Vector diseases such as plague, typhus, malaria, yellow fever, and dengue fever, transmitted between humans by blood-feeding arthropods, are common in many parts of the world today. Illnesses that may be transmitted to humans from wild animals continue to circulate in nature, with most vector-borne diseases exhibiting a distinct seasonal pattern, in other words, are weather sensitive. Rainfall, temperature, and other weather factors affect both the vectors and the viruses they transmit in many ways. The accelerated growth in international travel increases the chances of importation of vector-borne diseases, some of which can be thrive locally under suitable circumstances and may even evolve to a different version of the virus. But demographic and sociologic factors also play a critical role in determining disease incidence, and therefore in order to prevent a major epidemic, keeping public health infrastructure maintained and improved should remain top priority.