Before germaphobes swear off kissing forever, it should be noted that over 100 trillion microorganisms naturally live in our bodies. Called the microbiome, they are vital for digesting food, synthesizing nutrients and preventing disease… Click here for more

Human immunodeficiency virus (HIV) is a virus spread through body fluids that affects specific cells of the immune system, called CD4 cells or T cells. Over time, HIV can destroy so many of these cells that the body cannot fight off infections and disease… Click here for more.