Studies on the Tyzzer's Disease in Mice

1. Epizootiologicol Observation

Abstract

Since TYZZER described the disease in Japanese waltzing mice in 1917, it has been revealed that the infection is widespread among mouse colonies in Europe and the U. S. A.
However, in Japan the Tyzzer's disease was first described recently by KANEKO et al. and IMAI and general aspects of the infection among Japanese mouse colonies are still unknown.
In August 1960, authors observed an outbreak of the disease in mice of so-called dd strain derived from a farm. Pathological and bacteriological examinations were performed concerning to this outbreak and some other reproducing colonies were surveyed in order to detect the subclinical infection. The results obtained are summarized as follows:
1. Acute or subacute disease observed in so-called dd mice, was identified with the Tyzzer's disease histopathologically. Characteristic necrosis of liver parenchyme was accompanied with intracellular configuration of bacilli. The disease seemed to run also in mild or chronic type (Table 1) .
2. Culture of pathogenic organisms was not obtained by any media used for the isolation. It was noticed that Lactobacilli were isolated more frequently from infected livers than non-infected ones (Table 2) .
3. Intravenous or intraperitoneal infection of mice with infected liver materials succeeded only when accompanied with cortisone acetate administration. (Fig. 1) .
4. The survey performed in a certain prefecture revealed that 6 out of 10 reproducing mouse colonies were contaminated subclinically. Fifty-four out of 482 (11.2%) mice examined showed positive liver lesions (Table 3) .
5. It was suggested that environmental conditions could be related to the infection of the disease (Fig. 1, Fig. 4) .