For instance, formerly dry areas may become excellent habitats for parasite-carrying insects as well as for snails and other animals that serve as parasite hosts. I ncreased trade and expanded markets for imported foods, which occasionally contain bacterial or viral contaminants. Although modern large-scale food technologies generally improve food safety, when contamination does occur, it may affect large numbers of people. Continual evolution of pathogenic microorganisms. The modern world is a very small place, where any city in the world is only a plane ride away from any other.
Infectious microbes can easily travel across borders with their human or animal hosts.
In fact, diseases that arise in other parts of the world are repeatedly introduced into the United States, where they may threaten our national health and security. Without preventive public health measures in the United States and abroad, uncontrolled outbreaks can grow into major epidemics. However, our earlier successes in controlling infections have bred complacency, and the components of the U.S. public health system that protects the public from infectious microbes have been neglected, concentrating their resources on a few targeted diseases. Nevertheless, the subject of emerging infectious diseases is beginning to receive sustained public attention. This media attention has informed the American public of the reasons why it is in our national interest to strengthen disease surveillance and control efforts internationally.