How can global travel affect the spread of infectious diseases?

Global travel significantly influences the spread of infectious diseases, particularly by facilitating the introduction of pathogens into new geographic areas where they may not have previously existed. When individuals travel from one region to another, they can carry infectious agents that may be endemic to their origin but not present in the destination, thus potentially leading to outbreaks. This is especially true for diseases that are easily transmissible and have asymptomatic carriers who do not show symptoms but can still spread the infection.

The dynamics of human mobility mean that once a disease enters a new area, it can find a population that may lack immunity, enabling the pathogen to spread rapidly. Historical examples include the spread of diseases like Zika virus, Ebola, and COVID-19, which have all shown how interconnected global travel networks can facilitate the rapid dissemination of illnesses across borders.