Experimental transmission in guinea pigs of H9N2 avian influenza viruses from indoor air of chicken houses

► We studied the transmission of H9N2 AIV among mammals and investigated virus aerosol occurrence. ► No infection was detected in aerosol contact animals while AIV aerosols were detected. ► We quantified the aerosol infecting dose of H9N2 AIV to mammals. ► H9N2 AIV aerosols could infect guinea pigs at certain concentrations in experimental condition.