Usutu virus
Usutu virus first identified in South Africa in 1959, 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 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 virus was identified for the first time outside of Africa in 1996 in Italy, where it caused significant mortality among Old World blackbirds. The first human case outside of Africa was reported in Italy in 2009, where an immunocompromised patient was infected, causing encephalitis.
USUV's host range includes primarily Culex mosquitoes, birds, and humans. A 2008-2009 survey of mosquitoes and birds in Emilia-Romagna detected USUV in 89 Culex pipiens pools and in 2 Aedes albopictus pools. Twelve wild birds, primarily European Magpies, Hooded Crows, and Eurasian Jays, were determined to be USUV-positive. USUV detection in mosquito species confirms the role of Culex pipiens as the main vector and the possible involvement of Aedes albopictus in the virus cycle.
