The Perak State Veterinary Services Department (VSD) issued the quarantine order after one of the horses at the farm died from the Strangles disease, a common infectious disease of horses.

Samples taken from a deceased 14-year-old mare, which had been a resident at the farm since 1998, showed that it suffered from Strangles, which is caused by the Streptococcus Equi bacteria.

State veterinary health officer Dr Wan Mohd Kamil Wan Nik said the presence of the disease was characterised by inflammation of the nasal mucous membrane and abscesses under the jaw and around the throat.

"This causes strangling or choking sensation, thus the term Strangles," he told the press when asked about the quarantine order issued upon the NSF.

He said with the quarantine in place, visitors were barred from entering the area and workers working closely with the horses were required to be disinfected everytime they leave the paddocks.

The disease did not affect humans, added Dr Wan Mohd Kamil.

The bacteria spreads primarily by droplet inhalation, although contamination of food and water with the discharges from an infected horse is Dr Wan Mohd Kamil said the VSD had started collecting mucous and blood samples from each of the 169 horses at the farm since June 6 to verify the extent of the infection.

"The quarantine will be lifted once the results of the samples collected over three consecutive weeks show negative results," he said.

He added that the NSF was giving full cooperation to the VSD to enable the quarantine order, if all results are negative, to be lifted by August.