He is in an induced coma in hospital, having been transferred last night from Rockhampton Hospital to Princess Alexandra Hospital in Brisbane.
He is the seventh known person to have contracted the virus.
The vet, from Rockhampton, was was one of four people considered at risk of infection who spent five days in hospital receiving an experimental anti-viral treatment with a drug called ribavirin, normally used in the treatment of hepatitis.
He underwent the treatment in the hope it would reduce the chance of infection developing.
He is reported to be in a critical but stable condition.
He contracted the virus, which is carried by native fruit bats called flying foxes, in treating a horse at the J4S Equine Nursery at Cawarall, where two horses are confirmed to have died from the virus.
Three of the six people who contracted the virus before this latest case died, including Brisbane vet Ben Cunneen, who died a year ago after an outbreak at a Redlands veterinary clinic.
The Australian Horse Industry Council said the case emphasises again the danger of Hendra virus.
"Everybody who has horses that might come into contact with areas frequented by flying foxes all over Australia needs to take appropriate precautions to prevent infection of humans and other horses.
"All flying fox populations are potentially infected with Hendra virus. Horses are an amplifying host."
"Though Hendra virus infection outside flying foxes is unusual, it appears to be becoming more frequent in recent years.
"No matter where you are in Australia it is imperative that you keep your horses away from fruit-eating bats."