January 20, 2008

It is unlikely that further infections of equine flu will be detected in New South Wales, a recent report on eradication reveals.

Even if one or more cases did eventuate in the once highly infected purple zone, is it unlikely to stop the great majority of the zone being changed to green status in mid-March, as planned.

The document, from the state's Department of Primary Industries, outlines the strategies that will see what was once the worst affected part of the state move to freedom from the disease.

"It is unlikely that further infections of EI will be detected in the purple zone or elsewhere in NSW," the department said.

The most recent property to become infected in NSW was probably in early December, and the last positive laboratory test was on December 22, although that case was understood to be three weeks old.

"We believe that there is now little or no active infection in NSW. But we need to be sure before we relax control measures."

The department said the purple zone and its surrounding red zone will be treated as a single unit for the purposes of progressing it to green status, with new requirements for the movements of horses being one of the first steps. As well as the current need for Travelling Horse Statements, from February 4 movements will be limited to vaccinated or recovered horses only.

That, together with event registration, will allow rapid tracing in case of a fresh outbreak.

"Events represent a particular risk in that they concentrate horses from a variety of locations, and the horses disperse widely after the event.

"The limitation of movement to vaccinated or recovered horses will limit the exposure of 'susceptible' horses to potential contact with the EI virus.

"As far as we know, there should be few horses in the purple zone that are not either vaccinated or recovered. This restriction on the movement of susceptible horses is likely to be lifted as soon as the area is rezoned, but it may remain as a recommendation for event organisers."

The department outlined the requirements for the purple zone to move green by mid-March:

If a case or cases did occur, the properties in question would be quarantined and a 14-day lockdown would be imposed on a 10km radius.

"There will be a visible security presence on the infected property and the surrounding area."

Susceptible horses within the 10km buffer area will be vaccinated and a thorough tracing investigation launched to pinpoint the source of the infection and any possible avenues of spread.

"Any new quarantine area is effectively a red zone and will not be progressed with the rest of the purple zone. This means that one or two isolated cases will not delay the progression of the rest of the purple zone."

Remaining isolated red zones in the state are expected to be moved to amber before the end of January.

"Unless there are further cases in these areas, we would expect them to progress to green a month after the change to amber."

Remaining amber zones are expected to be progressed to green by mid-February. The only exception will be a fringe around the remaining red and purple zones.

The green zone, which already covers a great majority of the state, is expected to expand significantly in coming weeks.

It is unlikely that vaccination will be in general use after EI is eradicated from Australia.