Plasmodium vivax
Plasmodium vivax is a protozoal parasite and a human pathogen. This parasite is the most frequent and widely distributed cause of recurring (Benign tertian) malaria, "P. vivax" is one of the five species of malaria parasites that commonly infect humans. Although it is less virulent than "Plasmodium falciparum", the deadliest of the five human malaria parasites, "P. vivax" malaria infections can lead to severe disease and death, often due to splenomegaly (a pathologically enlarged spleen). "P. vivax" is carried by the female "Anopheles" mosquito; the males do not bite.
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.