Comparison of the virulence of three H3N2 canine influenza virus isolates from Korea and China in mouse and Guinea pig models

Abstract

BackgroundAvian-origin H3N2 canine influenza virus (CIV) has been the most common subtype in Korea and China since 2007. Here, we compared the pathogenicity and transmissibility of three H3N2 CIV strains [Chinese CIV (JS/10), Korean CIV (KR/07), and Korean recombinant CIV between the classic H3N2 CIV and the pandemic H1N1 virus (MV/12)] in BALB/c mouse and guinea pig models. The pandemic H1N1 (CA/09) strain served as the control.ResultsBALB/c mice infected with H1N1 had high mortality and obvious body weight loss, whereas no overt disease symptoms were observed in mice inoculated with H3N2 CIV strains. The viral titers were higher in the group MV/12 than those in groups JS/10 and KR/07, while the mice infected with JS/10 showed higher viral titers in all tissues (except for the lung) than the mice infected with KR/07. The data obtained in guinea pigs also demonstrated that group MV/12 presented the highest loads in most of the tissues, followed by group JS/10 and KR/07. Also, direct contact transmissions of all the three CIV strains could be observed in guinea pigs, and for the inoculated and the contact groups, the viral titer of group MV/12 and KR/07 was higher than that of group JS/10 in nasal swabs. These findings indicated that the matrix (M) gene obtained from the pandemic H1N1 may enhance viral replication of classic H3N2 CIV; JS/10 has stronger viral replication ability in tissues as compared to KR/07, whereas KR/07 infected guinea pigs have more viral shedding than JS/10 infected guinea pigs.ConclusionsThere exists a discrepancy in pathobiology among CIV isolates. Reverse genetics regarding the genomes of CIV isolates will be helpful to further explain the virus characteristics.

Morphological features and pathogenicity of mutated canine influenza viruses from China and South Korea

“…JS10 has naturally occurring two amino acid (2‐aa) insertions at the distal end of the neuraminidase (NA) stalk. Consistent with previous studies, the long stalk strain showed more severe pathologic damage in mice and guinea pigs (Xie et al, ). However, no significant difference in cellular uptake between KR07 and JS10 was observed in this study.…”

“…For the attachment and endocytosis of influenza virus, HA initiates the recognition and attachment of receptors on target cells, albeit NA plays the role of sialidase, facilitating release of the virus during budding from the host cell, which rarely affects cellular uptake. Therefore, it may reasonably be speculated that the 2-aa insertion of NA may not contribute to the cellular uptake of canine influenza viruses, even though the long stalk strain, JS10, has higher infectivity and wider organ tropism than KR07 (Xie et al, 2018).…”

“…The presence of 2‐aa insertions in NA was observed in many isolates from different provinces of China, such as Zhejiang (Teng et al, ), Beijing and Liaoning (Sun et al, ). The isolate showed enhanced viral replication in mice and guinea pigs (Xie et al, ), albeit it was low in chickens, indicating inappropriateness for replication in poultry (Lin et al, ).…”

Fumonisin B1 aggravates inflammatory injury via mTORC1/pyroptosis, while promotes viral replication via mTORC1/apoptosis in Canine influenza virus-infected mice and A549 cells

“…al and Dan Zhao et. al, the infected mice showed declined clinical symptoms and decreased viral load since day 5 or 7 post infection, and in our in vivo experiments, the mice were terminated at the day 5 post infection which stands for the late stage of infection (Lin et al, 2016;Xie et al, 2018). Interestingly, mycotoxins exposure also can induce pyroptosis (Li et al, 2021).…”

Role of CARD Region of MDA5 Gene in Canine Influenza Virus Infection

“…CIV was first reported in 2004, and molecular and antigenic analyses found that its genome is closely related to the equine influenza genome [11]. Although dogs are the natural host of CIV, researchers have successfully infected pigs and mice with the CIV [12,13], and researchers also isolated equine flu from pig and donkey in China [14,15], which spread across the host due to the high variability of influenza viruses. Therefore, further studies of canine innate immune response are important to control the spread of the virus.…”