In the last two decades, several vector-borne diseases have emerged as major causes of human morbidity and mortality. All four serotypes of Dengue virus have emerged in Central and South America and in the Caribbean. Chikungunya has re-emerged on the Indian sub-continent and Japanese encephalitis has been seen for the first time in India and Pakistan. In the last decade, the incidence of tick-borne encephalitis has increased dramatically in Russia, eastern and central Europe and yellow fever has emerged in West Africa.
What are the myriad reasons that faciliate the emergence or re-emergence of vector-borne infectious diseases?