A vet who was exposed to Hendra virus at a central Queensland horse stud has tested positive to the potentially deadly illness.

The man was admitted to Rockhampton Base Hospital yesterday after showing symptoms.

He was transferred to Brisbane's Princess Alexandra Hospital overnight in a critical condition.

The vet had treated two horses with the virus that died at a Cawarral property on August 7 and 8.

Three other people were also exposed to the virus but Queensland's chief health officer, Jeannette Young, says there is no reason to suspect the trio have the virus.

"The other three, at this point, we don't believe have the infection. If any of them become unwell we've asked them to represent for testing," she said.

The owner of the stud, John Brady, said the situation was "devastating".

"He's (the vet) been admitted into the Princess Alexandra Hospital to be monitored," Mr Brady said.

"It's devastating for all of us. He's in a critical condition.

"I'm going to have a meeting with all of my staff to discuss their symptoms and whether they too should go to the PA."

Hendra virus is potentially deadly for infected people.

Brisbane vet Ben Cunneen died after contracting Hendra from a horse 12 months ago.

- ABC/AAP