Thai horse owners work to protect their horses from the biting insects that spread African horse sickness by installing screens on stables. | Photo: Courtesy Karen Wainwright

The death toll in the African Horse Sickness (AHS) outbreak in Thailand has nearly quadrupled in a little more than a week, reaching 154 deaths and a fatality rate of 94% in horses showing clinical signs, according to reports by the Thai government and the Thailand Equestrian Federation (TEF).

African horse sickness is a viral disease spread by various vectors including Culicoides–tiny, blood-sucking midges—and certain mosquitoes. While some healthy horses are testing positive in Thailand, those showing clinical signs have little chance of survival, an on-site veterinarian reported.

“The Pak Chong province has had a high number of deaths,” said Thapana Jarutummasiri, DVM, an equine veterinarian at TP Equine Ambulatory Services working throughout Thailand. That’s where most deaths have occurred, he added