Mosquito
Mosquito-borne diseases are currently most prevalent in East Africa, Latin America,  Southeast Asia, and India; however, emergence of vector-borne diseases in Europe have recently been observed. A weighted risk analysis demonstrated associations to climate for 49% of infectious diseases in Europe including all transmission routes. One statistical model predicts by 2030, the climate of southern Great Britain will be climatically-suitable for malaria transmission "Plasmodium vivax" malaria for 2 months of the year. By 2080 it is predicted that the same will be true for southern Scotland.
Carlos Finlay
Finlay's work, carried out during the 1870s, finally came to prominence in 1900. He was the first to theorize, in 1881, that a mosquito was a carrier, now known as a disease vector, of the organism causing yellow fever: a mosquito that bites a victim of the disease could subsequently bite and thereby infect a healthy person.
He presented this theory at the 1881 International Sanitary Conference, where it was well received. A year later Finlay identified a mosquito of the genus "Aedes" as the organism transmitting yellow fever. His theory was followed by the recommendation to control the mosquito population as a way to control the spread of the disease.
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.