Emergence of<i>Usutu virus</i>, an African Mosquito-Borne<i>Flavivirus</i>of the Japanese Encephalitis Virus Group, Central Europe

TLDR

In late summer 2001, a series of bird deaths in Austria mirrored the early West Nile virus epidemic in the U.S., raising concerns that the emerging virus could impact avian populations in Central Europe and might pose an unknown risk to humans. The researchers necropsied the dead birds, performed pathological and immunohistologic examinations that indicated a West Nile virus infection, and then isolated, identified, partially sequenced, and phylogenetically analyzed the virus. The isolates were 97 % identical to Usutu virus, a mosquito‑borne flavivirus of the Japanese encephalitis group that had not previously been detected outside Africa or linked to fatal disease in animals or humans.

Abstract

Abstract During late summer 2001 in Austria, a series of deaths in several species of birds occurred, similar to the beginning of the West Nile virus (WNV) epidemic in the United States. We necropsied the dead birds and examined them by various methods; pathologic and immunohistologic investigations suggested a WNV infection. Subsequently, the virus was isolated, identified, partially sequenced, and subjected to phylogenetic analysis. The isolates exhibited 97% identity to Usutu virus (USUV), a mosquito-borne Flavivirus of the Japanese encephalitis virus group; USUV has never previously been observed outside Africa nor associated with fatal disease in animals or humans. If established in central Europe, this virus may have considerable effects on avian populations; whether USUV has the potential to cause severe human disease is unknown.