How do new pandemic and epidemics arise?

New pandemics and epidemics arise when pathogens, such as viruses or bacteria, jump from animals to humans (a process known as zoonosis), often facilitated by factors like habitat encroachment, wildlife trade, and climate change. Increased global travel and urbanization can further facilitate the rapid spread of these diseases. Additionally, mutations in pathogens can enhance their transmissibility or virulence, leading to outbreaks. Public health infrastructure and responses also play a critical role in managing and containing these emerging threats.