Pathogenicity Of H5N1 Avian Influenza Virus For Pigeons

H5N1 avian influenza virus was isolated from a dead feral pigeon (Columba livia) during the investigation of outbreaks of H5N1 highly pathogenic avian influenza in waterfowl and wild birds in Hong Kong in late 2002. The public horror arose about whether pigeon can be an intermediate host in the transmission of H5N1 avian influenza.There have been existing the controversial opinions on the susceptibility of H5N1 virus of pigeons. It is still suspicious whether as resident birds, pigeons can play an important role in the transmission of avian influenza virus.To study the susceptibility, propagation, virulence and spread of H5N1 virus of domestic pigeons in China to intranasal (IN) inoculation with a H5N1 highly pathogenic avian influenza (HPAI) virus, we conducted experimental studies in pigeons using a panel of 10 strains of H5N1 HPAI vimses isolated from different species of diseased birds in geographically different areas of China mainland during 2002-2004. 16 pigeons in each group were infected nasally with 10⁶ EID₅₀ and clinical signs were recorded. The following virus titration of multiorgans and swabs and also pathological analysis at different time point were done.No mortality occurred within 21 days postinoculation (DPI) in 10 viruses infection experiment. But different from the former susceptibility research of H5N1 of pigeons, positive results can be acquired in the virus reisolation from swabs and organs of inoculated pigeons. Detection of viral antigen was confined to the central nervous system of these pigeons. But microscopic lesions were observed in multi-organs. In the cerebrum and to a minor extent in the brain stem a lymphohistiocytic meningoencephalitis presented with disseminated neuronal and glial cell necrosis, perivascular cuffing and glial nodules .Sequence analysis on the recovered DK/GDJD/23/04,RP/SXXY/47/04 and the receptor examination by staining revealed that it is possible for pigeon to be a intermediate host for the transmission of avian influenza.Additionally, the infectious status survey of H5N1 avian influenza virus of pigeons in Harbin City was also systematically done. According to the epidemiological data, avian influenza virus was not isolated from the targeted population in live birds markets, but the sampled 200 pigeons maintained a positive level of antibody against H9 avian influenza vims and Newcastle Disease.