Effects of cortisone on experimental murine typhus. I. Susceptibility of the Syrian hamster to murine typhus and the effect of cortisone.

Investigators who study rickettsial diseases are interested in finding an animal highly susceptible to these diseases. The lack of such an animal has prompted the investigation of numerous animals and the use of various techniques to increase their susceptibility. This is well demonstrated in the literature concerning murine and epidemic typhus. Although the guinea pig, cotton rat, and mouse are in common use in the study of typhus, fatal infections are produced with regularity only when massive doses of viable rickettsiae are injected. In reviewing the literature on animals which have been tested for susceptibility to typhus infection, no references were found regarding the use of the hamster, although this animal has been used in the study of several infectious agents. Lennette (1941) found hamsters susceptible to the viruses of St. Louis and Japanese B encephalitis by cerebral inoculation. Griffith (1939) found the golden hamster susceptible to bovine, human, and avian tubercle bacilli and vole bacilli. Kilham and Overman (1953) showed that suckling hamsters could be used for primary isolation of mumps virus and for serum neutralization tests. Schwartzman and Aronson (1953) have found the cortisone treated hamster useful in studies on poliomyelitis. It is shown in this report that the hamster is only slightly susceptible to murine typhus and that cortisone treatment greatly increases the susceptibility of the animals.