QUANTIFICATION OF RESIDUAL VIRULENCE OF T HE VNUKOVO-32 107 RABIES VIRUS VACCINATION STRAIN/

The present work summarizes the results of 11 groups of experiments ca rried out with the aim to complexly quantify the residual virulence of a cold mutant of the Vnukovo-32/107 rabies virus vaccination strain i ntended for the preparation of an oral rabies vaccine (Kamark) for the immunization of free-living carnivores. According to WHO prescription s, residual virulence was quantified in experiments on carnivores, mai nly red foxes (Vulpes vulpes) - the presumed target species, and farm- bred polar foxes (Alopex lagopus) - a related species. Further experim ents were carried out in cats, dogs, non-target autochthonous micromam mals, predatory birds (Microtus arvalis, Apodemus flavicollis, Falco t innunculus) and in a large number of laboratory animals - white mice. At oral administration (including extremely high doses) the strain Vnu kovo-32/107 proved to be apathogenic to the target carnivores - Vulpes vulpes and Alopex: lagopus as well as cats, dogs and the autochthonou s micromammals. For Falco tinnunculus the strain proved to be apathoge nic even at intramuscular and intracerebral administration. The residu al virulence of the Vnukovo-32/107 vaccination strain, also quantified by comprehensive model experiments on white mice of different weight categories that had been infected orally, subcutaneously, intramuscula rly, intracerebrally, by contact, with ingestion of rabic material or by modelled immune suppression, proved to be extremely low-levelled. T he strain under investigation revealed a high level of attenuation and a low level of residual virulence and proved to be suitable for the p reparation of non-reactogenic oral vaccine intended for foxes, an extr emely susceptible target species.