Leg pain is also frequently a sign of injury, such as the following: Muscle strain is a common injury that happens when the muscle fibers tear as a result of overstretching. It often occurs in the larger muscles, such as the hamstrings, calves, or quadriceps.
medical Definition of superinfection : a second infection superimposed on an earlier one especially by a different microbial agent of exogenous or endogenous origin that is resistant to the treatment used against the first infection
People with HIV risk superinfection by the same actions that would place a non-infected person at risk of acquiring HIV. These include sharing needles and forgoing condoms with HIV-positive sexual partners. For many years superinfection was thought to occur mainly in high-risk populations.