Usutu virus (USUV) is an emerging zoonotic arbovirus of concern because of its pathogenicity to humans and its similarity in ecology with other emerging arboviruses such as West Nile virus. USUV is a flavivirus belonging to the Japanese encephalitis complex.
USUV’s host range includes primarily Culex mosquitoes, birds, and humans.
USUV has been reported from several African countries including Senegal, Central African Republic, Nigeria, Uganda, Burkina Faso, Cote d’Ivoire, and Morocco. Only two human cases have been identified in Africa, in 1981 and 2004, with one benign and one severe case described. The first human case outside of Africa was reported in Italy in 2009, where an immunocompromised patient was infected, causing encephalitis.