Duration and Frequency of Shedding of Influenza Virus H9N2 Subtype by Infected Birds based on an Experimental Study

The H9N2 avian influenza subtype is endemic in many parts of Iran and has the ability to transmit from bird to human. In the present study, the risk of this subtype for humans was assessed by determination of the viral titer and shedding time in bird.
The experiment was done on fifteen male budgerigars at 4 months of age. The birds were inoculated intranasally with allantoic fluid containing 106 EID50/ml of H9N2 virus. At days 1,3,5 and 7 post inoculation, viral presence and titer in the pharynx and cloacal were determined using TaqMan-real time-PCR.
The study showed that following infection of companion birds, viral shedding from pharyngeal and cloacal secretions can start one day after infection continued up to 7 days. In the early days, the viral titer in pharyngeal secretions is very high and reduces over time, while in the dropping of affected bird, it is low in the early days and increases, over time. Maximum viral shedding in the pharyngeal and fecal exertion was seen on days 3 and 5, respectively.
The results of the present study showed that the H9N2 subtype sheds from pharyngeal and cloacal secretions and releases in the environment. Due to the zoonotic nature of the influenza disease and the increasing tendency of people to keep birds, informing the public about the disease, duration of shedding, risk for human and strategies of disease prevention is necessary.