Emerging and re-emerging infectious diseases as public health challenges of the 21st century

Abstract

Infectious and communicable diseases have remained major public health challenges to humankind throughout history (1). These
diseases marked epidemiological series of transitions where the first transition has to do with the rise in infectious diseases; the second transition accompanies a shift from infectious to chronic disease mortality and the third transition is marked by recent resurgence of infectious disease mortality. The emergence and re-emergence of these infectious diseases follow different socio-historical and ecological characteristics.