HEALTH Scientists may have found the oldest-ever evidence of the plague, locked away in an 20-million-year-old flea. (Washington Post) See more fleas and other bloodsuckers in our fantastic photo gallery. Discussion Ideas The Washington Post article lists three major infections known as the plague: bubonic plague, pneumonic plague, and septicemic plague. What is the difference? The major difference is where the infection is located. Bubonic … Continue reading Plague’s Patient Zero?