Three more horses have died from the Hendra virus on the New South Wales (NSW) north coast of Australia, the NSW Department of Primary Industries confirmed on Thursday. Two horses have died on a South Ballina property and one horse has died on a Mullumbimby property, Ian Roth, the Chief Veterinary Officer from the NSW Department of Primary Industries, said on Thursday. The Department of Primary Industries has quarantined both properties after the horses died. The latest cases follow the death of another horse at a different property near Ballina on Monday, where two other horses were also deemed to be at risk and continue to be monitored. Roth said seven properties in NSW had now been affected by the Hendra virus. \"It\'s critical horse owners maintain vigilance against this virus,\" he said in a statement. The most recent deaths bring the total number of horses killed by the virus in the state in the past eight weeks to nine. Another 10 Hendra-infected horses in Queensland have died or been put down since June 20, 2011. More than 60 people have been reportedly tested for Hendra across NSW and Queensland. The virus is spread from flying foxes to horses and, rarely, from horses to people. In one case in Queensland it was transmitted from horses to a dog. \"Four remaining horses on the South Ballina property and one horse at the Mullumbimby property are currently showing no signs of illness and will be monitored twice daily, Roth said on Thursday. \"People should keep horses away from fruiting and flowering trees that might attract fruit bats or other areas where bats are known to congregate\".