HORSE serum samples collected during the equine influenza outbreak may be subjected to extensive testing to find out if any animals are carrying the deadly Hendra virus following the death of a vet in Brisbane.

Ben Cunneen, 33, originally from Sydney, contracted the disease after treating horses at the Redlands Veterinary Clinic on Brisbane's bayside.

He was admitted to hospital five weeks ago and died at about 7pm on Wednesday, the third person in Queensland to die from the disease in 14 years.

Biosecurity Queensland's chief veterinary officer, Ron Glanville, said 5000 horses had been tested for Hendra virus since the first recorded deaths from the disease - that of trainer Vic Rail and 14 of his horses in 1994.

Though tests revealed no evidence of the virus in the general horse population, the virus that claimed the life of Dr Cunneen had mutated from the strain that killed Mr Rail, so a large number of horses may now have to be retested, Dr Glanville said.

"We are looking at [retesting] at the moment," Dr Glanville told reporters yesterday. "We have quite a significant serum there as a result of the equine influenza outbreak, and we'll be looking at testing a lot of samples."

A colleague of Dr Cunneen said the young vet's wife, Gillian, and his family kept vigil at the Princess Alexandria Hospital throughout his struggle with the disease.

"It is just devastating … he's been a valuable employee with us for quite a long time," the clinic's owner, David Lovell, told ABC radio yesterday.

A female veterinary nurse and colleague of Dr Cunneen who tested positive to the virus was released from the hospital on Tuesday and continues to be monitored by medical staff.

Dr Cunneen is believed to have grown up in Windsor and studied veterinary science at Sydney University between 1993 and 1997, colleagues said yesterday.

He took up his position as senior equine vet at the Queensland clinic in the late 1990s.

Hendra virus, named after a northside Brisbane suburb where it was discovered in 1994, is transmitted from bats to horses and then to humans, who develop flu-like symptoms, drowsiness and balance problems. A Mackay sugarcane farmer also died from the disease in 1995 after being involved in autopsies of horses.

With AAP