Transmission
According to healthcare experts, infectious diseases caused by microbes are responsible for more deaths worldwide than any other single cause. They estimate the annual cost of medical care for treating infectious diseases in the United States alone is about $120 billion.
The science of microbiology explores how microbes work and how to control them. It seeks ways to use that knowledge to prevent and treat the diseases microbes cause. The 20th century saw an extraordinary increase in our knowledge about microbes. Microbiologists and other researchers had many successes in learning how microbes cause certain infectious diseases and how to combat those microbes.
Unfortunately, microbes are much better at adapting to new environments than are people. Having existed on Earth for billions of years, microbes are constantly challenging human newcomers with ingenious new survival tactics.
- Many microbes are developing new properties to resist drug treatments that once effectively destroyed them. Drug resistance has become a serious problem worldwide.
- Changes in the environment have put certain human populations in contact with newly identified microbes that cause diseases we have never seen before, or that previously occurred only in isolated populations.
- Newly emerging diseases are a growing global health concern. Since 1976, scientists have identified approximately 30 new pathogens.