African Horse Sickness (AHS) is a highly infectious but non-contagious viral disease affecting horses, mules, and donkeys, caused by the African Horse Sickness Virus (AHSV). It is primarily transmitted by Culicoides biting midges and is endemic to sub-Saharan Africa.
The disease presents in four forms: pulmonary, cardiac, mixed, and horse sickness fever, with symptoms ranging from severe respiratory distress and swelling to mild fever and swelling around the eyes. The pulmonary and mixed forms have particularly high mortality rates.