A possible role for domestic dogs in the spread of African horse sickness virus

African horse sickness (AHS) is well known as one of the worst diseases affecting horses out there. Just like both Ebola in people and African swine fever virus in pigs, it causes severe haemorrhage and oedema in all organ systems. Affected horses essentially suffocate as their lungs fill with fluid. The disease is caused by infection with African horse sickness virus (AHSV), which is transmitted between equids by certain species of Culicoides biting midges and is not thought to be transmitted by other means. Although currently confined to sub-Saharan Africa, the virus has a history of spreading outside Africa, where it has caused devastating outbreaks in the Middle East, as well as in Spain and Portugal. Given the recent northward expansion of the main African vector of AHSV ( Culicoides imicola ) into the Mediterranean basin of Europe, the threat posed from AHSV in Europe is increasing. We have known for some time that domestic dogs are capable of being infected with AHSV and, apart from horses, the domestic dog is the only other species known to contract the severe form of the disease.1,2 Until recently, in all reported field outbreaks in dogs, there have been well-documented histories of eating of horse meat, so it was thought that the dogs were most likely being infected through the ingestion of infected horse meat, rather than through the bites of infected Culicoides midges. This made dogs a dead-end host of the virus, so it was generally believed that they did not play a significant role in the …