http://en.wikipedia.org/wiki/Carlos_Finlay

It was a Cuban, Dr Carlos Finlay, who first suggested the link between mosquitoes and yellow fever, even identifying the responsible species. He was able to confirm that link with geographical and epidemiological studies, but the long incubation period of the microorganism made it imposssible for him to prove a direct link using human volunteers. US doctor Walter Reed ran the volunteer program that finally settled the question, and he is generally given credit in the USA for this discovery.

His hypothesis and exhaustive proofs were confirmed nearly twenty years later by the Walter Reed Commission of 1900. Finlay went on to become the chief health officer of Cuba from 1902 to 1909. Although Dr. Reed received much of the credit in history books for "beating" yellow fever, Reed himself credited Dr. Finlay with the discovery of the yellow fever vector, and thus how it might be controlled. Dr. Reed often cited Finlay's papers in his own articles and gave him credit for the discovery in his personal correspondence.

Although Dr Reed certainly acquitted himself honorably in this issue, the Cubans never forgave the Americans (actually, the Hearst press) for stealing credit for the discovery that saved so many lives worldwide, and made the construction of the Panama Canal possible.

Dr. Finlay was a member of Havana's Royal Academy of Medical, Physical and Natural Sciences. He was fluent in French, German, Spanish, and English, and could read Latin. His interests were widespread and he wrote articles on subjects as varied as leprosy, cholera, gravity, and plant diseases. But his main interest was yellow fever, and he was the author of 40 articles on this disease. His theory that an intermediary host was responsible for the spread of the disease was treated with ridicule for years. A humane man, he often took on patients who could not afford medical care. As a result of his work, Dr. Finlay was nominated seven times for the Nobel Prize in Physiology or Medicine, but it was never awarded to him. He received the National Order of the Legion of Honour of France in 1908.