Tropical diseases area unit diseases that area unit rife in or distinctive to tropical and semitropic regions. The diseases area unit less rife in temperate climates, due partly to the incidence of a chilly season, that controls the insect population by forcing hibernation. However, several were gift in geographical region and northern America within the seventeenth and eighteenth centuries before fashionable understanding of sickness causing. The initial impetus for medical specialty was to safeguard the health of colonial settlers, notably in Republic of India beneath land rule. Insects like mosquitoes and flies area unit far and away the foremost common sickness carrier, or vector. These insects could carry a parasite, microorganism or virus that's infectious to humans and animals. most frequently sickness is transmitted by AN insect "bite", that causes transmission of the agent through connective tissue blood exchange. Vaccines don't seem to be out there for many of the diseases listed here, and lots of don't have cures.