what the name of the bacteria that causes the plague
-- Yersinia Pestis. Yersinia pestis are Gram-negative bacteria found in certain parts of the world, causing about 1,000 to 3,000 plague cases each year. Cases of plague most commonly occur in Africa, Asia, and South America. Between 10 and 20 cases of bubonic plague happen in the United States every year, most often in rural areas of the Southwest. Yersinia pestis is found most commonly in rats, but occasionally in other animals.