Long‐term seroepidemiology of European brown hare syndrome in European and Italian hares in Tuscany (Italy)

European brown hare syndrome (EBHS) is a highly contagious disease caused by a virus in the Lagovirus genus, family Caliciviridae (EBHSV – Lagovirus GII.1). First identified in Italy in 1988, it has since spread and become endemic, affecting various species within the Leporidae family. Notably, it has affected the European hare ( Lepus europaeus ), a common species in North and Central Italy, and the Italian hare ( Lepus corsicanus ), a species of conservation concern endemic to Central and South Italy. This study aimed to determine the presence and to assess the occurrence of EBHS in the province of Grosseto (Tuscany, Central Italy), through a longitudinal survey conducted from 2003 to 2019. We carried out a diagnostic investigation using a competitive enzyme‐linked immunosorbent assay (ELISA) on blood samples from 479 European hares and 58 Italian hares, which had been caught and released to restock hunting areas. We determined the distribution of positive anti‐EBHSV titers stratified by age class, sex, species, years of sampling, and the type of establishment where individuals were caught. The results showed that the disease is apparently more widespread among European hares than among Italian hares. We found a higher prevalence in adults than in young individuals, and no differences between males and females. Most sera had low antibody titers, indicating endemic circulation of EBHSV and a high level of within‐population protection. We used a generalized linear model with a binomial distribution and a logit link function to estimate EBHS prevalence, with 5 fixed effects (sex, age, year of sampling, month of sampling, and zone of hunting). The sex effect was not significant, whereas the age effect influenced the probability of infection, which was higher in adults than in young individuals. The winter months (January, February, and March) had a greater probability of EBHSV infection. No precise trend was revealed regarding the year effect, which might be related to the unbalanced experimental design. The data from this survey, spanning over 15 years, contribute to a better understanding of the dynamics of EBHS in an endemic area and may inform intervention strategies and improve the management of hunting areas.