People who develop strep throat usually do so because they have come into contact with the droplets of an infected person, Mayo Clinic states. People may also spread strep via the skin, which causes it to enter wounds and cause other types of infection.
When someone is carrying the Streptococcus bacteria and their mucus or spit comes into contact with a non-infected person, the non-infected person may develop an infection. This can happen when the infected person coughs, sneezes or shares a drink. Some people may not show signs of an infection, but because they carry strep in their throat they can pass it onto others, warns the Centers for Disease Control. In addition, some people carry strep on their skin, which they can spread to open wounds.
One of the most common infections caused by streptococcus is strep throat. This is generally mild and does not usually cause severe complications. However, serious conditions like necrotizing fasciitis, pneumonia and streptococcal toxic shock syndrome are also possible. Such conditions usually arise when strep reaches an area of the body where it is not usually present. For example, if it moves down into the muscle, necrotizing fasciitis may arise, which allows the bacteria to quickly destroy the skin and surrounding soft tissues.