Black Death still exists.
Just because the massive Black Plague disappeared because it had no living human hosts in which to survive. However, the infection managed to stay in rodents, fleas, or warm places that act as reservoirs. The plague repeatedly bounced back up in Europe and the Mediterranean throughout the 14th to 17th century, but in smaller degrees. The Third plague pandemic lasted from 1855-1959, and started in China.
The first North American plague epidemic was the San Francisco plague of 1900-1904, following 1907-1908. The plague was confirmed in the US from 9 western states during 1995. Currently, 5 to 15 people in the United States are estimated to catch the disease each year, typically in western states.