PRELIMINARY NOTE ON THE EXPERIMENTAL INFECTION WITH THE RINDERPEST VIRUS IN SUSLIKS

Abstract

In Mongolia and Manchuria, the rinderpest prevails among cattle, from time to time occurring here and there and spreading over epizootically. This led us to suppose that there may be a connection between the disease and the natural environment.
It is a fact well-recognized in Mongolia that the rodent called "tarabagan" exists infrequently as the carrier of human pest and occasionally it becomes the cause for the outbreak of this terrible epidemic. Such an analogy led us to doubt that Citellus mongolicus ramosus Thos., the suslik most widely distributed in Mongolia and Manchuria, is the carrier of rinderpest-virus.
In 1927 we tentatively inoculated a suslik subcutaneously with 2.0c.c. of the blood of rinderpest calf (No. 56). The animal thus treated showed a rise of temperature and died 7 days after inoculation. The post-mortem examination revealed hemorrhages and ulcers on the mucous membrane of its stomach as well as the dilated gall-bladder filled with dark-blue gall. Five days later the emulsion (1:10) of its lung and spleen, 20c.c. and 15c.c. respectively, was subcutaneously introduced into an aboriginal calf. The latter contracted the typical infection of rinderpest and died after 10 days (Temperature Chart I).
Eucouraged by the result stated above, in 1928 we tried the passage of virus through susliks and carried it on up to the 24th generation (Temperature Charts of Susliks), after every several passages the infection of susliks used for experiment being tested by the inoculation of their materials into calves (Temperature Charts II-VIII). Here it is worthy to note that, as the passage goes on, the number of individuals showing no fever out of inoculated susliks increase and after the 5th generation such a tendency becomes especially conspicuous. If materials from susliks apparently resisting inoculation are injected into calves, however, thus treated calves always succumb to the typical infection. And when the blood and spleen from susliks of the 24th passages were inoculated into 2 calves, both contracted the decided infection of rinderpest (Temperature Charts VII & VIII).
From the foregoing experiments, it may be concluded that the suslik, as the ruminant and swine are, is also susceptible to the rinderpest-virus and occasionally can become the virus-carrier. If such a fact takes place in nature, there may be the outbreak of rinderpest due to the suslik as virus-carrier in Mongolia and Manchuria.