[Emerging and reemerging diseases].

Emerging and reemerging diseases are the result of the interaction of multiple factors, such as social determinants of health, climate change, and conditions that prevail and are identifiable in some populations. As a consequence, there may be situations that by their nature are defined as a health emergency, impacting directly on the health of a population, either because they are not known or due to their rapid spread, resulting in a health security problem. Examples of these diseases are described in this article, starting with their origin, their impact on the population, and the response necessary in order to contain or prevent damage of a greater magnitude. The presence of these agents and their consequent damage to the population should lead efforts towards comprehensive prevention and appropriate containment strategies to ensure the protection of public health. Endeavors should be directed not only to a specific agent, but rather to factors that determine their reemergence, such as Ebola, or their permanence, such as the binomial infection of tuberculosis-AIDS. In order to correctly implement strategies, training and availability of supplies play a crucial role in facing the challenges that lie ahead.