Human cases of Wesselsbron disease, South Africa 2010-2011

Wesselsbron disease is a neglected, mosquito-borne zoonotic infection reported from Africa. The disease primarily affects sheep and other ruminants with incidental spillover to humans. As for other arboviral diseases in Africa, little or no active surveillance is conducted, and the public and veterinary health burden of this disease remains unclear. We report on the clinical histories of 2 human cases of Wesselsbron disease that were laboratory confirmed during the 2010-2011 Rift Valley fever outbreak investigation in South Africa. This report describes the first confirmed human cases of Wesselsbron disease since 1996. Molecular sequencing and analysis of the partial NS5 gene of the Wesselsbron genome was used to identify 2 circulating clades of the virus in southern Africa. Clade I included isolates collected from South Africa and Zimbabwe, whereas clade II only included isolates from the KwaZulu Natal Province of South Africa.