Infectious diseases seem to come and go, sometimes causing scary outbreaks, while other times seeming to disappear. But some infectious pathogens are always with us, lurking just below the surface of society.
Sexually transmitted diseases are one major group of diseases that make for ongoing hidden epidemics: In the United States alone, there are nearly 20 million cases of new sexually transmitted infections yearly, from just eight viruses and bacteria. Here is a look at the number of people infected with each of these diseases in the U.S. as a whole, and in each state:
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