final disease stage of HIV whereby the patient's immune system is completely destroyed and the patient suffers from variety of problems.

HIV infection means that a patient is infected with HIV virus. A patient with HIV infection may look completely healthy (asymptomatic carrier state), may have opportunistic infections such as TB, pneumonia or may finally go into full-blown AIDS. AIDS is the condition where the patient's immune system is completely destroyed and the patient succumbs to various infections, has wasting and develops symptoms such as cancers, fever and diarrhea.
REMEMBER, NOT EVERY HIV INFECTED PERSON HAS AIDS.

Over 80% of HIV infection worldwide is sexually acquired.
In children, in addition to the above-mentioned routes of transmission, mother to child transmission during pregnancy, at birth or through breast feeding is the predominant mode of transmission and accounts for almost 80-85% of HIV infection in children.

Soon after contracting HIV, some persons may develop flu like illness with swollen lymph nodes, fever, malaise and rash lasting for 2 to 3 weeks. This is called as Acute (Primary) HIV infection. This stage is usually not seen in children as the primary infection is acquired at the time of pregnancy or at birth due to mother to child transmission.
Following the primary infection, a patient may remain and feel completely healthy. This is known as the asymptomatic stage. This stage usually lasts for 8-10 years in adults. However, in children this stage is shortened. During this stage, the virus is actively replicating in the body but the body's immune system is also working hard to control the infection. Hence the patient remains asymptomatic. In children, the immune system is not fully mature. As a result, the virus soon overcomes the immune system and the patient starts manifesting signs and symptoms of the disease.
Once, the immune system breaks down, patient develops various infections such as TB, Pneumonia, Diarrhea, Herpes zoster etc. The virus may also affect various organs of the body such as lungs, eyes, gastrointestinal tract, brain, heart, liver and skin and cause various organ dysfunctions. During advanced stage of the disease, patient develops unexplained weight loss, fever; infections by unusual organisms and in adults - rare cancers (Lymphoma & Kaposi's sarcoma) can also develop. With development of AIDS, patient usually succumbs to the disease until and unless intervention with drugs is given.