LAUSR

Highly pathogenic avian influenza viruses (HPAIVs) can cause serious damage to wild birds and poultry. In this study, HPAIVs were administered via intranasal instillation to juvenile and adult domestic ducks, consisting of inoculation and contact groups, for comparative contagiousness. Oropharyngeal (OP) and cloacal (CL) swab analysis showed the overall virus shedding to be higher in OP than in CL. In addition, OP virus titer was higher in adults than in juveniles in the contact group. Our results indicate that adult susceptibility to AIV infection was greater than juvenile susceptibility, in case of samples from inoculated OP swab 2 days past inoculation (dpi) and contact OP swab 7 dpi. AIV distribution in the pancreas in juveniles was higher than that in adults; however, the virus was not detected in the trachea of either adults or juveniles. In conclusion, the results of this study suggest that differences in infectivity and prevalence of viruses in adults and juveniles may be influenced by the species of birds and neuraminidase enzymatic activity of the virus.