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HIV and AIDS (human immunodeficiency virus; acquired immunodeficiency syndrome)

HIV cells in blood stream
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What is HIV and AIDS?

HIV AIDSHIV is a retrovirus that causes AIDS. HIV attacks the immune system. This system consists of cells and organs that protect the body against diseases like infections and cancer. HIV attacks the immune system through special types of white blood cell known as CD4 cells. CD4 cells play an important role in orchestrating and controlling the functions of the whole immune system.

Once HIV is in the immune system, it multiplies inside the CD4 cells, disabling and killing them in the course of the infection, and thus interfering with their normal function. The immune system gradually deteriorates until it reaches a point where it can no longer fight off any infection.

The infected person frequently gets infections and even some forms of cancer which a healthy immune system would have gotten rid of quite easily. These infections are known as opportunistic infections. HIV infection, once established, cannot be eliminated by the body or by drugs.

Statistics on HIV and AIDS

According to the 2006 report on the Global AIDS Epidemic by the Joint United Nations Programme, approximately 37.2 million adults and 2.3 million children were living with HIV at the end of 2006. During 2006, some 4.3 million people became infected with HIV, and approximately 2.9 million deaths resulted from HIV/AIDS.

By 30 June 2006, 25,703 people in Australia were infected with HIV, 9,827 had AIDS and 6,621 died as a result of HIV/AIDS. NSW had the highest number of deaths, followed by Vic, QLD, WA, SA, ACT, NT and TAS.

Risk factors for HIV and AIDS

HIV can be transmitted through the following routes:

Progression of HIV and AIDS

Throughout the disease, viral load steadily increases and immunodeficiency progressively worsens (due to the decreasing CD4 count), thereby causing HIV/AIDS to manifest in stages. The World Health Organization (WHO) has categorised HIV disease into 4 stages:

  • Stage I (also known as primary HIV infection): In this stage, the person has no symptoms whatsoever and may not be aware they are infected;
  • Stage II (also known as clinically asymptomatic stage): This stage may last for 8-10 years with no major symptoms except for swollen glands (lymph nodes), some weight loss, mouth ulceration and mild skin and nail infections;
  • Stage III (also known as symptomatic HIV infection): By this stage, the immune system is significantly affected and the infected person now begins to manifest many symptoms, such as severe weight loss, chronic diarrhoea, persistent fever, tuberculosis, severe bacterial infections (e.g. pneumonia and meningitis);
  • Stage IV (also known as AIDS): The immune system is now severely damaged and the symptoms become even more severe. The person is now severely wasted, has severe recurrent bacterial infections, develops cancers such as Kaposi sarcoma, and other infections like Pneumocystis carinii pneumonia (PCP), toxoplasmosis and HIV encephalopathy.

Symptoms of HIV and AIDS

HIV AIDSThe presentation of HIV depends on the stage of the disease that the patient is in. In the early stages of the disease there may be few or no (mild) infections, while in the later stages there may be more severe infections and even some forms of cancer.

Clinical examination of HIV and AIDS

On examination, the following may be found:

How is HIV and AIDS diagnosed?

  • Full blood count: This is a test to check on the levels of white blood cells, red blood cells, platelets and haemoglobins in your blood. This test needs to be done before and regularly after treatment to check for anaemia (reduced blood haemoglobin) and reduction of other blood cells;
  • Urea and electrolytes: These are chemical compounds normally found in blood. Their levels are controlled by the renal system. This test is done to check on the condition of the kidneys. If the kidneys are functioning normally, then the levels of urea and creatinine will be normal. Otherwise the levels will be elevated;
  • Hepatitis B and C testing: HIV patients are at high risk of hepatitis B and C infections, which are also contacted through blood.

Prognosis of HIV and AIDS

It takes about 8 to 10 years from initial infection and symptom manifestation to the development of AIDS. Once AIDS has developed, untreated disease results in death in about 20 months. Treatment with HAART can prolong life and delay disease progression, and improve quality of life.

How is HIV and AIDS treated?

Treatment of infected patient

  • Aim is to stop virus spread permanently;
  • Monitor blood viral load and CD4 count;
  • Start antiretrovirals early before immunodeficiency sets in;
  • Use three antiretrovirals (two nucleoside analogue reverse transcriptase inhibitors and a protease inhibitor);
  • Change to a new combination if viral load rebounds.

More information

Sexually transmitted infections (STIs)For more information on different types of sexually transmitted infections, prevention of STIs, treatments and effects on fertility, see Sexually Transmitted Infections (STIs).

HIV and AIDS prevention

Protection during intercourse (condoms), blood screening, disposable instruments.

For birth: prophylaxis and consider caesarean section, formula feeding.


  1. How HIV causes AIDS [online]. Bethesda, MD: National Institute of Allergy and Infectious Diseases; 2004 [cited 26 February 2007]. Available from: [URL Link]
  2. Kumar P, Clark M (eds). Clinical Medicine (5th edition). Edinburgh: WB Saunders Company; 2002. Book
  3. Scosyrev E. An overview of the human immunodeficiency virus featuring laboratory testing for drug resistance. Clin Lab Sci. 2006;19(4):231-45. Available from: [Abstract]
  4. AIDS epidemic update: Special report on HIV/AIDS: December 2006 [online]. Geneva: UNAIDS; 2006 [cited 26 February 2007] .
  5. 2006 HIV, viral hepatitis and sexually transmissible infections in Australia annual surveillance report [online]. Darlinghurst, NSW: Kirby Institute; 2006 [cited 26 February 2007]. Available from: [URL Link]
  6. Bean P. New drug targets for HIV. Clin Infect Dis. 2005;41(Suppl 1):S96-100. Available from: [Abstract]
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Posted On: 1 August, 2003
Modified On: 20 October, 2013
Reviewed On: 24 January, 2008


Created by: myVMC