One scientific discovery that changed the field of microbiology, sanitation, and disease prevention forever was Carlos Juan Finlay’s discovery that the tropical disease yellow fever was spread by mosquitoes, especially the Aedes aegypti mosquito. Finlay was born in Camagüey, Cuba on December 3, 1833. He had a diverse education, studying in both France and America. During his time, yellow fever was ravaging and decimating the population of tropical areas, including his home country of Cuba. It is ironic that the man who determined that yellow fever was transmitted by mosquitoes succumbed to multiple diseases throughout his life. After contracting cholera and almost dying from typhoid fever, he returned to Cuba where he practiced medicine. Throughout