The Australian Veterinary Association (AVA) is warning Australian horse owners to take precautions against mosquito-borne disease as veterinarians report a growing number of horses with unusual neurologic signs in New South Wales (NSW), Victoria, and South Australia.

"These cases are still under investigation; however, they may result from infection with a mosquito-borne virus in the Kunjin-West Nile group," said Christine Smith, DVM, Dipl. ACVS, of the Equine Veterinarians Australia.

"Clinical signs may include depression and mild colic," she continued. "These may also include the onset of neurologic signs including increased responsiveness to touch and sound, facial paralysis and difficulty masticating (chewing), hypermetria (incoordinated and exaggerated movement) in forelimbs and weakness in hindquarters, general ataxia (incoordination) and/or recumbency (inability to stand).

"Most of the horses involved appear to be recovering slowly, however there have also been reports of a few deaths," said Smith