SUSCEPTIBILITY OF SOME SPECIES OF STEPPE RODENTS TO ARTIFICIAL INFECTION WITH WEAKLY VIRULENT PLAGUE STRAINS ISOLATED IN TRANSBAYKALYA

Preliminary data obtained in testing susceptibility of several steppe rodents and laboratory animals to artificial inoculation by plague bacillus strains showed that all these strains are weakly virulent for most of the animals tested and behave as avirulent with respect to guinea pigs and tarbagany. White mice showed the highest sensitivity to inoculation, where even from relatively low doses lethally progressing infection with impregnation of tissues and organs by bacilli developed. It was possible to observe the same kind of acute process in individual cases of Brandt voles, in Daurskiye susliks, and Mongolian jerboas when these animals were infected with doses of from 3,000, 000,000 bacilli and higher. Bascillary impregnation of organs and tissues of the inoculated animals succumbing upon the development of infectious process proved as a rule to be significant and easily detected not only in the culturings, but also in the impression-smears made upon autopsy of the succumbed rodents, and also in histological sections. Trans. of Nauchno-Issledovatelskii Protivochumnyi Institut Sibiri i Dalnego Vostoka, Irkutsk. Izvestiya (USSR) v25 p34-46, 1963.