Host-Adaptive Signatures of H3N2 Influenza Virus in Canine.
Authors: Li Xueyun, Liu Jia, Qiu Zengzhao, Liao Qijun, Peng Yani, Chen Yongkun, Shu Yuelong
Journal: Frontiers in veterinary science
Summary
# Editorial Summary Understanding how influenza viruses adapt when jumping between species has become increasingly important for veterinary surveillance, particularly following the identification of H3N2 canine influenza viruses (CIVs) circulating in dog populations worldwide. Researchers analysed 54 genetic signatures associated with canine adaptation in H3N2 viruses, identifying specific amino acid positions—particularly within the polymerase complex that forms part of the viral ribonucleoprotein machinery—that distinguish canine-adapted strains from their avian and human counterparts with over 95% accuracy. Nine of these adaptive sites appear conserved across multiple host transitions (avian-to-human, avian-to-equine, and equine-to-canine), suggesting these particular mutations confer a general advantage for crossing mammalian species barriers, whilst notably, H3N2 CIVs retained few human-like residues, indicating relatively low zoonotic risk to people. The research demonstrates that lower mammals establish persistent influenza transmission chains more readily than higher mammals, implying that companion animals warrant enhanced virological monitoring to detect emerging variants before they stabilise in new host populations. For equine professionals, this work underscores the value of recognising H3N2 as a genuine cross-species threat and supports the case for robust infection control protocols when managing horses with respiratory disease in multi-species settings where canine contact occurs.
Read the full abstract on PubMed
Practical Takeaways
- •Enhanced surveillance for emerging adaptive mutations in companion animals is necessary to monitor influenza virus evolution and potential cross-species transmission risks
- •The shared adaptive signatures between equine and canine strains indicate that equine facilities should implement biosecurity measures to prevent potential virus spillover between species
- •Current H3N2 canine influenza strains pose low direct zoonotic risk to humans based on genetic analysis, but continued monitoring is warranted
Key Findings
- •54 canine-adaptive signatures identified in H3N2 CIVs, concentrated in polymerase protein interaction regions with >95% accuracy in host distinction
- •Nine adaptive signatures (PB2-82, PB1-361, PA-277, HA-81/111/172/196/222/489) shared between avian-human/equine and equine-canine comparisons, implicating them in canine adaptation
- •Lower mammals establish persistent IAV transmission more readily than higher mammals, with 25 common H3 adaptation signatures across avian-mammal comparisons
- •H3N2 CIVs contain few human-like residues, suggesting low zoonotic risk to humans