Toscana virus (TOSV) exposure is confirmed in blood donors from Central, North and South/Southeast Anatolia, Turkey

Toscana virus (TOSV), a sandfly fever virus serotype of medical and public health importance, is a major pathogen involved in aseptic meningtis occurring in Mediterranean countries and poses a threat to the residents as well as travellers. Limited data on TOSV activity are present from Turkey despite being located in the endemic zone. We aimed to identify TOSV exposure in 1115 healthy blood donors at the Hacettepe University Hospital Blood Bank in Ankara, Turkey, using commercial indirect fluorescence assays (IFAs) and virus neutralization test (VNT) for antibody detection and specificity confirmation. A total of 199 samples (17.8%) were positive for anti-TOSV that include IgG reactivity in 10.4%, IgM reactivity in 8.2% and IgM + IgG reactivity in 0.7% of the sera. Anti-TOSV specificity could be confirmed via VNT in 56% of the IgG- and 43.6% of the IgM-positive sera, making up a total of 58 samples (5.2%). Risk factors associated with TOSV IgG reactivity were male gender, residing in rural areas, frequent sighting of mosquitoes/sandflies and working outdoors. TOSV-specific antibody prevalence increased significantly with age. Evidence of exposure to other sandfly fever viruses was noted. These data reveal that mild or asymptomatic infections with TOSV are frequent in central and northern Anatolia. TOSV exposure has also been identified in residents of 9 provinces in southern/southeastern Anatolia for the first time.