Seroprevalence of Toscana virus infection in Tunisia

The main objective of this study was to assess the prevalence of IgG antibodies against Toscana virus (TOSV) by an ELISA test and to determine the extent of its circulation in Tunisia.

An indirect ELISA test was performed to detect anti-TOSV IgG. The results were compared to those of an indirect fluorescent antibody (IFA) test.

The survey tested 494 healthy people from various regions of Tunisia by ELISA for anti-TOSV IgG; 47 people (9.5%) were found to be positive. Seroprevalence varied by bioclimatic region and gender. Two hundred and twelve samples, randomly chosen from the same selected population and tested with ELISA, were retested using an IFA for IgG antibodies. An 85% concordance between the IFA and ELISA was obtained (kappa=0.650).

These serological data confirm the circulation of TOSV in different bioclimatic zones in Tunisia where the vector sand flies are found. The detection of IgG against TOSV suggests that the diagnosis of TOSV infection is often neglected, as this virus often causes asymptomatic infections, with only a few patients developing severe illnesses involving neurological manifestations.