Red foxes (Vulpes vulpes) feeding brown hares (Lepus europaeus) infected by European brown hare syndrome virus (EBHSv) might be involved in the spread of the virus

Carnivores are potential carriers of agents that infect their prey species, even though they themselves are not susceptible, such as the lagovirus that causes European brown hare syndrome (EBHS), a severe disease of brown hares endemic in Europe. During our wildlife surveillance in Lombardy, we identified an EBHS outbreak in a protected area by both virological analyses (sandwich ELISA and RT-PCR) of the target organs from one dead hare and serological examinations (competitive ELISA) of captured animals. Since four red foxes were contemporarily hunted in the same area, we examined their organs by RT-PCR for the EBHS agent (EBHSv). The intestinal content of one fox tested positive, while the fox' other organs (liver, spleen, and mesenteric lymph nodes), and all of the samples from the remaining three foxes, tested negative. Moreover, in the gastrointestinal content of the positive fox, we found food debris that was genetically identified as being of hare origin. The competitive ELISA test for EBHSv antibodies gave negative results in all of the fox sera. Genetic analyses of the EBHSv amplicons obtained by RT-PCR in the hare and the fox indicated a full homology (99.9 % nucleotide and 100 % amino acid identity). These results support the fact that red fox, as other predators, feeding on EBHSv infected hares may have genetic prints of the virus in their gut contents. Even if we did not prove that lagovirus particles remained infective in the excreted feces and, thus, contaminated the ground in the outbreak area, these eventualities cannot be excluded, and we could at least conclude that red foxes might assume a potential role in the indirect transmission of lagovirus, as EBHSv.