Studies on Certain Biological Characteristics of Malleomyces mallei and Malleomyces pseudomallei

Abstract

The various strains of the organisms studied varied greatly in their virulence. The strains of low virulence tended to produce subacute or chronic forms of the diseases, whereas strains of high virulence produced acute fulminating infections. The virulence of one strain was increased by serial passage in hamsters. Hamsters were easily infected by inoculation by the intraperitoneal, subcutaneous, and respiratory routes. Oral inoculation gave irregular results, but some animals became infected after ingestion of small doses. Of the laboratory animals tested, hamsters were found to be the most susceptible. The MLD in hamsters was 15 to 20 organisms of virulent strains. Ferrets were also very susceptible, but guinea pigs were only moderately susceptible and individual animals varied greatly in the degree of susceptibility. Rabbits, mice, rats, and monkeys were least susceptible.