Emerging and re-emerging infections

Abstract

Emerging infections are newly identified infections in humans—and are most often zoonotic—caused by infectious organisms that breach the species barrier between animals and humans. Re-emerging infections are known organisms that infect humans, but are identified after a period of absence from human populations. Re-emerging infections also often result from breaches in the species barrier. In addition to direct health outcomes of sickness and death, they also affect the economy, and may spread globally. This chapter discusses factors that influence the emergence of infectious diseases including weak public health infrastructure; failure of safety procedures and regulations; population shifts including rapid population increases and uncontrolled urbanization; anthropogenic activities and climate change; civil disturbance, human displacement, and natural disasters; human behaviours; and deliberate use to cause fear and harm. To address these threats, national public health systems must be strengthened to detect and respond to infectious diseases when and where they emerge, or re-emerge; and a safety net of global networks is required if and when the countries in which they emerge or re-emerge are unable to stop their international spread.