Trainers whose horses have raced at three recent Melbourne meetings have been advised to monitor their horses for clinical signs of Strangles after a clerk of the course's horse was confirmed with the infectious disease.

"Buddy", ridden by Shane Patterson, worked at Caulfield on July 15 and Flemington last Saturday.

Fellow clerk of the course horse "Brian", who is stabled with "Buddy", was on duty at Sandown on July 19.

Racing Victoria stewards were notified on Tuesday Buddy was showing clinical signs consistent with strangles with the diagnosis confirmed on Thursday.

The stewards have advised Patterson no horses are allowed to leave his stables which are located off-course in Flemington, until approval is granted by RV.

At this time, no restrictions or conditions have been placed on any other stable.

Strangles is an infectious bacterial condition that is transmitted via direct contact between individual horses and/or through indirect contact in several ways.

Strangles usually causes upper respiratory tract disease, but can also affect the lungs. It is highly contagious although rarely fatal.

Trainers have been asked to monitor all horses' temperatures in their stables twice a day which is vital as nasal shedding of the bacteria (which could spread the disease) typically occurs two to three days after the onset of fever.