Pathogenic influenza B virus in the ferret model establishes lower respiratory tract infection

Abstract

Influenza B viruses have become increasingly more prominent during influenza seasons. Influenza B infection is typically considered a mild disease and receives less attention than influenza A, but has been causing 20 to 50 % of the total influenza incidence in several regions around the world. Although there is increasing evidence of mid to lower respiratory tract diseases such as bronchitis and pneumonia in influenza B patients, little is known about the pathogenesis of recent influenza B viruses. Here we investigated the clinical and pathological profiles of infection with strains representing the two current co-circulating B lineages (B/Yamagata and B/Victoria) in the ferret model. Specifically, we studied two B/Victoria (B/Brisbane/60/2008 and B/Bolivia/1526/2010) and two B/Yamagata (B/Florida/04/2006 and B/Wisconsin/01/2010) strain infections in ferrets and observed strain-specific but not lineage-specific pathogenicity. We found B/Brisbane/60/2008 caused the most severe clinical illness and B/Brisbane/60/2008 and the B/Yamagata strains instigated pathology in the middle to lower respiratory tract. Importantly, B/Brisbane/60/2008 established efficient lower respiratory tract infection with high viral burden. Our phylogenetic analyses demonstrate profound reassortment among recent influenza B viruses, which indicates the genetic make-up of B/Brisbane/60/2008 differs from the other strains. This may explain the pathogenicity difference post-infection in ferrets.

Domestic Pigs Are Susceptible to Infection with Influenza B Viruses

“…Interestingly, in our animal infection experiment, B/Victoria lineage virus replicated and transmitted more efficiently than B/Yamagata lineage virus in pigs. This is also in agreement with recent findings in the ferret model that the Victoria lineage virus replicates more efficiently and is more pathogenic than the Yamagata lineage virus (13). It is unclear if more efficient viral replication in vivo correlates with higher antibody titers.…”

A Guide for the Use of the Ferret Model for Influenza Virus Infection

“…21 Unlike influenza A viruses, influenza B viruses have not been extensively studied in ferrets, but have been reported to cause mild to moderate disease. 22 Although influenza C viruses have been associated with human infection, 23 and influenza D viruses are associated with cattle and feral swine infection, 24 neither are frequently studied in mammalian models. Accordingly, most of the information presented herein pertains to the study of influenza A virus infection in ferrets.…”

Historical H1N1 Influenza Virus Imprinting Increases Vaccine Protection by Influencing the Activity and Sustained Production of Antibodies Elicited at Vaccination in Ferrets

“…Ferret were infected intranasally as previously done [29]. Briefly, ferrets were anesthetized and infected with seasonal viruses or pandemic viruses at 10 6 EID 50 .…”