I know for sure one group would be merchants. They were the ones travelling to potentially infected areas---buying things with the plague's germs, and selling it to people on areas that WEREN'T previously infected. Sailors too I believe, for very similar reasons and because rats were infected, and rats caught rides on ships and spread the disease wherever the ship docked.
Hope this helped. :)
It was considered a turning point, because at the time the U.S. was in the American-Spanish war. It took place from April to August in 1898. the war ended in victory for the United States and the end of the Spanish Empire in the Pacific and <span>Caribbean</span>. Only ~113 days after the outbreak of war, the Treaty of Paris, which ended the conflict, gave the United States control over the former Spanish colonies of Puerto Rico, the Philippines and Guam, and control over the process of independence of Cuba, which was completed in 1902.
Is too dangerous just for the sake of rating.