Cattle were diagnosed in the Tea Gardens area last week and the virus, which is spread through mosquitos and biting insects, is likely to spread.

Vaccinations take 10 days to take effect and should be done before the virus is detected in the herd, Hunter Local Land Services district veterinarian Digby Rayward said.

“Those considering vaccinating stock should do so quickly as it is too late to vaccinate once the virus is in your herd,” he said.

“The virus is spread by biting insects and usually spreads rapidly under favourable conditions.”

The virus normally appears in mid to late summer.

Landholders should watch for potential cases and be prepared to nurse infected stock with anti-inflammatory medication to relieve fever and inflammation.

They will also need to provide food, water and shelter from the elements.

Dairy farmers often use the bovine ephemeral fever vaccine to protect their milking herd. Beef producers can also use this vaccine, particularly for high value animals like bulls, which can suffer temporary infertility as a result of infection.

The vaccine is only available from veterinarians.

Anyone planning to vaccinate should contact their vet to reserve enough vaccine as stock often runs low at this time of year.

Cattle which have previously had the disease normally develop long-term immunity.

The virus was less active last year so younger stock may have no immunity to the virus.

“Animals affected by three-day sickness experience a sudden onset of fever over 40 degrees, become lame and stiff in their joints and are often reluctant to move,” Mr Rayward said.

“They may drool, have watery eyes and a nasal discharge.

“Infected animals will often go down. Heavy animals, such as bulls and pregnant cows, appear to be affected the worst.”

Cattle are typically only unwell for several days, thus the name three-day sickness, but some cattle can take weeks to get up.

Farmers should make sure the affected animal does not become dehydrated.

“Farmers persisting with such animals need to be conscious of their comfort and welfare during this prolonged recovery period,” Mr Rayward said.

The virus can be diagnosed with a blood test in the early fever stage of the disease and on clinical signs. For more information visit www.hunter.lls.nsw.gov.au