Characterizing Emerging Canine H3 Influenza Viruses

Area of Science:

• Virology
• Public Health
• Immunology

Background:

• Novel influenza A strains continually emerge from animal reservoirs, necessitating surveillance for potential human health risks.
• Canine influenza A viruses (CIVs) have caused widespread respiratory infections in dogs in the U.S. since 1999.
• The zoonotic potential of CIVs requires investigation due to their prevalence in a common companion animal.

Purpose of the Study:

• To assess the risk of canine influenza A viruses (CIVs) to human health.
• To evaluate the replication and transmission potential of CIVs in human cells and mammalian models.
• To identify potential therapeutic strategies, including antivirals and human monoclonal antibodies, against CIVs.

Main Methods:

• Replication assays using primary human cells.
• Transmission studies in mammalian models.
• Assessment of pre-existing human humoral immunity against CIVs.
• Evaluation of antiviral sensitivity and identification of cross-reactive human monoclonal antibodies (hmAbs).

Main Results:

• CIVs demonstrated replication in primary human cells and effective transmission in mammalian models.
• Individuals born after 1970 exhibited limited pre-existing humoral immunity to CIVs.
• CIVs were sensitive to existing antiviral medications.
• A panel of H3 cross-reactive human monoclonal antibodies (hmAbs) with potential prophylactic and therapeutic value was identified.
• Data suggest a low risk of CIVs to the human population.

Conclusions:

• Canine influenza A viruses (CIVs) show limited zoonotic risk to humans.
• Existing antivirals and identified human monoclonal antibodies offer potential treatment options.
• The Centers of Excellence for Influenza Research and Surveillance (CEIRS) network effectively collaborated to characterize emerging influenza viruses.