Human Usutu Virus Infection with Atypical Neurologic Presentation, Montpellier, France, 2016

Infection with Usutu virus (USUV) has been recently associated with neurologic disorders, such as encephalitis or meningoencephalitis, in humans.These findings indicate that USUV is a potential health threat.We report an acute human infection with USUV in France putatively associated with a clinical diagnosis of idiopathic facial paralysis. U sutu virus (USUV) is a mosquitoborne flavivirus.This virus was detected in South Africa in 1959 and is maintained through an enzootic cycle involving birds as the main amplifying reservoir hosts and ornithophilic mosquito species as vectors (mainly Culex spp.) (1).Mammals, including humans, are incidental dead-end hosts.Although USUV was considered a tropical or subtropical virus, it was recently introduced in central and western Europe.Emergence of USUV in Europe was reported in Austria in 2001, but retrospective analyses have suggested an earlier introduction because several epizootics and small outbreaks among local birds have been suspected since 1996 (1).In 2016, a large USUV epizootic was reported in Belgium, France, Germany, and the Netherlands (2).The zoonotic potential of USUV was initially described in the Central African Republic and recently confirmed in Europe by reports of neuroinvasive infections caused by this virus (1).Further evidence of probable human infections was demonstrated by seroprevalence studies on healthy blood donor samples: prevalence of 1.1% in Italy (3) and 0.02% in Germany