Many individuals are unaware that they have HIV in the first few months, as they do not display any symptoms, or only experience mild symptoms (e.g. headache, sore throat, fatigue) that can easily be confused with other illnesses. Despite the lack of symptoms, this initial phase of acute HIV infection is when HIV is most infectious. As the viral load increases, other symptoms appear, including swollen lymph nodes, weight loss, high fever, diarrhea, mouth ulcers, muscle aches, and persistent coughing.
The second stage of HIV infection is known as clinical latency (or chronic HIV infection). The virus is still multiplying during this stage, but only at very low levels, and many individuals do not show any symptoms. However, without HIV treatment, individuals in this stage can still transmit HIV.
HIV targets cells of the immune system reducing the ability to fight other infections and eventually progressing to AIDS (stage 3 of HIV infection) in untreated individuals. The symptoms of AIDS include rapid weight loss, extreme fatigue, pneumonia, skin discoloration, memory loss, depression, and increased susceptibility to other infections such as tuberculosis, severe bacterial infections, and certain cancers.