Pigeons are resistant to experimental infection with H7N9 avian influenza virus

Abstract

To determine the susceptibility of pigeons to the newly emerged avian influenza virus subtype H7N9, we experimentally infected three different types of pigeons (meat, town, and racing) with two different doses (2 × 10(4) or 2 × 10(5) EID50) of H7N9 avian influenza virus A/Chicken/China/2013 by either intranasal and intraocular inoculation (IN + IO) or intravenous injection (IV). In addition, the potential transmission of H7N9 to pigeons by direct close contact with experimentally infected pigeons and chickens was assessed. Results showed that none of the experimentally infected pigeons exhibited any clinical signs regardless of the infection route and dose. Of the 12 racing pigeons that were randomly selected and necropsied, none of them had any gross lesions. In agreement with this finding, virus was not isolated from all pigeons. No detectable H7-specific antibodies were found in any pigeon. In contrast, 11 of 31 chickens that were either directly infected with H7N9 by IN + IO inoculation or by contact with IN + IO-infected chickens had conjunctivitis. Virus was isolated from all 31 chickens and H7-specific antibodies were detected in these chickens. However, none of the IV-infected chickens or chickens in direct contact with IV-infected chickens had any clinical signs. No virus was isolated from these chickens and no H7-specific antibody was detected. Overall, we conclude that pigeons are less or not susceptible to the H7N9 virus at the doses used and are not likely to serve as a reservoir for the virus. However, the virus does cause conjunctivitis in chickens and can transmit to susceptible hosts by direct contact.

A Review of Avian Influenza A Virus Associations in Synanthropic Birds

“…The emergence of an avian H7N9 virus in China in 2013 resulted in evaluations of that virus in pigeons after the virus was isolated from both wild and domestic pigeons [ 60 ]. Pigeons experimentally inoculated with the emergent H7N9 virus showed high survival and minimal shedding of the virus [ 60 ], a finding similar to those found in two other studies [ 61 , 62 ]. Another experimental study of the emergent H7N9 virus simulated a live bird market where pigeons were exposed to infected animals in cages stacked above them; none of the pigeons became infected [ 63 ].…”

Avian influenza overview October 2016–August 2017

“…Other poultry species including ducks were successfully infected but the quantity of virus shed suggested no significant role in the spread of the disease to humans (Pantin-Jackwood et al, 2016). Field samples from pigeons were positively tested for A(H7N9), but experimental studies demonstrated the resistance of A(H7N9) and suggested that they had a minor role, if any, as a source of infection (Liu et al, 2015). Unfortunately, no published field or experimental data are available for the HPAI variant of A(H7N9) in China to date.…”

Experimental Infection of Local Domestic and Feral (Columba livia domestica) Pigeons with Local Isolate of H9N2 Influenza Virus: Virological and Histopathological Study.

“…The pathogenicity of AIVs in pigeons and the vulnerability of pigeons for various subtypes of avian influenza have investigated in some studies (Yamamoto et al 2011;Liu et al, 2015). Furthermore, the ability of pigeons in being carrier and reservoir for these viruses has been studied (Liu et al, 2007).…”