Plague also spreads from human to human by inhalation of aerosolised infective droplets, in the absence of flea or animal.

• 香港曾于一八九四年在上环太平山一带爆发一场鼠疫。当时法国科学家耶尔辛氏在香港发现淋巴腺鼠疫的杆菌。