Sequential Transmission of Influenza Viruses in Ferrets Does Not Enhance Infectivity and Does Not Predict Transmissibility in Humans
Troy C. Sutton, Elaine W. Lamirande, Devanshi R. Patel, Katherine Johnson, Rita Czakó, Elodie Ghedin, Raphael Tze Chuen Lee, Sebastian Maurer‐Stroh, Kanta Subbarao
Abstract
Airborne transmission in ferrets is used to gauge the pandemic potential of emerging influenza viruses; however, some emerging influenza viruses that transmit between ferrets do not spread between humans. Therefore, we evaluated sequential rounds of airborne transmission in ferrets as a strategy to enhance the predictive accuracy of the ferret model. Human influenza viruses transmitted efficiently (>83%) over two rounds of airborne transmission, demonstrating that, like humans, ferrets infected by the respiratory route can propagate the infection onward through the air. However, emerging avian influenza viruses with associated host-adaptive mutations also transmitted through sequential transmission. Thus, airborne transmission in ferrets is necessary but not sufficient to infer transmissibility in humans, and sequential transmission did not enhance pandemic risk assessment.