HIV and AIDS: symptoms and treatments

There are two main types of Human Immunodeficiency Virus (HIV): HIV-1 and HIV-2. These are retroviruses and possess an enzyme (reverse transcriptase) that allows them to copy their genetic material and incorporate it into the DNA of a human cell where it lies 'hidden' and protected from immune attack.

HIV selectively invades the immune cell known as a T-helper lymphocyte (also known as T4 or CD4 cells) in which it multiples and, in some cases, destroys the cells or stops them working properly. T4 cells are essential for regulating the activity of other immune cells, and are especially important for triggering the production of antibodies from B lymphocytes.

How HIV is transmitted?
Through contact with infected body fluids such as blood, urine, semen, breast milk and saliva.

HIV may be spread in a number of ways including:

• unprotected sexual contact with a carrier
• from mother to baby in the womb or during birth
• receipt of infected blood via transfusion - blood in the western world is routinely screened but transfusions further abroad may be a route of transmission
• drug abusers sharing needles
• needle stick injury
• collision injury with a carrier during contact sport
• assault (e.g. human bite)
• contact with contaminated items such as toothbrush, shaver
• wet kissing with exchange of saliva, although this risk is thought to be low

Infection is NOT passed on through normal day-to-day activities such as hugging, dry kissing, shaking hands or sharing cutlery or cups.

What HIV symptoms will you notice?
A few weeks after infection with HIV, some people develop a flu-like illness lasting from one to three weeks. This is usually dismissed as a non-specific 'virus'. Symptoms include fever, headache, joint and muscle pains, lethargy, sore throat, mouth ulcers, swollen glands and sometimes a pink rash.

If blood tests are taken at this stage, they may show low levels of T-helper cells and other abnormal findings such as raised liver enzymes. This illness is usually associated with the production of anti-HIV antibodies (i.e. you become HIV-antibody positive - commonly known as HIV positive).

Most people who are HIV positive remain healthy for many years, but are still highly infectious. Others develop vague symptoms such as slight swelling of lymph glands, weight loss, night sweats or unexplained diarrhoea. These symptoms are known as AIDS-related complex (ARC).

Most people who are HIV positive are unaware of the fact and may therefore pass on the infection to others.