In 1905, yellow fever was reported in the city, which had suffered under repeated epidemics of the disease in the previous century. As the role of mosquitoes in spreading the disease was newly understood, the city embarked on a massive campaign to drain, screen, or oil all cisterns and standing water (breeding ground for mosquitoes) in the city and educate the public on their vital role in preventing mosquitoes. The effort was a success and the disease was stopped before reaching epidemic proportions. President Theodore Roosevelt visited the city to demonstrate the safety of New Orleans. It has had no cases of Yellow Fever since.