HIV (human immunodeficiency virus) is the causative virus of AIDS (acquired immune deficiency syndrome). AIDS has no precedent in medical history. It was first widely recognized in 1981, although evidence of the virus was found in stored blood collected in 1959, and so it seems that it has been in existence for longer than was first thought. The virus primarily attacks the white blood cells (the T-lymphocytes or CD-4 cells) and macrophages of the body. These cells play a key role in maintaining a person's immunity to disease. As a result, HIV infected people become susceptible to illnesses caused by the collapse of the body's immune system. Individuals infected with the virus are infectious for the rest of their lives, and can transmit HIV via blood or sexual fluids.
The common conditions and diseases related to AIDS include Kaposi's sarcoma (cancer of the lining of the blood vessels), pneumonia, tuberculosis, toxoplasmosis (viral infection affecting the central nervous system), cytomegalovirus (CMV) infection (a common viral infection that can ause retinitis and blindness), candidiasis, and severe herpes. As the depressed immune system makes the individual vulnerable to many illnesses, almost any symptom may occur in HIV infection.
Stages of infection
First 12 weeks
Some people develop an illness resembling an acute glandular fever-like illness within 6 weeks of infection. Symptoms include fever, headache, swollen glands, tiredness, aching joints and muscles, and a sore throat. However, most people will not feel unwell or develop any abnormality for years. Antibodies to HIV usually develop within 2 to 8 weeks, and almost always by 12 weeks. The 12 weeks after initial infection is called the "window period", where a negative test does not necessarily indicate that a person is free of the virus and a follow-up test will be necessary. However, by the end of the window period virtually all infected people will have a positive blood test (i.e. they will test "seropositive" or "HIV-positive"). Developing an HIV-positive test is known as "seroconversion".
HIV-infected individuals can remain physically well for many years after initial infection. However, in general the virus slowly attacks the immune system and, at a critical point, the condition AIDS develops.
Within 5 years of infection, up to 30% of those individuals infected with HIV are likely to develop AIDS (i.e. severe conditions such as cancer and pneumonia). A proportion of people will develop less severe symptoms, such as persistent generalised lymphadenopathy (swollen glands), diarrhoea, fever, and weight loss. Studies indicate that about 50% of adults infected with the virus will develop AIDS within 10 years of infection.
Of individuals diagnosed as having AIDS, 90% are likely to die within 2 years if not treated. Antiretroviral therapy with zidovudine (also known as AZT or Retrovir), which can reduce mortality, illness, and the numbers of opportunistic infections, is available to people with diagnosed AIDS. Newer drugs such as ddI, ddC and other antiretroviral agents are being introduced all the time. However, the avoidance of infections, the prompt treatment of infections, and a generally healthy lifestyle with exercise and good nutrition may substantially reduce the likelihood that an HIV-infected individual will develop AIDS.
Transmission How it is spread
HIV is transmitted only through the exchange of infected body fluids, whereby a substantial quantity of virus gains access to the T4 cells in a susceptible individual. Although the virus occurs in saliva, tears, cerebrospinal fluid, and urine, these fluids do not pose a significant risk because of the low concentration of the virus and the absence of a common mechanism for them to enter the blood of another person.
HIV occurs in relatively high concentrations in the blood, semen, and vaginal and cervical secretions of infected individuals. Therefore, there is a significant risk of infection when these body fluids are passed directly into another person's blood or anal or genital tract. HIV is also present in breast milk, which is a possible vehicle of transmission to infants.
There are only three significant routes of transmission for HIV:
- from infected blood or blood products
- from infected sexual fluids
- from infected mother to baby during pregnancy and delivery (if a pregnant woman is HIV-positive, the baby has a one in 3 chance of being infected).
How it is not spread
There is no risk of infection through social non-sexual contact such as kissing, sharing utensils (e.g. cups), body contact, or the use of public toilets. HIV is not spread by mosquitoes or other insects.
Since April 1985 therapeutic blood products have been made safe in Australia by excluding high risk donors and screening donated blood. Each donor must sign a declaration stating that she or he does not have any high risk factors for HIV. This system has largely prevented the donation of blood by HIV-positive people in South Australia. Thus, blood transfusions given before 1980 and after April 1985 are not a risk for HIV infection in Australia.
Unsterilised equipment used for tattooing and acupuncture could transmit the infection, but this source is unlikely in South Australia. It is possible for the virus to be transmitted through needle-stick injuries to health workers, and also during unsafe disposal of needles and syringes. Fewer than 30 health care workers in the world are reputed to have been infected in this way, but the high incidence of needle-stick injuries reported indicates a need for continuing the precautionary guidelines.
Blood transmission of HIV is virtually confined to needle and syringe sharing among injecting drug users. Anyone who shares a needle or syringe with an infected person is at high risk of contracting HIV because there are large quantities of the virus in blood, which is then injected directly into the bloodstream.
Exact levels of risk for the various forms of sexual activity are not known, but some sexual practices have higher risks associated with them than others.
Transmission can occur in either direction during unprotected vaginal intercourse. The risk of infection is greater for the woman - the risk of infection passing from men to women during vaginal intercourse is two to three times greater than the risk of it passing from women to men. HIV can be absorbed into the woman's bloodstream during unprotected vaginal intercourse via tears in the vaginal wall, genital ulceration, an inflamed or traumatised cervix caused by cervicitis, or by absorption through the membrane of the cervical canal. Also, because semen remains in the vagina and around the cervix after intercourse, the risk of transmission is increased. Until 1987, only 3% of American men who died of AIDS had contracted the disease through heterosexual intercourse, whereas 27% of infected women had contracted it in this way (McEgan, 1987).
Transmission can occur in either direction, but the receptive partner is at greater risk. Anal intercourse without a condom is the highest risk sexual activity because the rectal lining is fragile and prone to tearing, thus allowing easy access for infected blood and semen. One San Franciscan study found that a person who has unprotected anal intercourse is two-and-a-half times more likely to contract HIV than a person who does not.
The risks of oral sex are unclear. Cuts, infections in the mouth or throat, and gingivitis (infected gums) could pose some risk. Clinic 275 advises that it is difficult to ascertain the safety of oral sex and advises people not to allow semen to be ejaculated into the mouth. The fluid expressed from the urethra before ejaculation is also likely to be infectious. Similarly, menstrual blood contains high concentrations of the virus and should also be avoided.
Clinic 275 suggests that oral sex is relatively safe if ejaculation of potentially infected semen into the mouth is avoided. They also recommend the avoidance of teeth cleaning and dental flossing before oral sex.
Mutual masturbation and other forms of non-penetrative sexual activity are safe provided that blood or sexual fluids do not enter a partner's body.
When there is genital ulceration in either partner, or when an uninfected male partner is uncircumcised, the risk of transmission probably increases.
Approximately 30% of infants born to untreated HIV-positive women are infected. It is not known at what stage of the pregnancy the foetus is infected, but recent evidence supports the notion that the infant often becomes infected during the birth process. Further research is being done in this area.
Statistics Global perspective
The first cases of AIDS were reported in the USA in 1981, when young, homosexual men were diagnosed with Kaposi's sarcoma, an unusual disease among young people. It is now estimated that several million people are infected with HIV world-wide (see Statistics Section for details). However, because of the differing abilities of affluent nations and poor nations not only to respond to the epidemic, but also to keep track of cases, current estimates may not be accurate and do not reflect the potential impact on different countries. The largest pool of infection is in Africa, where transmission predominantly occurs through heterosexual contact and infected blood given in transfusions (10% of infections - usually there are no blood-screening programs). Two-thirds of the estimated global total of AIDS cases, and the majority of HIV-positive people, are in this region. There is now the potential for rapid spread of HIV through Asia and India.
The World Health Organisation (1991) estimated that the distribution of HIV infection in the world is as follows:
- 60% in sub-Saharan Africa
- 30% in North America and Australia
- 6% in Europe
- 4% in Asia and the Middle East
In addition, the socio-economic conditions and levels of prostitution in some developing countries (e.g. Thailand) are conducive to rapid spread of infection.
WHO estimates that HIV is spread in the following way:
- 60% transmitted through vaginal intercourse
- 15% through anal intercourse
- 10% through injecting drug use
- 10% perinatally (i.e. from mother to baby in the uterus or during the birth process)
- 5% through contaminated blood and other injections
The first cases of AIDS in Australia were diagnosed in 1982. HIV and AIDS are most common in the eastern states, particularly in Sydney, and are generally concentrated in urban areas. Transmission is mainly through unprotected male-to-male anal intercourse and needle or syringe sharing among injecting drug users.
One Australian study of risk factors for HIV has been undertaken by Ross (1988). He found that the proportions of individuals, both male and female, who had had homosexual or sex worker contact were much lower than those expected (based upon levels found by Kinsey et al in the 1950s). Levels of injecting drug use were found to be highest among the 15-24 year age-group, with higher levels among males than females. Estimated numbers of injecting drug users vary from 20,000 (Australian Royal Commission of Inquiry into Drugs, 1980) to hundreds of thousands of users in different categories of use (Drew & Taylor, 1988). Nevertheless, the size and nature of the injecting drug user population are very different in Australia compared to the USA. The numbers are proportionately much smaller, and there is not the same representation of people from extremely disadvantaged backgrounds. Thus the potential for spread among heterosexuals is not as great as it is in the USA.
Infection levels among women who work as sex workers in Australia are low and should remain low among those who do not inject drugs.
See Statistics page http://www.stdservices.on.net/stats/default.htm for South Australian details, and The National Centre for HIV Epidemiology and Clinical Research http://www.med.unsw.edu.au/nchecr for Australian data.
Testing and counselling
The HIV antibody test is the blood test that determines whether an individual has HIV antibodies. A positive test means that there are antibodies and that HIV has established itself in the body. As previously described, it can take as long as 3 months - the window period - for antibodies to be produced. A negative test can mean that either HIV is not present in the body, or that the body has not had sufficient time to respond to the virus by producing antibodies.
It is important that people seeking testing have an opportunity to explore the issues that may confront them with either a positive or negative test result. Issues may include guarantees of confidentiality, the need for support, explanation of the test, personal issues (e.g. in relation to partners, insurance, safe sex practices, and safe drug use).
Informed consent should be obtained for all medical tests, and must be obtained before a HIV test is undertaken. Testing without consent constitutes an assault (unless authorised by the law). The person needs to be fully aware of the meaning of the test and its results, the procedures, and potential consequences. Consent obtained by deceit, withholding information, or giving misleading information does not constitute informed consent.
It is important that test results are given face-to-face by a medical practitioner or counsellor. The main aim of post-test counselling is to ensure that the person understands the implications and meaning of the results, and that follow-up is offered in the form of further appointments or referral. Results should not be given by telephone.
Implications of a negative test
A negative test result can provide reassurance and an opportunity to discuss prevention through safe sex and safe drug use. It is important to be aware that if exposure occurred less than 3 months ago a repeat test will be necessary.
Implications of a positive test
Since reactions to the diagnosis of HIV infection varies, it is important that the individual has access to counselling and support from a person (counsellor, nurse or doctor) experienced in HIV/AIDS issues. The doctor needs to check if there is a trusted support person available, to discuss medical follow-up and treatments, provide assurance of confidentiality, encourage notification of past and present sexual partners, support lifestyle changes, arrange referral to other support agencies where necessary, and arrange another appointment for further counselling. When first confronted with a positive test result, people frequently may not absorb much of the information they are given and follow-up appointments are important.
The following needs to be taken into consideration by the counsellor and the individual diagnosed with HIV infection:
the infection can be transmitted to others, and thus there is a need for lifestyle changes, social stigmatisation of people with HIV infection and irrational, fear-based responses of others make it even more difficult to come to terms with the infection.
AIDS combines several areas that are subject to enormous taboos and heavy social conditioning in our society, namely:
- sexual behaviour and sexuality (and often homosexuality);
- injecting drug use;
Individual reactions to a positive test result may depend upon a number of factors such as: Gay men Reactions differ, depending on whether the individual:
- identifies with the gay community or has an unrevealed association with men;
engages in sexual activity, involving male and female partners.
Blood or blood-product recipients Some wish to distance themselves as "innocent victims". People who inject drugs Reactions differ, depending on whether:
- the use is casual and under control or an addiction problem;
- the person wishes to continue drug use, placing the emphasis on non-sharing;
the person wants to discontinue use, placing the emphasis on social supports.
Sex industry workers Reactions differ, depending on whether the person:
- is a female or male sex worker;
- injects drugs;
- identifies with the prostitute community or acts independently;
perceives a potentially positive role for herself or himself as an educator in safe sex for clients.
Women Reactions differ, depending on:
- socio-economic status;
- whether or not a woman has children or is pregnant.
Interpersonal relationships Will infection destroy an existing relationship, or hinder new ones?
What kinds of support does the person have?
There may be guilt or hostility relating to who infected whom.
Does infection disclose unrevealed sexual relationships, sexual orientation, or injecting drug use?
Likely response of lovers, family, friends. Pre-existing psychological or intellectual problems Infection may exacerbate the existing condition.
Intellectual disability may make the spread of infection more difficult to prevent or increase the risk of unplanned pregnancy and transmission to the baby. Knowledge and preparation for a possible positive result
Studies show that the less knowledge and preparation an individual has, the greater the impact of the result will be.
This underlines the importance of pre-test counselling.
The most common initial reactions are extreme - severe shock which may temporarily immobilise the individual, or an apparently casual acceptance. The individual may deny the reality of the result for several days, weeks, or longer. Issues, such as relationship difficulties, self-blame, loss of self-esteem and/or loss of sexual libido may start to arise later. There are, of course, similarities between coming to terms with HIV and the process people go through when diagnosed with other fatal diseases. The difference is that HIV can result in rejection by friends, family, and health workers, and therefore social isolation. Thus, people often hide their diagnosis. It is important that individuals are informed of self-help and other groups available for HIV positive people.
Information about one person should not be disclosed to another, except in the following circumstances:
- Where another person has a need to know (e.g. a health service provider) - but it is essential to have the client's consent in all situations.
Where required by law (e.g. notifiable diseases).
HIV-positive people may need to be counselled about whom they wish to tell
- many breaches of confidentiality occur when individuals unwisely tell acquaintances, or leave identifying client documents around.
Health workers can use a range of strategies to protect confidentiality (e.g. contacting clients only by a mechanism they have approved).
Advantages of testing
- Access to appropriate treatments for HIV-positive individuals early in the infection can delay the onset of AIDS and prolong survival.
The detection of infection at an asymptomatic stage may avoid a range of severe physical and social complications that may occur when infection is detected in an emergency situation (e.g. an accident, in a hospital emergency room, or after admission to hospital with advanced disease). Breaches of confidentiality and privacy are more likely in these late stages, and there may not be sufficient time for the individual to benefit from treatments, come to terms with the illness, make any necessary practical living arrangements, or prevent the further spread of infection.
- A negative test result can relieve anxiety after perceived exposure to infection.
- A positive result can encourage the practice of safe sex and safe drug use, preventing the spread of infection as well as protecting the infected person from other STDs, or different strains of HIV.
- Widespread testing helps to determine the extent and distribution of infection, which in turn can assist in planning support and prevention strategies.
- A positive result may affect a person's important life decisions, for example, about whether or not to have children.
- Individuals may make other lifestyle changes that improve their health status and life expectancy.
People have the right to make their own choices about undergoing a test. If an individual chooses not to be tested, it is important that he or she practises safe sex and injects drugs safely to protect themselves as well as others. Individuals may not wish to be tested because they have never been offered pre-test counselling. Similarly, a more balanced community perception of HIV infection could help individuals feel less hesitant. Confidentiality should ensure that other people know an individual's status only if he or she tells them, and it is important that people who fear a breakdown in confidentiality are assured of this. People with positive test results need to be selective about whom they tell. Discrimination on the grounds of HIV infection is covered by anti-discrimination legislation, and is against the law, although it can be difficult to prove. Insurance companies will require a test before underwriting a substantial policy.
From a public health perspective, all individuals at risk of HIV should be encouraged to have an HIV test.
Four blood tests are available:
- Enzyme immuno-assay; Enzyme linked immunosorbent assay (EIA; ELISA)
- Western blot (WB)
- Immunofluorescent assay (IFA)
- Radio-immunoprecipitation assay (RIPA)
The most common approach is the use of an EIA test for screening (the initial test) and a western blot for confirmation. It usually takes 7 days for the results to be ready.
There are a wide range of medications that will slow the progression of HIV infection:
Antiretroviral therapy - zidovudine (Retrovir or AZT) is the most widely used and reduces mortality, illness, and the number of opportunistic infections when given in combination with other agents such as ddI or ddC. In Australia, anti-HIV medications are available to people in the following circumstances:
- A person with a T4 count less than 500;
- Anyone with an AIDS-related condition;
- Someone with needle-stick injuries from a known HIV-positive person.
The side-effects of zidovudine treatment can include anaemia, vomiting, insomnia, and myalgia (muscle pain). However, these side-effects are more common on high-dose regimes. The new low-dose regimes have fewer side-effects.
Side-effects of ddI and ddC include inflammation of the pancreas and damage to nerves.
Many new anti-HIV drugs have recently been introduced in Australia. More information about these medications is available on the HIV management http://www.stdservices.on.net/std/hiv-aids/management.htmpage in the Diagnosis and Management section http://www.stdservices.on.net/management/default.htmfor doctors.
Many of the opportunistic infections that occur with AIDS can be treated with medications such as antibiotics, anti viral drugs (aciclovir), and anti malarial medications.
Legal and ethical issues
In South Australia, HIV infection is a notifiable disease, which means that medical practitioners are required by law to notify the HIV Epidemiologist in the Public and Environmental Health Service of the South Australian Health Commission.
Laws cover donor activities, including blood transfusion.
Anti-discrimination laws apply to employment, accommodation, education, and the provision of goods and services. The law applies to any physical impairment, and probably includes asymptomatic HIV infection.
Prevention The Australian Federation of AIDS Organisations (AFAO) has defined safe sex in the following way:
Safe sex is any form of sex in which HIV does not pass from the blood, semen, or vaginal fluids of one person directly into the bloodstream of another person. (AFAO, 1991)
This definition is specific to HIV/AIDS and does not attempt to deal with other STDs.
There is more information about safe sex available at the Safe Sex and Condoms page http://www.stdservices.on.net/std/prevention/Default.htm.
In addition to providing general support, it is also important to support HIV-positive people in preventing the spread of infection. Counselling on safe sex practices so that individuals are clear about what is and what is not safe, is imperative. Education about clean needle and syringe use is important for people who choose to continue injecting drugs. People should be referred to needle exchange programs.
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