We live in a dirty world. Wherever we go, we are among microbes. Bacteria, fungi and viruses live on our phones, bus seats, door handles and park benches. We pass these tiny organisms to each other when we share a handshake or a seat on the plane.
Women with breast cancer have long faced complicated choices about the best course of treatment.
Increased funding, targeted prevention efforts and better treatment have helped to slow down the HIV epidemic in the United States. The number of new HIV-positive cases has decreased significantly, according to the Centers for Disease Control and Prevention (CDC), with the number of new HIV diagnoses declining by 19 percent from 2005 to 2014.