Thailand has begun vaccinating about 4000 horses in a bid to contain the spread of the deadly African Horse Sickness, a disease that only affects horses and other equine animals.

More than 200 horses in seven provinces have died since the outbreak was first reported earlier this year, the first time the highly infectious AHS virus, transmitted by insects, has appeared in Southeast Asia.

Horse owners in northeastern Nakhon Ratchasima province have installed mosquito nets on stables and conduct regular temperature and health checks, while putting sick horses under quarantine.

The government has also banned the import and export of horses, zebras and related animals.

Veterinarians say if the disease cannot be contained by the mass vaccination, it could wipe out all 11,800 horses in Thailand, where they are kept mostly for racing and leisure riding for tourists and private owners.

"Without any prevention, 10 out of 10 horses will contract the virus... nine out of 10 sick horses will die from it," Aree Laikul, a veterinarian from Kasetsart University's faculty of Veterinary Medicine who is helping the vaccination drive, said on Monday.

There have been no reported cases of AHS in humans, and it is not related to the coronavirus pandemic.

AHS is endemic in the central tropical regions of Africa, from where it spreads regularly to Southern Africa and occasionally to North Africa, according to information from the World Organisation for Animal Health.