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.
Disease in colonial America
Yellow Fever was a disease that caused thousands of deaths, and many people to flee the afflicted areas. It begins with a headache, backache, and fever making the patient extremely sick from the start, and gets its name from the yellow color of the skin, which develops in the third day of the illness. At the end of one week, the afflicted person is either dead or recovering. Yellow Fever is transmitted by mosquitoes, when it bites an infected person it carries several thousand infective doses of the disease making it a carrier for life passing it from human to human.