2007 Australian Equine influenza outbreak

An outbreak of equine influenza (EI) in Australia was confirmed by the Department of Primary Industries (New South Wales) 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. Following the provisional declaration of EI-free status for New South Wales and Queensland, ongoing surveillance and tracking measures are required until the international community recognises that the disease has been eradicated from Australia.

Four Japanese racing stallions had arrived at Eastern Creek Quarantine Station earlier in August 2007, soon after an outbreak of EI in Japan. By Tuesday 21 August, several horses at Eastern Creek showed symptoms of a viral infection and subsequently tested positive for equine influenza. On the same day, several recreational horses at Centennial Parklands Equestrian Centre also displayed symptoms of infection. There was no direct contact between horses at Eastern Creek and horses at Centennial Park and investigations are underway.

The first case of EI in Australia was confirmed in a stallion at Eastern Creek on 24 August. The positive test resulted in the lockdown of approximately 60 horses at the Eastern Creek and Spotswood quarantine stations (in Sydney and Melbourne respectively). 16 horses at Eastern Creek and at Centennial Parklands tested positive for EI virus while another six exhibited symptoms. By the next day, there were over 80 suspected cases. All horses were isolated and a 72-hour national standstill on the movement of horses was declared.

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