An outbreak of equine influenza
(EI) in Australia
was confirmed by the New South Wales Department of Primary Industries
on 24 August 2007 in Sydney
. Also known as "horse flu" and "A1 influenza", the rapid outbreak was of the Influenza A virus
strain of subtype H3N8
. While the virus is highly contagious, it rarely kills adult horses but the performance of thoroughbred racing horses can be affected for several weeks. It can be fatal to young foals and debilitated horses.
Because of strict quarantine procedures to reduce the risk of exotic pests and diseases entering Australia, this was the first outbreak of equine influenza in Australia. Horses in Australia had not been exposed to the virus and, not being vaccinated, were fully susceptible.
A combination of control measures was successful in combating the outbreak. The last new infected property was identified on 22 December 2007. The zones which had been instituted to permit and restrict movements according to risk were progressively lifted from areas of New South Wales and Queensland.