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HIV, the human immunodeficiency virus, is a virus which infects people for life and causes a severe clinical condition called AIDS. HIV infects cells of the immune system, particularly lymphocytes. HIV infection can be spread from one person to another.
HIV causes AIDS.
HIV infection is a relatively new condition which was first identified in Paris in 1983. Since then it has spread to almost every country in the world and by 2006 over 40 million people worldwide were infected. The number of HIV infected people dropped to 34 million in 2010. In 26 countries the prevalence of HIV decreased by 50% from 2001 to 2012.
In South Africa the prevalence in the age group 15 to 49 years has remained around 17% since 2008. According to the World Health Organisation (WHO) in 2010 South Africa had 260,000 HIV positive women who delivered 48,000 HIV infected infants due to perinatal mother to child transmission. The prevalence of HIV in pregnant women attending public health antenatal clinics in South Africa remained between 28 and 30% from 2004 through to 2011. The National Committee for Confidential Enquiries into Maternal Deaths (NCCEMD) reported 1360 maternal deaths due to AIDS for the triennium 2008 to 2010.
HIV probably appeared in humans in the 1950s. It was first transmitted to humans by chimpanzees in central Africa. From here it rapidly spread to all parts of the world, especially the USA, Europe, Asia and other parts of Africa.
Viruses are extremely small, very simple organisms which can only exist and multiply by invading and taking control of a plant or animal cell (the host cell). Viruses are responsible for many diseases. Unlike bacteria, they are not killed by antibiotics. Viruses may be divided into many different groups. HIV belongs to a group of viruses known as retroviruses.
They are a group of viruses which are unique in nature as they have a special enzyme which enables them to introduce their own genes into the nucleus of the host cell. The host cell is then instructed to produce millions of new copies of the virus. These copies are released into the bloodstream where they can infect other cells. Retroviruses usually cause long periods of silent infection before signs of disease appear.
HIV is a retrovirus.
AIDS stands for the Acquired Immune Deficiency Syndrome. This is a severe illness caused by advanced HIV infection and may present in many different ways. The symptoms and signs of AIDS are usually due to secondary infections with a number of different organisms. Some secondary infections are due to uncommon organisms not normally seen in HIV-negative people. AIDS is a slow, progressive, incurable disease which is fatal unless correctly treated with antiretroviral (ARV) drugs. AIDS was first recognised among homosexual males in the USA in 1981. The following year it was diagnosed in heterosexual men and women in Africa.
AIDS is a severe illness caused by HIV infection. There is a widespread epidemic of AIDS in Africa.
Most cases of AIDS occur in Africa. The spread of the HIV epidemic is greatest in southern Africa. It is estimated that six million adults and children have HIV infection in South Africa alone.
About six million South Africans are infected with HIV.
Yes. A person is usually infected with HIV for many years before developing symptoms and signs of the disease. Therefore, most people infected with HIV are clinically well and have a ‘silent’ or hidden infection.
The virus may be transmitted from one person to another by:
There is no evidence that HIV can be spread by mosquitoes, lice or bed bugs. In Africa, HIV is most commonly spread by heterosexual intercourse, especially when there are multiple sex partners.
In Africa, HIV is usually spread by sexual intercourse.
Yes. HIV is frequently transmitted by people who appear to be clinically well but are infected with HIV. This is the great danger of HIV infection as most infectious people do not know that they have been infected. They are also unaware that they may transmit HIV to another person.
By contact with infected body fluids which contain large amounts of HIV, such as:
The spread of HIV between adults by sexual intercourse is called horizontal transmission.
No. Family and friends of an HIV-infected person do not become infected except by sexual contact. HIV is not transmitted by close social contact such as touching, holding hands, hugging and social kissing. HIV is also not spread by coughing, sneezing, swimming pools, toilet seats, sharing cooking and eating utensils or by changing a nappy. However, any bleeding, such as nose bleeds, may spread HIV if the blood comes in contact with broken skin or mucosal surfaces.
In Africa HIV is almost always transmitted by penetrative sexual intercourse. However all forms of oral sexual contact (mouth to vagina or mouth to penis) can also result in infection, although the risk is less. Deep kissing may possibly transmit HIV, especially if mouth ulcers are present. HIV is not present in urine or stool while very little is present in saliva. HIV cannot penetrate intact skin but may infect open sores, cuts and abrasions, or mucous membranes. The thin, friable rectal mucosa is easily damaged during anal intercourse and, thereby, increases the risk of infection. Men who have been circumcised have a lower risk of being infected through sexual intercourse.
In comparison to other viral illnesses such as hepatitis B, HIV is not very infectious, and repeated exposure to large amounts of virus is usually needed for transmission. People with early and advanced HIV infection are most infectious. Other sexually transmitted diseases and abrasions of the vaginal and cervical epithelium increase the risk of infection. The highest risk of sexual transmission for both men and women is during anal intercourse. Patients on ARV treatment are less infectious.
Within weeks of becoming infected, when HIV levels in the blood are very high, promiscuous people with multiple partners may infect many people.
Usually a blood test is used to screen people for antibodies to HIV and HIV antigens (proteins). Antibodies are produced by the immune system to protect the body against invading organisms, such as viruses. Unfortunately they offer little protection to HIV. The presence of HIV antibodies in an adult, or child older than 18 months, indicates HIV infection.
A number of antibody tests are available to diagnose HIV infection.
Combined antibody antigen tests have become the standard laboratory test to detect HIV infection. It is a highly accurate test and is used to screen for HIV infection and for confirming a clinical suspicion of HIV infection. From the time of infection it takes between 14 to 21 days for the test to become positive. Two positive tests, using kits from two different manufacturers on the same blood sample, are needed before a definite diagnosis of HIV infection is made. This is done to make sure that an error has not been made. The antigen included in the combined tests is a HIV protein called the p24 antigen.
Rapid tests have been developed to detect HIV antibodies in blood, urine and saliva. The new generation of rapid tests detecting both antibodies and antigens are very accurate and in many places have replaced laboratory tests for screening and confirming HIV infection. Two rapid tests using kits from different manufacturers should be used to diagnose HIV infection. The great benefit of the rapid test is that it can be done on site to give same day results. If the rapid test is negative it is very unlikely that the person has HIV infection. Two positive rapid tests indicate HIV infection. If the first rapid test is positive but the second negative, blood must be taken for laboratory testing.
Two positive laboratory or rapid tests are needed to diagnose HIV infection.
Viral tests, which do not rely on HIV antibodies, can also be used to diagnose HIV infection:
A positive PCR test in an infant indicates that the infant is infected with HIV.
The antibody tests may be negative for 2 to 8 weeks and the combined antibody antigen laboratory or rapid screening tests may be negative for 14 to 21 days after infection with HIV. This is known as the window period. During the window period these people are still infectious to others, despite their test being negative. The window period for the PCR test is 11 to 12 days.
In response to infection with HIV, the immune system produces antibodies against the virus. Unfortunately these antibodies fail to kill all the HIV and cure the infection. At the time that HIV antibodies appear in the blood (seroconversion) some people develop a flu-like illness which lasts a few days or weeks. This illness starts two to four weeks after infection with HIV and is called acute seroconversion illness (or acute HIV syndrome). It only occurs in about half of HIV-infected individuals.
The usual signs of acute seroconversion illness are:
The above signs and symptoms are similar to those found in glandular fever (infectious mononucleosis).
During the first few weeks of HIV infection, large amounts of virus are present in the blood and the person is very infectious to others. HIV is most infectious during the acute seroconversion illness. HIV screening tests may still be negative at this time.
Acute seroconversion illness is often the first sign of HIV infection.
HIV infection, with or without acute seroconversion illness, is followed by months or years when the person feels well. In adults, this silent, asymptomatic period is usually five to ten years but may last for as long as 15 years before the signs of symptomatic HIV infection appear. In children, the latent phase is much shorter, from a few months to five years. Occasionally, asymptomatic HIV-infected adults may also progress rapidly to symptomatic HIV infection. Generalised lymphadenopathy is common in the latent phase.
HIV infection can, therefore, be divided into three phases:
Patients who have signs and symptoms due to HIV infection following the latent phase are said to have symptomatic HIV infection (HIV illness or HIV disease). Only when they become severely ill is the clinical condition called AIDS.
The clinical signs of symptomatic HIV infection are largely due to a wide range of infections and cancers, which occur because of the damaged immune system.
Common clinical signs in adults with symptomatic HIV infection are:
HIV infection often presents with weight loss and chronic diarrhoea.
The severity of HIV infection can be graded from 1 to 4 based on clinical symptoms and signs. Grade 4 infection is most severe and is called AIDS.
Opportunistic or HIV-associated infections are infections which usually do not occur in people with a normally functioning immune system. They are severe, repeated or chronic infections with common bacteria and viruses or infections with uncommon organisms. The organisms causing most opportunistic infections in HIV-positive people are:
Opportunistic infections are common in HIV-infected people due to their damaged immune systems.
An opportunistic infection, such as tuberculosis, is often the first sign that the patient is infected with HIV. Therefore HIV infection must be suspected and screened for in any person who has severe, chronic, repeated or unusual infections.
At present AIDS is a severe, chronic illness which cannot be cured and has a slowly progressive and fatal outcome without the correct management. However, treatment with ARV drugs can prevent the progression of the disease and improve the quality of life for many years. Without treatment, most AIDS patients will die within two years of the onset of the clinical illness. While the amount of virus in the body can be drastically reduced by ARV drugs, some virus unfortunately remains hidden in the lymphocytes. The aim of HIV management is to keep the person well for as long as possible.
HIV infection can be avoided by:
The ‘ABC’ of preventing HIV infection is Abstinence, Be faithful to one HIV-negative partner only, and use a Condom if there is any chance that the sexual partner may be HIV positive. Delaying the start of sexual activity and then reducing the number of sexual partners is most important. Having more than one sex partner at a time is dangerous. The only way the HIV epidemic will be controlled is by reducing the number of new infections by practising safe sex and by preventing perinatal mother to child transmission of HIV.
Every effort must be made to reduce the number of new HIV infections.
Yes. The presence of other sexually transmitted diseases increases the risk of HIV infection, especially if these other diseases cause ulcers or mucosal damage. Treatment of these sexually transmitted diseases reduces the risk of the sexual spread of HIV.
Important examples are:
The risk of HIV infection is highest if ulcers are present, as in syphilis, chancroid and herpes.
Yes, although the risk of infection varies widely between individuals. HIV is most infectious in the first weeks of the infection and again in seriously ill people when the signs of AIDS develop. At these times there are large amounts of HIV in the blood (a high viral load). The risk of infection is less during the latent period when smaller amounts of HIV are present in the blood. However, most HIV is still spread during the latent period when many people are unaware that they are infected. It is therefore very important that all sexually active adults know their HIV status.
Patients with a high viral load are most infectious.
No. During heterosexual intercourse HIV is more infectious to women than to men as HIV-infected semen may remain in the vagina for many hours. Therefore, in most countries where sexual transmission is common, HIV infection is more frequent in women. In South Africa during 2008 to 2011 the adult prevalence of HIV infection in the age group 15 to 24 years ranged between 12 and 13% for females and 5 and 6% for males.
HIV invades and destroys the immune system by damaging the CD4 lymphocytes. These special cells are produced by the thymus and control the functions of the immune system. CD4 lymphocytes are also called helper lymphocytes as they assist other types of lymphocytes. A normally functioning immune system prevents severe infections and the development of malignancies. HIV infection causes a fall in the number of CD4 lymphocytes with the result that the immune system cannot function normally. As a result, the risk of infection and cancer increases.
The CD4 count is a very important way of determining the immunological stage of the HIV infection, by measuring the amount of damage that has been done to the immune system.
The body also responds by producing antibodies to the HIV. Unfortunately, the antibodies cannot kill all the virus, which is able to hide inside cells.
HIV damages the immune system by attacking and destroying the CD4 lymphocytes.
HIV is a retrovirus which infects human CD4 lymphocytes. Retroviruses invade the nucleus of lymphocytes and instruct these ‘host’ cells to produce more copies of the virus. HIV therefore ‘hijacks’ the host cell and converts it into a factory which produces millions of new viruses. Antiretroviral drugs act by stopping the multiplication of HIV in lymphocytes.
There are a number of drugs which can reduce the amount of HIV in the body and, thereby, slow the progression to AIDS, or improve the clinical signs of AIDS. At present none of these drugs can cure AIDS. They are called antiretroviral (ARV) drugs. It is best to use at least three of these drugs together. Combination therapy is more effective and helps to avoid drug resistance.
There are four groups of ARV drugs. They block the function of enzymes needed for the multiplication of HIV.
ARV drugs can be used to treat a patient with severe HIV infection (ARV treatment) or to prevent infection with HIV (ARV prophylaxis). TDF, FTC and EFV (Odimune, Tribuss, Atroiza and Atripla) as a single pill fixed dose combination (FDC) regimen are most commonly used to treat and prevent perinatal mother to child transmission (PMTCT) of HIV. AZT and NVP are the commonest drugs used for HIV prophylaxis during labour if patients received no ARVs antenatally. NVP syrup is given to infants postpartum and during breast feeding to prevent infection.
Zidovudine (also called AZT) was the first ARV drug available. It is effective when used prophylactically during pregnancy and labour to reduce the risk of transmission of HIV from mother to infant. It can also be given to the newborn infant after delivery. When used alone for a short period it is uncommon for HIV to become resistant to AZT.
AZT is well absorbed orally and crosses the placenta well. It increases the fetus’s ability to resist infection from HIV. AZT needs to be taken twice a day.
3TC, TNF and FTC are commonly used and has the same mechanism of action as AZT. Common side effects of these drugs are shown in table 1-1.
|AZT||3TC and FTC||TNF|
|Headache||Headache||Vomiting and diarrhoea|
|Malaise (feeling tired)||Nausea||Peripheral neuropathy|
|Nausea and vomiting||Pancreatitis||Lipodystrophy|
|Bone marrow suppression resulting in anaemia and neutropenia||Skin hyperpigmentation||Lactic acidosis|
NVP is a potent and rapidly acting antiretroviral drug, which is very useful in reducing the risk of HIV transmission from mother to infant during labour and delivery. It is absorbed orally and crosses the placenta very well. A single dose is given to the mothers newly diagnosed to be HIV positive during labour or if ARV treatment has not yet been started. NVP has few adverse effects when used as a single dose. However, resistance develops rapidly when NVP is used as a single dose. Therefore, NVP always is used with Truvada (a combination of TDF and FTC) to prevent resistance developing.
Prophylactic NVP is very useful in reducing the risk of mother-to-child transmission during labour and delivery for newly diagnosed mothers who are not yet on antiretroviral treatment.
EFV is also a non-nucleoside reverse transcriptase inhibitor and commonly used together with TDF and FTC as a single FDC tablet taken once daily. EFV is also used with AZT and 3TC as HAART when there are contra-indications to the use of TDF.
Common side effects of these drugs are shown in table 1-2.
|Skin rash, that could be severe and life threatening (Stevens Johnson syndrome)||Dizziness/drowsiness|
|Hepatoxicity (liver damage) that could be severe and life threatening||Insomnia (unable to sleep)|
|Possible fetal harm during the 1st trimester|
¹Side effects do not occur if used as a single dose
²Frequency of these side effects much lower compared with NVP
Unfortunately not. An effective vaccine against HIV is the only way that the HIV epidemic will be controlled. Many studies are being conducted in an attempt to produce an HIV vaccine. However it may be many years before an effective HIV vaccine is available.
The general management of adults with HIV infection consists of the following:
Except for the use of ARV drugs, the general management of HIV infection is not expensive and makes a big difference to the quality of the patient’s life. Whenever possible, the patient should not be admitted to hospital, but managed at home with the support of the community and primary healthcare services. Patients with AIDS should never be abandoned. AIDS cannot be effectively treated with diet alone.
Yes, as body fluids, especially vaginal discharge and cervical secretions, blood, amniotic fluid, breast milk and semen may contain large amounts of HIV. Healthcare workers can become infected by HIV via the following routes:
By adopting standard (universal) precautions. This means that all body fluids should be regarded as potentially infectious in all patients. Precautions should always be taken to prevent exposure to infectious body fluids.
All patients should be regarded as being potentially HIV positive. Therefore, general precautions should be taken with all patients. These precautions are especially important in patients known to be HIV positive.
Standard precautions should be adopted when managing all patients.
Always use a sharps container for the disposal of lancets or needles.
The overall risk without antiretroviral prophylaxis is 1 in 300. Therefore, of every 300 healthcare workers who prick or cut themselves with an instrument covered with HIV-positive blood, one person will become infected with HIV. With the correct use of antiretroviral prophylaxis this risk is reduced by 80%. The risk of infection is greatest if:
The risk of infection without antiretroviral prophylaxis after a splash of HIV-infected blood into the mouth or eye, or contamination of a cut or skin abrasion, is less than 1 in 1000.
Healthcare workers may be accidentally exposed to HIV by needle-stick injuries or splashes of infected body fluid into the eyes or mouth, or onto broken skin. The risk of infection is greatest with a cut or needle-stick injury. Every effort must be made to start antiretroviral prophylaxis within two hours of exposure. Start treatment as soon as possible. Treatment is probably not effective if the delay is greater than 72 hours.
Prophylaxis is strongly recommended with mucosal splashes if the patient is sick with AIDS. Prophylaxis is not indicated after exposure to uncontaminated, non-infectious body fluids.
One tablet of Truvada and one tablet of lopinavir/ritonavir (Aluvia) should be taken immediately and then continued for 28 days for prophylaxis. One tablet of Truvada contains TDF 300 mg and FTC 200 mg and is taken once daily. Aluvia contains lopinavir 400 mg and ritonavir 100mg and is taken 12-hourly. The adverse effects of nausea, vomiting, diarrhoea and tiredness are common. Therefore both drugs are best taken with food and an anti-emetic can be taken a half an hour before taking the tablets to reduce nausea.
Always acquaint yourself with the local post-exposure prophylaxis (PEP) protocol.
After a needle-stick injury the following procedure should be followed:
All hospitals and clinics must keep emergency packs of prophylactic antiretrovirals for staff with accidental exposure to HIV.
During a public lecture at a social club, the speaker says that HIV infection in Africa is usually acquired by heterosexual intercourse. He also says that HIV infection is commoner in women. During question time a member of the public asks whether HIV is also spread by kissing. Another member of the audience asks if HIV infection is the same as having AIDS, and whether people who are HIV positive but well can be infectious to others.
Yes. Heterosexual intercourse is the most common method of spreading HIV in Africa. However, the vertical spread from mother to infant is also very important. Homosexual intercourse and the use of contaminated needles are other important methods of spread in some communities.
Because HIV is usually spread by unprotected heterosexual intercourse. As semen may remain in the vagina for some time after intercourse, women have a greater chance than men of being infected.
Probably not. HIV cannot be acquired by non-sexual contact such as social kissing, holding hands, hugging and sharing cooking and eating utensils.
No. The difference commonly causes confusion among members of the public. Most people with HIV infection remain well for years before they become seriously sick with the illness called AIDS. Therefore, it is very common to have HIV infection without AIDS. With time, however, these people with asymptomatic HIV infection will become sick.
Yes. Everyone with HIV infection is infectious to others even if they are clinically well. Patients on ARV treatment are less infectious than patients not receiving treatment.
A blood donor has a routine HIV test which is negative. A few weeks later she has unprotected sexual intercourse with a stranger she met in a night club. After three weeks she develops a fever, a mild cough and a generalised pink rash. On examination, her doctor notes that she has enlarged lymph nodes in her neck and axilla, and small ulcers on her throat. He diagnoses infectious mononucleosis and prescribes oral penicillin. She recovers rapidly. Six months later, when she again asks to donate blood, it is found that she is HIV positive.
Acute seroconversion illness. This occurs two to four weeks after HIV infection in about 50% of individuals. It is often misdiagnosed as acute infectious mononucleosis (glandular fever) as both conditions present with fever, sore throat, rash and lymphadenopathy.
By abstaining from sexual intercourse or by using a condom.
No. There is no risk in donating blood provided that a sterile needle is used. However, one can become infected by receiving blood donated by someone who is infected with HIV. Therefore, all donated blood in South Africa is screened for HIV.
She will probably remain well for five to ten years. However, the latent phase of HIV infection may last as long as 15 years.
A young man presents with shortness of breath and a chronic cough. During the past few months he has noticed an unexplained weight loss. On examination he has oral thrush and generalised lymphadenopathy. A chest X-ray shows pneumonia with a cavity in one lung. The HIV rapid test is positive. Recently he was treated for syphilis.
Symptomatic HIV infection complicated by tuberculosis (TB). HIV infection commonly presents with a history of weight loss, cough and shortness of breath.
Yes. It may be the first sign that the patient has symptomatic HIV disease.
Thrush is an infection caused by the fungus Candida. It is common in young infants but rare in adults. Thrush is one of the opportunistic infections which complicate HIV infection.
Because HIV damages the CD4 lymphocytes which play an important role in the immune system. Thrush, therefore, takes this opportunity of infecting the mouth. Some opportunistic infections, such as Pneumocystis and CMV, may also cause pneumonia which often presents with cough and shortness of breath.
Often more than one sexually transmitted disease occurs in a patient. Syphilis causes genital ulcers that increase the risk of HIV infecting the person.
AIDS can be treated with a combination of ARV drugs. While the signs and symptoms of AIDS may disappear while on treatment, HIV infection cannot be cured. A vaccine holds the only hope of ending the HIV epidemic.
After collecting capillary blood for glucose measurement from the heel of a newborn infant, a nurse accidentally pricks her finger with the lancet while cleaning up. A sharps container is not available in the nursery. She only informs the management the following day. Blood from the patient and the nurse is then sent urgently to the laboratory and the HIV test on the patient is positive. A one month course of Truvada and Aluvia is started but she stops after a week as the medication makes her feel nauseous and tired.
There was no sharps container in the nursery. After collecting a blood sample, the needle or lancet must immediately be placed in a special sharps container. It is extremely dangerous to place the used needle or lancet on the bed or work top, as staff commonly prick themselves while tidying up afterwards.
Immediately. As soon as any staff member pricks him- or herself with a blood-stained needle or lancet, the management must be informed so that the procedure of testing the patient’s blood and starting prophylactic ARV drugs can begin without delay. Every hospital and clinic must have a clear list of instructions as to the correct procedure after a needle-stick injury.
Yes. A course of both Truvada and Aluvia are used for needle-stick injuries. However, the risk of HIV infection is increased if the treatment is not started within a few hours of the needle-stick injury.
Without treatment the risk is about 1 in 300. This risk is greatly reduced if the correct prophylactic treatment is started as soon as possible, preferably within two hours.
Yes. To be as effective as possible the treatment must be taken for 28 days.Unfortunately the ARV agents do have adverse effects such as lethargy and nausea. As a result the full course of treatment is often not taken. Counseling regarding side effects of the drugs and measures to reduce side effects must always be given.