HIV stands for the human immunodeficiency virus, which is the virus that causes AIDS. HIV is different from most other viruses because it attacks the immune system. There are two types of HIV virus – type 1 is found all around the world, while type 2 is found primarily in West Africa. The illness caused by these different virus strains can be different. For example the onset of illness in a person infected by HIV-2 is usually slower and less severe than if the person were infected by HIV-1. Once a person becomes infected by the HIV virus, the infection cannot be cured, but can often be managed by a range of anti-HIV medications, which inhibit the virus’s ability to replicate inside the body. HIV causes illness by damaging the immune system. HIV targets and destroys a special type of immune cell called T cells, which are part of the white blood cell family. These cells are an integral part of the immune system because they lead the fight against infections. When T cells become infected by the HIV virus they become severely damaged and usually die. This damages the person’s ability to fight infections and they often get sick for diseases that do not affect people with healthy immune systems. Over time, a person who is infected with HIV will experience a drop in white blood cell numbers until their immune system becomes completely overwhelmed or exhausted. At this point T cell numbers drop below a certain threshold and the illness is then referred to as AIDS. Having AIDS means that the virus has weakened the immune system to the point at which the body has a very difficult time fighting infections. The time in takes for HIV to progress to AIDS is extremely variable and can range for several years to many decades. The virus is primarily found in the blood, semen and vaginal fluid of an infected person and HIV is referred to as a sexually transmitted disease because the most common way of getting it is through unprotected sexual contact with an infected person. Because HIV is found in the blood, it can also spread between people who share needles or syringes. The virus is also able to cross the placental barrier; therefore women who are HIV positive can transmit the disease to their children. This can occur before or during birth. HIV can also be transmitted through breastfeeding.
The first symptoms of HIV infection are very non-specific and often resemble symptoms associated with the common cold or flu. These types of symptoms can occur within days or weeks after the initial infection, and is referred to as the primary or acute HIV infection phase.During this time many people with HIV do not experience any immediate symptoms, but others may experience headaches, sore throat, fever, fatigue, swollen lymph nodes or rashes.
Once the primary or acute infection phase is over, most people do not experience any visible symptoms for another 8 to 10 years. During this time the immune system gradually becomes weaker until the disease progresses to AIDS, which means that the virus has destroyed many T cells and the immune system has become very weak. People with AIDS have a very difficult time fighting infections and the next phase of symptoms is often associated with opportunistic infections. These types of infections result from disease-producing agents called pathogens, which can easily cause disease because the immune system is so weak. Common infections suffered by individuals with AIDS include pneumonia, fungal infections, tuberculosis and toxoplasmosis.
The only way to diagnose HIV is through a specific test, called an antibody test. Once HIV enters the body, the body starts to produce antibodies (molecules that fight infection) against the virus. Antibody tests detect the specific antibodies produced by the immune system in response to infection with HIV. For the test to be effective, the body’s immune system needs to start producing antibodies against the virus, which takes time. It usually takes between 2 weeks and 6 months from the initial infection and the period in which antibodies become detectable. The usual time period for the body to start producing antibodies against HIV is 3 months, and up until this time standard HIV testing is ineffective. There are many places that offer HIV testing. These include health departments, hospitals and the doctor’s office.
There are approximately 30 different approved drugs available to treat people infected with HIV. These drugs fall into four major classes.
Reverse transcriptase inhibitors (RTIs) are a class of antiretroviral drug used to treat HIV infection. RTIs inhibit the activity of an enzyme called reverse transcriptase, which is required by HIV to reproduce.
Protease inhibitors are a class of medications used to treat infection by viruses, including HIV and Hepatitis C. These drugs interfere with the protease enzyme that HIV uses to produce new viral particles.
Entry inhibitors, also known as fusion inhibitors, are a class of antiretroviral drugs used in combination therapy for the treatment of HIV. These drugs interfere with the binding, fusion and entry of HIV into human cells. By blocking this process entry inhibitors slow the progression of HIV infection to AIDS.
Integrase inhibitors are a class of antiretroviral drug developed for the treatment of HIV infection, although they are not necessarily limited to HIV treatment. They block the action of integrase, an enzyme that integrates genetic material from the virus into its target cell. This limits the damage to T cells caused by HIV.
The drugs currently available do not cure HIV infection or AIDS. Hence, people with HIV need to continuously take antiretroviral drugs. HIV treatment can be very effective if a number of drugs are used synonymously. Multidrug combination products combine drugs from more than one class into a single product and they can suppress the activity virus, even to undetectable levels.
HIV is not transmitted through casual contact. For example the virus can not be transmitted through day-to-day activities such as shaking hands, hugging, or a casual kiss. HIV does not survive outside the body very well. Therefore the environment does not pose a high risk to infection. For example you cannot become infected from a toilet seat, or drinking from a water fountain, or touching a doorknob, dishes, or drinking glasses that an infected person may have touched. HIV is also unable to survive in mosquitoes; therefore they are not a reservoir for the virus.
The most common ways people get HIV are through :-
· Sexual intercourse
· Direct exposure to contaminated blood
· Transplacental transmission from mother to foetus
Adults are most commonly infected by HIV by having sexual intercourse with an infected person. This is because during intercourse, the virus is able to enter the body through the mucosal linings of the vagina, vulva, penis, or rectum. The virus is rarely transmitted to the mouth or upper gastrointestinal tract after oral sex. Your risk of becoming infected by HIV may increase as a result of other factors that damage the mucosal layers lining these areas, such as other sexually transmitted infections that cause ulcers or inflammation. Cells in the mucosal layers carry the virus from the site of infection to the lymph nodes where other immune system cells can become infected.
HIV also can be transmitted by contact with infected blood, most often by the sharing of needles or syringes, which can be contaminated by small quantities of blood containing the virus.
Most HIV-infected children obtain the virus from their mothers before or during birth. The risk of a HIV-infected mother passing the virus to her baby is around 25 percent. This risk is reduced if the mother is taking anti-HIV medication.
There are many factors that may increase the risk of becoming infected with HIV. These include:-
· Injecting drugs or steroids using needles or syringes containing infected blood
· Having unprotected sex with a person that is infected, or with people whom you know little about regarding their sexual history
· Having unprotected sex with anonymous people
· Being infected with other diseases such as hepatitis or tuberculosis
· Already being infected with a sexually transmitted disease such as syphilis
· Having unprotected sex with a person that may be at risk of any of these factors
There are many ways to prevent being infected by HIV, or reducing the risk of passing the virus on to someone else. These include:-
· Only have sex with a person whose sexual history you are aware of
· If you or your partner has HIV use a latex condom to prevent the other becoming infected
· If you have a number of sexual partners, protect yourself from HIV by:-
o Talking about HIV with each partner before you have sex. Ask your partners if they have recently been tested for HIV
o Learning as much as you can about each partner’s past behaviour (sex and drug use), and consider the risks to your health
o Always have protected sex
o Getting tested for HIV
· Do not inject illicit drugs. If you do inject illicit drugs, protect yourself from HIV by:-
o Never sharing needles or syringes
o Using only clean needles or syringes
o Not exposing yourself to someone else’s blood