Natural infection with highly pathogenic avian influenza virus H5N1 in domestic pigeons in Egypt.

In this study, an outbreak in domestic pigeons (1-18 months old) with 50% mortality was investigated. Pigeons exhibited nervous manifestations and greenish diarrhea. Necropsy of the naturally infected pigeons revealed congestion of the internal organs, particularly lungs and brain. A HPAIV subtype H5N1 designated A/Pigeon/Egypt/SHAH-5803/2011 was isolated from 40 days old pigeon. Sequencing of the hemagglutinin gene showed close relation to viruses in group 2.2.1/C. Intravenous inoculation of the isolate in chickens induced 100% mortality within 2 days postinoculation (dpi) and intravenous pathogenicity index was 2.7. Virus pathogenicity and transmissibility was determined experimentally in six-week-old domestic pigeons. Thirty percent of pigeons inoculated oronasally with 10(6) EID50 showed congested beak, conjunctivitis, depression and greenish diarrhea. A mortality rate of 10% was recorded preceded by severe neurologic signs consisting of torticollis, incoordination, tremors, and wing paralysis. Pathological examination revealed a friable brain tissue and congested meningeal blood vessels. The lungs appeared edematous and severely hemorrhagic. Subepicardial and petechial hemorrhages on the coronary fat were observed. Both infected and contact pigeons shed virus via the oropharynx and cloaca. To our knowledge, this is the first description and characterization of HPAIV in naturally infected pigeons in Egypt. Our findings reveal that pigeons can indeed be susceptible to H5N1...
Source: Avian Pathology - Category: Pathology Authors: Tags: Avian Pathol Source Type: research