The large populations of flying foxes on the north coast has prompted a warning from the Australian Veterinary Association for horse owners to be on the watch for Hendra virus.
The large colonies are active and in search of food, increasing the risk of the virus, which is spread to horses by the bats.
Horse owners should watch for symptoms which include respiratory distress, frothy nasal discharge, high temperature and a rapid heart rate.
Since 1994 Hendra virus has been confirmed in 40 horses and seven people.
