Natural infection with highly pathogenic avian influenza virus H5N1 in domestic pigeons (Columba livia) in Egypt

Figures & data

Figure 1. Phylogenetic relationship of pigeon AIV, Egypt 2011 to other AIV H5N1 sequences available in GenBank. The tree was constructed on the basis of the 1594-nucleotide sequence of the HA gene using the neighbour-joining method and the Kimura two-parameter model in MEGA5 (www.megasoftware.net). Bootstrap values of 1000 resamplings as a percentage (>70%) are indicated at key nodes. The virus isolated in this study is marked with a solid square.

Figure 2. An experimentally infected pigeon at 5 d.p.i. 2a: Severe neurologic signs consisting of torticollis and wing paralysis. 2b: Brain showing severely congested meningeal blood vessels. 2c: Lungs showing oedema and haemorrhage. 2d: Pulmonary haemorrhage represented by occlusion of the alveolar spaces with erythrocytes. Haematoxylin and eosin, bar: 50 µm. 2e: Brain showing vacuolation, spongiosis, degenerated neurons (arrowheads), microglial cell infiltrations (arrows) and perivascular lymphocytic cuffing. Haematoxylin and eosin, bar: 50 µm. 2f: Immunostaining revealed sporadic moderate positive staining of the pneumocytes (asterisk), interstitial tissue and few intravascular mononuclear cells of the lungs (arrows). Immunohistochemistry, bar: 50 µm.

Figure 3. Virus titres in oropharyngeal and cloacal swabs collected from infected and contact pigeons at 3, 5 and 7 d.p.i. The mean value of virus titre (log 10 EID₅₀/ml) in swabs collected from three birds ± standard error.