New strategy accelerates horse flu eradication

New strategy accelerates horse flu eradication

No new cases of equine influenza in 2008 puts Australia on track to eradicate the disease by mid-March.

Australia’s Chief Veterinary Officer, Dr Andy Carroll said the national eradication program for equine influenza (EI) is making excellent progress.

“It is an extremely positive sign that the number of infected properties is decreasing so quickly,” Dr Carroll said. “More than ninety-seven per cent of previously infected properties are now cleared of the disease and it has been four weeks since the last reported case.”

Some weeks ago, NSW and Queensland eased movement restrictions in several zones.

“Zoning effectively contains disease and is a key element of the EI eradication program,” Dr Carroll said. “Zoning continues to provide a technically sound basis for determining conditions for the safe movement of horses around Australia.

“This success will increasingly allow some horses that are vaccinated or blood tested positive to EI, to participate in horse sales, other sporting events and to move more freely around Australia.”

The National Management Group has endorsed a strategy to accelerate the eradication program of EI from Australia.

“The strategy sets out the rationale, necessary actions, required resources and costs, and key outcomes for an accelerated zone progression strategy to achieve EI eradication from Australia,” Dr Carroll said. “It also builds on the excellent progress made to date and takes into account the surveillance requirements necessary for proving freedom from EI.”

The Consultative Committee on Emergency Animal Diseases agreed to reclassify green zones to white in Queensland and NSW, from 1 February 2008. Previous red zones in NSW at Dubbo, Wellington, Narrabri, Gunnedah, Parkes, Forbes, Walcha and part of the Grenfell district were also reclassified to amber.

Vaccinations continue in NSW and Queensland with more than 90 per cent of targeted horses having received their first vaccination and more than 80 per cent receiving their second vaccination.

Dr Carroll said that while the eradication program is making excellent progress, it is vital to maintain strict biosecurity and movement restriction arrangements must still be adhered to, if Australia is to be successful in eradicating the disease by the end of March.

“We are winning the battle against EI, but it only takes one person to do the wrong thing and we could face a major setback,” Dr Carroll said. “It is vital that anyone who suspects EI reports it immediately to 1800 234 002.”

Note to editors: a fuller description of the current response effort in NSW and Queensland follows.

Attachment A

Equine influenza

Summary of current situation and plans for New South Wales and Queensland

NEW SOUTH WALES

Equine influenza in New South Wales is now confined to below Picton (south west of Sydney) northwest to the Queensland border, with some outlying western pockets of infection.

The epidemic peaked in early October 2007 and declined steadily thereafter. In late September 2007, NSW was divided into green, amber, red and purple zones, which allowed risk-based movement and disease controls to be applied. Red and amber zones are progressively being cleared to green.

The most recent new infected premise (IP) displayed clinical signs on 9 December 2007 and was detected from samples submitted on 22 December. All IPs detected since late November were investigated and can be explained by local spread in known clusters of infection in the purple or red zones.

QUEENSLAND

Equine influenza is now confined to the current red zone in the south-east corner of Queensland, where about 70,000 horses reside.

The epidemic peaked in late October 2007 and declined steadily thereafter. The most recent new infected premise displayed clinical signs on 25 December 2007.

All IPs detected during December were investigated and can be explained by local spread in known clusters of infection either in the Caboolture area to the north of Brisbane or the Jimboomba – Cedar Grove area to the south. These areas are small acreage blocks with high horse densities. Disease control in this type of area is the primary concern because the close proximity of horses has made it difficult to stop local spread.

INFECTION ISSUES

While it is possible that low levels of infection remain in isolated pockets in the NSW purple zone and the QLD red zone, NSW DPI and QLD DPI&F are confident the epidemic is under control.

The key factors favouring eradication in New South Wales and Queensland are:

• no breakouts of infection in the original NSW green zone and only limited new foci in the original amber or red zones up to early October
• containment to Queensland’s south-east region
• a low number and density of susceptible horses (the majority of horses have recovered or are vaccinated)
• current climatic conditions (hot and humid) do not favour virus survival outside the horse.

Elements of the NSW and QLD programs that have led to this confidence include:

• Vaccination buffer zones in both states to guard against wider lateral spread of infection.
  
  
• Strategic vaccination of high risk groups of horses based on industry segments and strategic geographic areas. This has stopped widespread infection in segments such as racehorses and brood mare farms, as well as stopping the spread from small acreage areas. No infection has been detected on farms after 14 days following the first dose of vaccine.
  
  
• About 50,000 horses in New South Wales and 62,000 in Queensland have been vaccinated.
  
  
• Strict movement controls within and out of the red and amber zones and to zones of lower status. Movements have been controlled by permit on a risk assessment basis. Approved quarantine facilities have been set up to manage horse movement out of the red zone in Queensland. Less than 50 horses have moved to the Queensland green zone from the red zone.
  
  
• Movement controls have been actively enforced with signage and compliance monitoring. In New South Wales, over 1,000 compliance investigations have been completed with two successful prosecutions and four prosecutions still pending. In Queensland, about 1,800 compliance investigations have been completed with 16 prosecutions pending.
  
  
• Biosecurity protocols have been actively promoted at the property and industry levels within all sectors using a variety of extension methods.
  
  
• Community education and support for horse owners has been heavily resourced in both states using Industry Liaison Officers, community meetings, industry groups, web information and community engagement centres. The QLD DPI&F call centre has handled about 70,000 EI related calls.
  
  
• Compulsory registration of horse properties and extensive verification work to set up horse property locations.
  
  
• A multifaceted surveillance program based on:
  
  
  • reporting and investigating cases with suspect clinical signs and other factors – more than 20,000 investigations in NSW and more than 1,600 investigations in Queensland
    
  • epidemiological investigation of infection spread within cluster areas, as well as any ‘outliers’
    
  • feedback from farm visits by veterinarians and farriers
    
  • intensive telephone surveillance of horse properties. In Queensland, about 16,800 properties in the red zone and close to 12,000 in the amber zone have been directly contacted by telephone. Properties surrounding known areas of infection were targeted specifically.
    
  • precise tracking of infection through GIS systems and analysis using appropriate data layers
    
  • targeted testing of horses that attend races, events and sales.
  
  
• Resolution of previously identified IPs, SPs and DCPs according to national guidelines. There are now less than 50 IPs in NSW from a peak of 6,800 and less than 200 IPs in Queensland from a peak of more than 2,000.

WORK PLAN

It is now appropriate to commence intensive surveillance in both states for ‘proof of freedom’. This includes:

Amber to green (or white) zone

• Complete testing of randomly selected horse properties (400 in NSW and 180 in Qld) throughout the zone and current passive surveillance by mid February.
  

NSW purple to green zone

• Complete the resolution of all infected and suspect properties by end of February.
• Increase the emphasis on reporting suspect signs and intensive investigation.
• Active surveillance that includes:
  
  
  • random surveillance – complete testing of 2,000 properties in six divisions within the zone by early March
    
  • intensive surveillance in the most recent cluster areas of infection
    
  • ongoing targeted surveillance by testing horses at events and other horse gatherings
    
  • further PCR testing of about 2,500 horses at first and 12,000 at second round vaccination.

QLD red to green zone

• Complete the resolution of all infected and suspect properties by mid-February.
• Increase the emphasis on reporting suspect signs and intensive investigation.
• Active surveillance that includes:
  
  
  • random surveillance – complete testing of 900 properties within three major areas of the zone by early March
    
  • intensive surveillance in the most recent cluster areas of infection
    
  • ongoing targeted surveillance by vaccination teams at events, other horse gatherings and abattoirs.

The implications of detecting new infections in either state will be determined on a case by case basis in consultation with CCEAD. The response will be driven by the circumstances of each situation (eg location of infection, proximity to other horses, known source of infection etc).

Any case would be immediately quarantined and an intensive investigation initiated. Movements in the immediate vicinity would be restricted, again determined by the circumstances, but initially involving a 5-10 km zone around the infected premise. Any un-vaccinated horses within this zone would be vaccinated as a priority.

Depending on the scale of infection found, tighter movement restrictions could be introduced more broadly and/or the proof of freedom phase could be extended.

Media contact: Dr Andy Carroll - phone DAFF Media +61 2 6272 3232 | www.outbreak.gov.au