Hendra virus caused disease in horses in Australia, and the human infections there were due to direct exposure to tissues and secretions from infected horses. Nipah virus caused a relatively mild disease in pigs in Malaysia and Singapore. Nipah virus was transmitted to humans, cats, and dogs through close contact with infected pigs.
In Australia humans became ill after exposure to body fluids and excretions of horses infected with Hendra virus. In Malaysia and Singapore, humans were infected with Nipah virus through close contact with infected pigs.