The mode transmission of plague, which had long been a mystery, was ultimately resolved in 1905 when it was demonstrated that the plague bacillus ’Yersinia pestis’ (first identified in 1894) was transferred to humans from rats via rat flea bites. Other transmission modes, such as airborne transmission via cough drops in the occurrence of pneumonic plague, were also hypothesized. The advancement of medicines and improved immunity have later made plague a treatable disease. Over time, plague preventive methods have evolved, including “Disinfection, Evacuation, Inoculation, Medical Relief, Public Education, Rat Proofing, Rat Extermination and Improvements in Sanitation.”