Heterogeneous pathological outcomes after experimental pH1N1 influenza infection in ferrets correlate with viral replication and host immune responses in the lung

Vidaña, Beatriz; Martínez, Jorge; Martínez-Orellana, Pamela; García Migura, Lourdes; Montoya, María; Martorell, Jaime; Majó, Natàlia

The striking heterogeneity of the clinicopathological outcomes observed after pH1N1 infection in humans lead to numerous studies initially focused on the impact of viral evolution and mutation on the virulence of the infection. Virulence markers have been mapped to the polymerase genes (PB1, PB2 and PA), neuraminidases (NAs), and the non-structural proteins (NS1s) of the highly pathogenic avian influenza viruses and the 1918 pandemic H1N1 strains [8] . Recently, it has also been suggested that genetic polymorphisms that affect the polymerase complex and the hemagglutinin (HA) subunit may contribute to the pathogenicity of certain pH1N1 strains by conferring on them the ability to produce higher viral titres or the ability to replicate over a prolonged period of time [9, 10] . The viral strains used in this work have been sequenced, and several mutations have been found in each of the viral strains [11] . However, the importance of these mutations in the pathogenicity of pH1N1 still needs to be clarified [11] .