Susceptibility of the Hamster to Tuberculous Infection.

The white mouse is known to be extremely resistant to both the bovine and the human strains of the tubercle bacillus. Koch found the field mouse more susceptible than the white mouse, but it is not known with what species of field mouse he worked. Certainly is was not the striped hamster, which is not found in Central Europe.

The striped hamster (Cricetulus griseus) is very susceptible to infection with Leishmania donovani and these micro-organisms seem to mobilize the same type of cell that is mainly concerned in phagocytizing tubercle bacilli and initiating tubercle formation. So it was but natural to wonder if the hamster is not susceptible to tuberculous infection. The experiments here cited show this to be the case.

Known bovine and human strains of tubercle bacilli have been introduced by the subcutaneous, intra-abdominal and oral routes. The guinea pig was used chiefly to test the pathogenicity of the strains employed, as it is known to react to infection in a more or less uniform way. In the subcutaneous and intra-abdominal inoculations, homogeneous suspensions of 0.1 mgm., dried weight, of tubercle bacilli were administered to hamsters and white mice, and 1.0 mgm. to guinea pigs, as the weight of the latter was approximately ten times that of the former. In the feeding experiments an excess of tubercle bacilli was mixed with the feed, no attempt being made to measure the amount ingested. One animal of each series was sacrificed weekly. At autopsy gross studies were made, and microscopic examination of sections of lung, liver, spleen and tracheo-bronchial lymph nodes was done, and it was found that after six weeks of infection a gross diagnosis of tuberculosis of the lungs could be made in nearly every hamster, whereas this could not be done in the majority of the white mice.