The foci of the causative agent of erysipeloid at the islands of the Okhotsk sea were of the polyvector and polyhostal character. There were recorded 92 species of the naturally infected by the erysipeloid causative agent invertebrate inhabitants of the sea, fish, amphibia, reptilia, birds, mammals and ectoparasites of the warm-blooded animals. Gamazoid and ixodes ticks, mosquitoes, horse-flies and flees were found to be naturally infected with erysipelotrix. Ixodes persulcatus were found to be capable of infecting albino mice during blood sucking.