There are tens of thousands of different infections. They are all transmitted in different ways. But the main reason for infection is close contact with an infected organism. This can be either eating the meat of an infected animal, or ordinary contact with it. Also, many infections are transmitted by airborne droplets, so most often people become infected after visiting public places. There are infections that are transmitted only through blood, so it is not always worth avoiding people who are carriers of certain infections.
One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.