Ability of rabies vaccine strains to elicit cross-neutralising antibodies.

Two European Bat Lyssaviruses (EBLV-1 and EBLV-2) have been identified (n > 750 cases) in European bat species. In addition, EBLVs have been detected as "spillover" cases in three humans, one stone marten and four sheep. A further concern is the interaction of companion animals with infected bats and the possibility of subsequent lyssavirus infection. Cat-bat interactions represent approximately 32 % (n = 398) of passive lyssavirus surveillance submissions at the Veterinary Laboratories Agency (VLA) (1987-2004). Cats therefore represent a potentially significant spillover host. This study evaluated the ability of rabies vaccine antibodies to neutralise EBLVs using modified fluorescent antibody virus neutralisation (FAVN) assays (EBLV-1, EBLV-2). We examined vaccinated human, dog and cat sera in two classes; (i) FAVN-CVS titres > or = 0.5-5.0 IU/ml (n = 34, 79 and 54, respectively), and (ii) > 5.0 IU/ml (n = 22, 21 and 32 respectively). Most sera (approximately 80 %) with higher titres were able to neutralise both EBLV-1 and -2 regardless of the vaccine received. Only a proportion of those with low titres were capable of neutralising either EBLV-1 (27-92 %) or EBLV-2 (38-92 %) or both EBLVs (27-79 %). The cat sera constitute the lower end of each range. More animals that had received LEP based vaccines were able to neutralise EBLVs than those that had received PV based vaccines. The continuing occurrence of non-classical lyssaviruses in Europe emphasizes the need for continual surveillance of bats and other species.