Western
Meeting of Poultry
Clinicians and Pathologists
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Clinicians and Pathologists
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Avian Influenza in Australia C.
Riddell University of Saskatchewan
Outbreaks of virulent avian influenza occurred in domestic poultry in 1976 (2), 1985 (1) and 1992 within the central part of the State of Victoria. All three outbreaks were circumscribed with little or no spread beyond the original infected premises. All outbreaks were controlled by slaughter and eradication of affected flocks. Mortality reached 25% in one shed in 1976, 85% in one shed in 1985 and had exceeded 1% per day in one shed prior to slaughter of the affected birds in the most recent outbreak. Clinical signs in all outbreaks included facial swelling and swollen wattles due to subcutaneous edema. In all outbreaks there was association with wild birds, in particular waterfowl and in at least the last two outbreaks there were dugouts adjacent to the barns. In the 1975 and 1992 outbreaks evidence of infection with avian influenza virus without clinical disease was found in domestic duck farms adjacent to the chicken farms in which clinical disease occurred. The viruses in 1976 and 1985 were subtypes H7N7 and the virus in 1992 were subtype H7N3. The viruses were classified as virulent on the basis of laboratory tests. No source for the virus was definitely identified in any of the outbreaks. Evidence of influenza infection has been documented in wild birds in Australia and wild birds are considered the most probable source (3).
References Cross, G.M. The status of avian influenza in poultry in Australia. Proc. 2nd Int. Symp. Avian Influenza, Athens, Georgia. Pp 96 –103. 1986 Turner, A.J. The isolation of fowl plague virus in Victoris. Aust. Vet. J. 52:384. 1976. Westbury, H.A. Avian influenza. Aust. Vet. J. 66:427 – 428. 1989.
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