HIV AND AIDS

What Are HIV And AIDS? HIV, or human immunodeficiency virus, was first isolated by scientists in 1983. A year later it was proven that HIV was a cause of AIDS (acquired immunodeficiency syndrome). There are currently two known forms of HIV, HIV-1 and HIV-2. Both viruses are "retroviruses", which means that they are RNA viruses, but use a special enzyme known as reverse transcriptase (which copies RNA into DNA) in one stage of their replication. HIV-1 is the more common cause of HIV infection throughout the world, while HIV-2 is mainly found in a number of West African countries. Both these viruses have the same modes of transmission and are associated with similar signs and symptoms; however, they vary slightly in their course of illness and infectiousness. AIDS is the most severe manifestation of a wide range of HIV-related conditions which vary from minor to life-threatening, depending on the stage of illness. If a person is infected with HIV, it does not necessarily mean they have AIDS. However, in the overwhelming majority of patients, the development of AIDS from an HIV infection is inevitable. AIDS is a disease in which the body's immune system, a system which is designed to protect us from infections and other conditions, no longer works effectively. This makes people who are immunodeficient very vulnerable to illnesses that would not normally occur in people with an intact immune system. These illnesses are called opportunistic infections and will be discussed below.

How Does One Get Infected With HIV? Although HIV infection is an incurable and fatal illness, it is entirely preventable. HIV is only acquired through the exchange of blood, semen, and vaginal secretions with a person who is infected with HIV. This occurs when there is unprotected sexual intercourse, sharing of contaminated needles, receiving a blood transfusion infected with the virus, or from an HIV-infected mother to her newborn child. Unprotected sexual intercourse can mean vaginal, anal and oral sex, and occurs when there is incorrect or inconsistent use of a condom. The use of oral contraceptives, spermicide and diaphragms do NOT protect you from the virus. It is thought that during unprotected sex, the virus can enter the body through cuts or sores in the vagina, penis, rectum and even mouth. Since many infected people do not have any apparent symptoms early on in their illness, it is difficult to know who is infected and who is not. Therefore, the more sex partners you have the greater your risk of becoming infected with HIV. Sharing contaminated needles, which include reused needles to inject drugs and those used for tattoos and ear piercing, put you at risk for HIV infection. If it has been used previously by an HIV-infected person, blood which may not be visible can remain in a needle, and the virus can thus be transferred directly into your blood stream. Although acquiring HIV through a blood transfusion is a well known concern, the risk of becoming infected has been reduced to almost zero with the introduction of screening all blood for HIV. What may be less well known is the transmission of HIV from an infected mother to her newborn child during pregnancy, through the process of childbirth and even breast feeding. Research has indicated that the child has approximately a 25% chance of becoming infected if no safety precautions are taken. Taking anti-retroviral drugs such as Retrovir (azothymidine) can reduce your child's risk by more than a half. Please contact your doctor if you are pregnant and suspect that you are infected.

What Are Some Things That Do Not Put One At Risk For HIV Infection? It is important to know when you are NOT at risk of becoming infected with HIV. There is no known evidence that HIV can be transmitted by saliva, tears, sweat, sneezes, urine or through touch. Thus, you are not at risk for HIV infection by everyday contact with HIV-infected patients. This includes using sharing telephones, toilets, utensils, cups, and spoons that has been used by a patient infected with HIV. Although small amounts of the virus have been detected in saliva, there is a special protein in saliva that effectively kills the virus. Thus, there have been no known cases of acquiring HIV through kissing. However, scientists do advise people to avoid deep kisses. There is no evidence that HIV is spread by mosquitoes, as happens for other diseases such as malaria.

What Are The Signs And Symptoms Of HIV Infection? Within one to four weeks after someone is first infected, there is a period in which the body mounts an immune response to the virus, which has, by this time, replicated thousands of times. This reaction is called the "primary HIV infection" and is characterized by a general sense of feeling unwell, with fever, skin rash, pain in the joints, and swelling of the lymph nodes. These symptoms can last anywhere from three to fourteen days. This primary infection is often incorrectly believed to be either the flu or mononucleosis. These symptoms will disappear and the patient will be asymptomatic, with no outward symptoms of infection. However, there will be antibodies to the virus in the person's blood. Antibodies are special proteins produced by the body to fight against invading organisms such as the HIV virus. This is a dangerous period, with respect to transmitting the virus, since the person is infectious but may not know that he/she is. This asymptomatic period, on average, lasts about ten years. After this time, many individuals begin to experience the early symptoms of the disease. These include the development of oral lesions, such as thrush, hairy leukoplakia and painful ulcers. Thrush is due to the fungus Candida and occurs commonly on the gums and soft palate, while hairy leukoplakia occurs on the side of the tongue and is caused by the Epstein Barr virus. Both these infections occur because the patient's immune system has been so severely weakened by HIV that it cannot fend off the responsible agents, which are present in everyone. There are numerous other early signs, such as shingles and thrombocytopenia (a low number of platelets in the blood - platelets are involved in blood coagulation), which also occur at this time; however, to discuss all of them is beyond the scope of this article. Patients with HIV can also experience neurological problems that are a result of either an infection or the growth of a tumor. Both causes are related to their immunodeficient status. Some of the more common neurological conditions include HIV encephalopathy (also known as AIDS-related dementia), toxoplasmosis infection and cryptococcal meningitis. All of these conditions can produce seizures as the disease progresses. In the late stages of HIV, opportunistic infections are common. In fact, opportunistic infections are the leading cause of death in HIV patients. These opportunistic infections include pneumonia resulting from bacterial and protozoal infections, a form of skin cancer called Kaposi's sarcoma, tuberculosis and cryptococcal meningitis, a fungal infection of the nervous system.

What Are The Main Laboratory Tests For Infection with HIV? Tests to measure antibodies present in plasma to HIV are widely available. Another type of widely used test is the measurement of specific HIV RNA in blood; the amount of viral RNA per mL of blood (viral load) is a very useful indicator of the progress of infection by HIV and its response to treatment. Both of the above tests indicate that infection with HIV has occurred. The measurement of CD4⁺ lymphocytes in blood is another extremely important lab test. These are special cells of the immune system, whose number gives an indication of the body's ability to fight opportunistic infections. HIV invades these cells, resulting in their death and a decrease in their number. When the CD4⁺ count declines below a certain level (less than 200 per uL), this indicates that the affected individual has a significantly increased likelihood of developing one or more of these infections. The significance of each of these tests should be discussed with a physician.

What Can Be Done To Prevent HIV Infection? To prevent HIV infection, avoid all activities which would put you into contact with possibly infected blood, semen and vaginal secretions. This means that you should use a condom for vaginal, rectal or oral sex. It also means not to share needles if you are injecting intravenous drugs, getting tattoos, or getting your ears pierced. The risk of acquiring HIV through a blood transfusion has been virtually eliminated through screening measures. Less well known than the preventative measures already listed is medical protection for your unborn child, if you are pregnant and suspect you might be infected. Please see a doctor immediately, since there are drugs that exist to decrease your child's risk of acquiring HIV.

How Is HIV Infection Treated? Currently, the mainstay of HIV treatment are medications known as anti-retrovirals which include Retrovir (azidothymidine [AZT]), Invirase (saquinavir) and Viramune (nevirapine). Although each of these drugs targets a different aspect of the virus, they all aim to stop the virus from replicating and thus prolong the time period during which the patient experiences little or no symptoms. It has been proven to be most effective to combine different anti-retrovirals, most commonly three anti-retrovirals. Rarely is a single drug used. It is important to be in close communication with a physician, since a critical aspect of treatment is monitoring the amount of virus a patient has in his/her body, in order to develop the most effective drug therapy. Anti-retrovirals, unfortunately, have numerous side effects which include headache, stomach pain, hepatitis, nerve damage, pancreatitis, kidney stones, skin rashes and anemia, depending on the drug. Please discuss any of your concerns with your physician. The development of HIV therapy is constantly evolving and each year new drugs are being introduced. Check Health Canada's website: http://www.hc-sc.gc.ca for further information. There are also specific treatments for each of the HIV-related conditions mentioned above. These vary from treatment with antibiotics for opportun- istic infections, to palliative care with drugs which help decrease pain. Vaccines for HIV are being developed; however, it will take a number of years before they will be available in the market. Currently there is no known cure for HIV and AIDS, although with the significant amount of interest and work the scientific community has invested in AIDS research, there is hope that one day there will be a cure.