In a total of 133 patients considered as viral meninqitis or encephalitis on clinical and bacteriological grounds, arboviruus infections was diagnosed in nine cases on the basis of serological results. The associated arbovirus was West Nile in four cases, Sindbis in three cases and Bunyamvera in two cases. Only Sindbis virus was isolated once from an acute serum and once from a throat swab.