Highly pathogenic avian influenza (H7N1) in ostriches (Struthio camelus)

The clinical, virological and pathological findings observed in a natural o utbreak of highly pathogenic avian influenza in intensively farmed ostriche s (Struthio camelus) are reported. Clinical signs characterized by anorexia , depression, nervous and enteric signs were observed in young birds, which resulted in death of 30% of the affected birds. Virus isolation performed in accordance with the guidelines listed in European Union Directive 92/40/ EEC yielded an influenza A virus of the H7N1 subtype with a deduced cleavag e site motif containing multiple basic amino acids, typical of highly patho genic viruses. Gross lesions, mainly haemorrhagic enteritis and liver degen eration and necrosis, were confirmed by histopathology and immunohistochemi stry, resulting in the detection of necrotic lesions and influenza A nucleo protein in selected organs. The findings reported indicate that ostriches a re susceptible to highly pathogenic avian influenza.