Prevalence of antibodies to phleboviruses within the sand fly fever Naples virus species in humans, northern Greece

Phleboviruses are commonly detected in the Mediterranean region. In order to estimate the seroprevalence to Toscana virus (TOSV) and TOSV-like viruses in the human population in northern Greece, we tested serum samples from 595 apparently healthy individuals aged 1–87 years (median: 45 years) for the presence of TOSV IgG antibodies. A seroprevalence of 11.26% was observed, ranging from 0% to 23.5%. Seropositivity was significantly lower in children and adults <30 years of age. The high seroprevalence (<10%) observed in several prefectures of northern Greece suggests that an important proportion of infections caused by TOSV or TOSV-like viruses may be asymptomatic or mild, and therefore underestimated. Increased awareness of physicians is needed during the summer months, when sand flies are active and have the potential to transmit phleboviruses to humans.