Intracutaneous Anthrax Infection in Wild Rodents

1. Experiments designed to test the effect of intracutaneous anthrax infection in 12 species of native Utah rodents are described. 2. In the following species an inoculum of 80 virulent Bacillus anthracis spores was sufficient to cause death of all animals tested : Peromyscus maniculatus, Peromyscus crinitus, Peromyscus truei, Reithrodontomys megalotis, Neotoma lepida, Perognathus formosus, Perognathus parvus and Citellus leucurus. 3. The kangaroo rats (Dipodomys ordii and Dipodomys microps) were resistant to as many as 40,000 spores. 4. The exact degree of susceptibility could not be established for the cliff chipmunk (Eutamias dorsalis) and the grasshopper mouse (Onychomys leucogaster) because of the limited number of animals available. The results indicate that these two species are of intermediate susceptibillty between the very susceptible small mice and the more resistant kangaroo rats. 5. The cutaneous lesions elicited by intracutaneous injection of anthrax spores in the twelve species of rodents tested are described and illustrated with five photographs.