Bubonic plague infects the lymph nodes, septicemic plague is in the blood, and pneumonic plague affects the lungs. The Plague of Justinian in the mid-500s is the first recorded plague pandemic in human history. The third plague pandemic began in China in 1855 and continues today. Finding ‘three rare needles in a haystack’However, the strains of plague that did not have the pla gene eventually went extinct. The diminished virulence that the pathogen evolved in response to more of its hosts dying potentially caused these earlier plague pandemics to fizzle out.