The man was among a number of people tested for the rare but deadly virus after several horses contracted the disease at a veterinary clinic in Redlands.

Clinic owner David Lovell said his employee had spent a night in hospital but had been discharged on Tuesday afternoon and was back home.

"He's in good spirits but is very concerned I would have to say, as we all are," Dr Lovell said.

The practice, which has about 40 horses on site at any one time, is in lock down while the Queensland Department of Primary Industries and Fisheries continues testing horses.

A DPI&F spokesperson said the latest round of tests were negative for the virus and no further symptoms had been detected.

Hendra is a rare virus that affects horses and can be transmitted to humans.

Biosecurity Queensland's chief vet Ron Glanville said some cases were expected now and then.

"Fortunately, Hendra virus does not spread like equine influenza, and is very difficult to catch," Dr Glanville said.

There have been no recorded cases of the virus being spread between humans.

Those who contracted Hendra in the past contracted the disease through close contact with affected horses.

One thoroughbred racehorse died from the virus and a second horse had to be put down at the Redlands Veterinary Clinic last week, while a third horse died on the weekend at Cannonvale in north Queensland.

It was the worst outbreak of the disease since it killed trainer Vic Rail and 14 horses in 1994.

Dr Lovelle said the practice's 30-odd full and part-time staff were all well but on a watching brief for symptoms.

"There's not a lot anyone can really do," he said.

"We've got to have complete faith in Queensland Health that they've assessed this person and gone to great lengths to work out a risk analysis.

"All of us here have taken reasonable satisfaction from the fact (Queensland Health) has decided that a) this person is at low enough risk to send home and b) the risk of that person spreading that disease to someone else in not high enough to warrant isolation or anything like that."