> </sup>viruses from tissues of the ferret upper airway, it is reasonable<sup> </sup>to conclude that continued exposure of humans and animals to<sup> </sup>H5N1 alongside seasonal influenza viruses increases the risk<sup> </sup>of generating H5 subtype reassortant viruses that may be shed<sup> </sup>from upper airway secretions.
