In the past, this disease caused great problems in other areas of the world. Epidemics during the Spanish American War, and particularly the epidemic in Philadelphia in the 19th century, killed thousands of people. Early in the 20th century, scientists discovered the cause of yellow fever, and soon afterward, a vaccine was developed that has essentially eradicated the disease in the US and other parts of the world. Vaccines are less available to people in poorer areas. Thus parts of Africa and South America are prime targets for contracting the disease because people do not have the vaccine available, but in modern day society vaccinations and precautions are given and it is lease more likely for someone to catch the deadly disease.
