ERADICATION OF EQUINE INFLUENZA

Rod Hoare from Industry Liaison summarises the campaign towards eradication so far.

“From Day 1 NSW DPI and other authorities have been working towards eradication of EI. How could Australia do this when Europe and America have not been able to eradicate it? South Africa and India have eradicated the disease: what are our chances?

NSW DPI and their many collaborators had some initial problems:

• The initial spread of infection prior to standstill was very widespread and into areas of high horse density.

• No vaccine supplies were on hand, no approvals were available, and vaccines would be a month coming.

• We did not know how the disease would spread under Australian conditions.

• The disease came at the worst time of the year – just before breeding season, just before foaling, in cool weather assisting survival of the virus. Spread from property to property occurred in the cool morning mists up to about 3 km.

NSW DPI and collaborators also had many advantages:

• NSW DPI staff and supporting agencies such as the Rural Fire Service are well trained in emergency response and did respond quickly.

• There was an AUSVETPLAN for EI.

• An excellent test (PCR test for presence of virus) was available, and a capacity to test up to 1000 samples overnight.

• The new generation of vaccines produces effective immunity against the strain in Australia after the first injection.

What progress has been made?
• The geographic area of Australia affected by equine influenza has not changed much in the past 6 weeks.

• There have been three new groups of infection in the green zone but these have now been contained with vaccination buffers.

• Now that adequate vaccine supplies are available, it is possible to respond more quickly and effectively to put out the spot fire situations.

• Vaccine supplies are still limited. Sending vaccine to uninfected states is like sending water tankers away from the fire front – highest priority for vaccine is where the disease is likely to occur.

• The daily number of new infected properties is much lower than it was mid September.

• The majority of infections are now occurring in previously infected areas and within vaccination buffers.

• A small proportion of Australia's horses have been exposed to EI virus - less than 10% of the total horse population.

• More horses are becoming immune to EI daily after recovering from EI infection or to the effects of vaccination.

• The first round of EI vaccinations in the buffer zones in NSW is more than 70% complete. The boundaries of some of the red and amber interfaces in NSW are to be replaced by amber and green zones respectively. The plan is to have all high risk horses in the NSW purple zone immune to EI due to infection or vaccination by 30 November 2007.

• Scenario analysis indicates that the outbreak is running below the mid-range prediction curve, and well below the worst case curve.

• The best guess prediction is that EI will be eradicated by 30 June 2008. This will depend on compliance with personal biosecurity.

The conclusion is that eradication is well on track and remains the number one priority.”