Transmission of low-pathogenicity avian influenza virus of subtype H6N2 from chickens to Pekin ducks and Japanese quail (Coturnix coturnix japonica)

In this experiment we evaluated the transmission characteristics of a chicken-adapted low-pathogenicity avian influenza virus (LPAIV) of subtype H6N2, from infected chickens to Japanese quail and Pekin ducks, which are commonly sold in live bird markets located in Southern California. The layout of the cages and bird-handling practices were similar to those found in Southern California live bird markets. Five out of 20 chickens were inoculated with LPAIV H6N2, and placed in direct contact with five chickens and in indirect contact with 10 chickens, 10 Japanese quail and 10 Pekin ducks. Transmission of LPAIV was followed in each bird daily for 15 days post inoculation by real-time reverse transcriptase-polymerase chain reaction testing of oropharyngeal and cloacal swab samples. This strain of H6N2 LPAIV, isolated from commercial poultry in California, was transmitted to chickens, quail, and ducks from chickens. An antibody response was detected in ducks by haemagglutination inhibition tests, but avian influenza virus was only detected by reverse transcriptase-polymerase chain reaction in one duck. Avian influenza virus was detected in quail (5 and 7 days post inoculation) before chickens (8 and 9 days post inoculation), all of which were in indirect contact with infected chickens; however, this difference was not statistically significant.