Gotschlich1 reports three cases of pest pneumonia, which are remarkable, first because terminating in recovery, and second because virulent bacilli remained in the sputum for weeks after apparent recovery. The pneumonic form of pest is nearly always fatal. The significance of the observation lies in the fact that such cases undoubtedly constitute a most dangerous source of infection. The primarily pneumonic localization without bubo can not be diagnosed except by bacteriologic means. The frequency of instances like these and their actual influence in epidemics are for future investigations to determine.
PERSISTENCE OF LIVING, VIRULENT PEST BACILLI IN THE SPUTUM FOR WEEKS AFTER RECOVERY FROM PEST PNEUMONIA.. JAMA. 1900;XXXIV(5):301. doi:10.1001/jama.1900.02460050047010