Equine encephalosis virus: evidence for circulation beyond southern Africa

Prior to the recent outbreak of equine encephalosis in Israel in 2009, equine encephalosis virus (EEV) had only been isolated from equids in South Africa. In this study we show the first evidence for the circulation of EEV beyond South Africa in Ethiopia, Ghana and The Gambia, indicating that EEV is likely to be freely circulating and endemic in East and West Africa. Sequence analysis revealed that the EEV isolate circulating in The Gambia was closely related to an EEV isolate that was isolated from a horse from Israel during the EEV outbreak in 2009, indicating that the two viruses have a common ancestry. Interestingly horses in Morocco tested negative for EEV antibodies indicating that the Sahara desert may be acting as a geographical barrier to the spread to the virus to North African countries. This evidence for EEV circulation in countries in East and West Africa sheds light on how the virus may have reached Israel to cause the recent outbreak in 2009.