An Outbreak of Mouse Typhoid and Its Attempted Control by Vaccination

In this paper will be described briefly an epidemic of so called mouse typhoid which prevailed with fluctuations for approximately 2{ years in a mouse breeding station maintained at The Rockefeller Institute. The original stock of about 3,000 mice of all ages was procured by purchase and transported en masse to The Rockefeller Institute. The stock was especially valuable because it yielded a relatively high percentage of mice developing so called spontaneous cancers, located in the mammary glands chiefly, but also in other organs. I t is known that the original stock, from which that purchased by The Rockefeller Institute was derived, had previously suffered losses from mouse typhoid. Moreover, to the stock as purchased, there were added from time to time from the outside a mouse showing a spontaneous tumor or other small accessions of healthy stock. The transfer of the mouse stock took place in April, 1918. Nothing especially noteworthy in the fatalities arose to arrest attention until about the middle of September of that year, when an unusual number of deaths among the stock occurred? From this time on, until what may be called the termination of the epidemic period, some 21⁄2 years later, the number of deaths may be regarded as having been abnormally high, although in intervals between the wave-crests, the death rate returned to a level as low as that usually regarded as normal. I t was customary to record all deaths occurring in the stock mice and at the beginning of each month to take a census of the population