The existing COVID-19 pandemic is an anthropogenic disaster which looked inevitable, because despite repeated natural warnings no attention was paid to them. Recently many viral zoonotic infections – caused by SARS-CoV-1, Ebola and Nipah, to name a few – happened that became public health emergency. The most recently discovered zoonotic SARS-CoV-2 is responsible for the contemporary humanitarian disaster. When a virus undergoes zoonotic transmission, the humans begin to respond urgently to its testing and treatment, giving least attention to the actual cause behind the transmission. To prevent future outbreaks, and possible pandemics, it is indispensable to understand the reasons behind emergence of new infectious diseases in human beings. Some most likely reasons for emergence and reemergence of novel zoonotic infections include deforestation, land use change, wildlife trade, bush-meat consumption and rapid increase in international travel. This article attempts to explore and discuss the factors that trigger emergence and reemergence of novel infectious diseases, with special emphasis on SARS, in human beings.