Page updated 30 April 2007
Human Immunodeficiency Virus (HIV)
Introduction
Infection with the HIV has a wide spectrum of clinical expression. Acute infection leads to a self-limiting glandular fever-like syndrome in about 5% of patients, after an incubation period of about 6 weeks. After a very long latent interval (median 10 years), most patients develop severe impairment of the cell-mediated immune system, which may ultimately result in infections by organisms of low virulence (opportunists), and/or the development of unusual malignant tumours (e.g. Kaposi's sarcoma or certain lymphomas). Patients who are diagnosed as suffering from either or both conditions are classified as having developed the Acquired Immune Deficiency Syndrome (AIDS). Others may be infected but can remain completely asymptomatic.
Evidence of infection is usually demonstrated by the detection of antibodies to HIV in the patient's blood. Tests for the presence of HIV RNA or antigen may also be performed when it is necesssary to diagnose a suspected acute or primary infection. Seroconversion (when HIV antibodies can be detected) usually occurs after 6-8 weeks of infection, although studies have shown that rare infected individuals may not produce antibodies until a year after exposure. However, patients who have been infected by the virus are potentially infectious to others whether or not they have clinical symptoms or antibodies.
The epidemiology of HIV infection is similar to that of Hepatitis B. In hospital, the principal risk of transmission to health staff is by inoculation accident. Contamination of skin and mucous membranes by blood or body fluids is a theoretical risk.
High Risk Patient Groups
- Known HIV infected patients
- Homosexual and bisexual men, those with many sexual partners, sex industry workers
- Injecting drug abusers who share equipment
- Haemophiliacs
- Patients from areas of the world where the disease is prevalent (particularly tropical Africa)
- Sexual partners of any of the above
- Children of high risk and HIV-infected individuals
It is now recognised that many patients will present with AIDS associated opportunistic infection without giving a history suggestive of any particular risk.
Patient Management
Most patients with known or suspected HIV infection may be safely nursed in a general ward. However, it is considered prudent to Source Isolate the following in a single room:
- Patients who are likely to bleed or have open wounds or lesions
- Patients with diarrhoea
- Patients who are mentally disturbed or unconscious
- Patients who may have an added infection risk (most of the opportunistic organisms that cause infection in AIDS are not considered a risk to others; an exception would be Mycobacterium tuberculosis; patients with tuberculosis must be kept separate from HIV infected individuals)
Staff Management
- There is no vacciantinon to protect staff
- Antivirals are available to protect staff if they have a sharps injury with HIV infected blood
- Staff found to have HIV will, in general, not be allowed to perform invasive (exposure-prone) procedures
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