HIV AND AIDS INFECTION

HIV/AIDS Overview
HIV (human immunodeficiency virus) infection has now spread to every country in the world. Approximately 40 million people are currently living with HIV infection, and an estimated 25 million have died from this disease. The scourge of HIV has been particularly devastating in sub-Saharan Africa, but infection rates in other countries remain high. In the United States, approximately 1 million people are currently infected. Here are a few key points about the disease:
• Globally, 85% of HIV transmission is heterosexual.

• In the United States, approximately one-third of new diagnoses appear to be related to heterosexual transmission. Male-to-male sexual contact still accounts for approximately half of new diagnoses in the U.S. Intravenous drug use contributes to the remaining cases. Because the diagnosis may occur years after infection, it is likely that a higher proportion of recent infections are due to heterosexual transmission.

• Infections in women are increasing. Worldwide, 42% of people with HIV are women. In the United States, approximately 25% of new diagnoses are in women, and the proportion is rising.

• There is good news on one front. New HIV infections in U.S. children have fallen dramatically. This is largely a result of testing and treating infected mothers, as well as establishing uniform testing guidelines for blood products.
In order to understand HIV and AIDS, it is important to understand the meanings behind these terms:
• HIV stands for the human immunodeficiency virus. It is one of a group of viruses known as retroviruses. After getting into the body, the virus kills or damages cells of the body's immune system. The body tries to keep up by making new cells or trying to contain the virus, but eventually the HIV wins out and progressively destroys the body's ability to fight infections and certain cancers.

• AIDS stands for the acquired immunodeficiency syndrome. It is caused by HIV and occurs when the virus has destroyed so much of the body's defenses that immune-cell counts fall to critical levels or certain life-threatening infections or cancers develop.
HIV/AIDS Transmission
HIV is transmitted when the virus enters the body, usually by injecting infected cells or semen. There are several possible ways in which the virus can enter.
• Most commonly, HIV infection is spread by having sex with an infected partner. The virus can enter the body through the lining of the vagina, vulva, penis, rectum, or mouth during sex.

• HIV frequently spreads among injection-drug users who share needles or syringes that are contaminated with blood from an infected person.

• Women can transmit HIV to their babies during pregnancy or birth, when infected maternal cells enter the baby's circulation.

• HIV can be spread in health-care settings through accidental needle sticks or contact with contaminated fluids.

• Very rarely, HIV spreads through transfusion of contaminated blood or blood components. Blood products are now tested to minimize this risk. If tissues or organs from an infected person are transplanted, the recipient may acquire HIV. Donors are now tested for HIV to minimize this risk.

• People who already have a sexually transmitted disease, such as syphilis,genital herpes, chlamydial infection, gonorrhea, or bacterial vaginosis, are more likely to acquire HIV infection during sex with an infected partner.
The virus does not spread through casual contact such as preparing food, sharing towels and bedding, or via swimming pools, telephones, or toilet seats. The virus is also unlikely to be spread by contact with saliva, unless it is contaminated with blood.

HIV/AIDS Symptoms and Signs
Many people with HIV do not know they are infected.
• Many people do not develop symptoms after they first get infected with HIV. Others have a flu-like illness within several days to weeks after exposure to the virus. They complain of fever, headache, tiredness, and enlarged lymph nodes in the neck. These symptoms usually disappear on their own within a few weeks. After that, the person feels normal and has no symptoms. This asymptomatic phase often lasts for years.

• The progression of disease varies widely among individuals. This state may last from a few months to more than 10 years.

o During this period, the virus continues to multiply actively and infects and kills the cells of the immune system.

o The virus destroys the cells that are the primary infection fighters, a type of white blood cell called CD4 cells.

o Even though the person has no symptoms, he or she is contagious and can pass HIV to others through the routes listed above.
AIDS is the later stage of HIV infection, when the body begins losing its ability to fight infections. Once the CD4 cell count falls low enough, an infected person is said to have AIDS. Sometimes, the diagnosis of AIDS is made because the person has unusual infections or cancers that show how weak the immune system is.
• The infections that happen with AIDS are called opportunistic infectionsbecause they take advantage of the opportunity to infect a weakened host. The infections include (but are not limited to)

o pneumonia caused by Pneumocystis, which causes wheezing;

o brain infection with toxoplasmosis which can cause trouble thinking or symptoms that mimic a stroke;

o widespread infection with a bacteria called MAC (mycobacterium avium complex) which can cause fever and weight loss;

o yeast infection of the swallowing tube (esophagus) which causes pain with swallowing;

o widespread diseases with certain fungi like histoplasmosis, which can cause fever, cough, anemia, and other problems.

• A weakened immune system can also lead to other unusual conditions:

o lymphoma in (a form of cancer of the lymphoid tissue) the brain, which can cause fever and trouble thinking;

o a cancer of the soft tissues called Kaposi's sarcoma, which causes brown, reddish, or purple spots that develop on the skin or in the mouth.

When to Seek Medical Care
If you have engaged in unprotected sex outside of a mutually monogamous relationship or shared needles while using drugs, you should have an HIV test. Early detection and treatment of the infection can slow the growth of HIV.
• If you are pregnant and infected with HIV, you may be able to reduce the risk to your unborn child by getting treatment early.

• You can also avoid infecting others if you know that you have the disease. Testing is available anonymously and confidentially. You can even test yourself at home.
People known to have HIV infection or AIDS should go to the hospital any time they develop high fever, shortness of breath, coughing up blood, severe diarrhea, severe chest orabdominal pain, generalized weakness, severe headache, seizures, confusion, or a change in mental status. These may be the indication of a life-threatening condition for which an urgent evaluation in the hospital's emergency department is recommended. All infected people should be under the regular care of a physician skilled in the treatment of HIV and AIDS.

HIV/AIDS Diagnosis
HIV infection is commonly diagnosed by blood tests. There are three main types of tests that are commonly used: (1) antibody tests, (2) RNA tests, and (3) a combination test that detects both antibodies and a piece of the virus called the p24 protein. In addition, a blood test known as a Western blot is used to confirm the diagnosis.
No test is perfect. Tests may be falsely positive or falsely negative. For example, it can take some time for the immune system to produce enough antibodies for the antibody test to turn positive. This time period is commonly referred to as the "window period" and may last six weeks to three months following infection. Therefore, if the initial antibody test is negative, a repeat test should be performed three months later. Early testing is crucial, because early treatment for HIV helps people avoid or minimize complications. Furthermore, high-risk behaviors can be avoided, thus preventing the spread of the virus to others.
Testing for HIV is usually a two-step process. First, an inexpensive screening test is done. If that test is positive, a second test (Western blot) is done to confirm the result. Antibody tests are the most common initial screening test used. There are different types of antibody screening tests available:
• Most commonly, blood is drawn for an enzyme immunoassay (EIA). The test is usually run in a local laboratory, so results can take one to three days to come back.

• Other tests can detect antibodies in body fluids other than blood such as saliva, urine, and vaginal secretions. Some of these are designed to be rapid tests that produce results in approximately 20 minutes. These tests have accuracy rates similar to traditional blood tests.

• HIV home-testing kits are available at many local drug stores. Blood is obtained by a finger prick and blotted on a filter strip. Other test kits use saliva or urine. The filter strip is mailed in a protective envelope to a laboratory to be tested. Results are returned by mail in one to two weeks.

• All positive antibody screening tests must be confirmed with a follow-up blood test called the Western blot to make a positive diagnosis. If the antibody test and the Western blot are both positive, the likelihood of a person being HIV infected is >99%. Sometimes, the Western blot is "indeterminate," meaning that it is neither positive nor negative. In these cases, the tests are usually repeated at a later date. In addition, an RNA test for the virus might be done.
Other tests, such as those that look for virus RNA and the combination test, are not commonly used for screening.

HIV/AIDS Treatment
Medications
Over the past years, several drugs have become available to fight both the HIV infection and its associated infections and cancers. These drugs are called highly active antiretroviral therapy (HAART) and have substantially reduced HIV-related complications and deaths. However, there is no cure for HIV/AIDS. Therapy is initiated and individualized under the supervision of a physician who is an expert in the care of HIV-infected patients. A combination of at least three drugs is recommended to suppress the virus from replicating and boost the immune system. The following are the different classes of medications used in treatment.
• Reverse transcriptase inhibitors: These drugs inhibit the ability of the virus to make copies of itself. The following are examples:

o Nucleoside or nucleotide reverse transcriptase inhibitors (NRTIs). These include medications such aszidovudine (AZT/Retrovir), didanosine (ddI/Videx), zalcitabine (ddC/Hivid),stavudine (d4T/Zerit), lamivudine (3TC/Epivir), abacavir (ABC/Ziagen),emtricitabine (FTC/Emtriva), and tenofovir (Viread).

o Non-nucleoside reverse transcriptase inhibitors (NNRTIS) are commonly used in combination with NRTIs to help keep the virus from multiplying. Examples of NNRTIs are efavirenz (Sustiva), nevirapine (Viramune), anddelavirdine (Rescriptor). Etravirine (Intelence), a newer member of this class of drugs, was approved by the U.S. FDA in 2008.

• Protease inhibitors (PIs): These medications interrupt virus replication at a later step in its life cycle, preventing cells from producing new viruses. These include ritonavir (Norvir), a lopinavir and ritonavir combination (Kaletra),saquinavir (Invirase), indinavir sulphate (Crixivan), amprenavir (Agenerase),fosamprenavir (Lexiva), darunavir (Prezista), atazanavir (Reyataz), tipranavir(Aptivus), and nelfinavir (Viracept). Using PIs with NRTIs reduces the chances that the virus will become resistant to medications.

• Fusion and entry inhibitors are newer agents that keep HIV from entering human cells. Enfuvirtide (Fuzeon/T20) was the first drug in this group. It is given in injectable form like insulin. Another drug called maraviroc (Selzentry) binds to a protein on the surface of the human cell and can be given by mouth. Both drugs are used in combination with other anti-HIV drugs.

• Integrase inhibitors stop HIV genes from becoming incorporated into the human cell's DNA. This is a newer class of drugs recently approved to help treat those who have developed resistance to the other medications.Raltegravir (Isentress) was the first drug in this class approved by the FDA in 2007.
Antiretroviral viral drugs stop viral replication and delay the development of AIDS. However, they also have side effects that can be severe. They include decreased levels of red or white blood cells, inflammation of the pancreas, liver toxicity, rash, gastrointestinal problems, elevated cholesterol level, diabetes, abnormal body-fat distribution, and painful nerve damage.
• Pregnant women who are HIV-positive should seek care immediately because HAART therapy reduces the risk of transmitting the virus to the fetus. There are certain drugs, however, that are harmful to the baby. Therefore, seeing a physician to discuss anti-HIV medications is crucial.

Follow-up
People with HIV infection should be under the care of a physician who is experienced in treating the infection. All people with HIV should be counseled about avoiding the spread of the disease. Infected individuals are also educated about the disease process, and attempts are made to improve the quality of their life.

HIV Prevention
Despite significant efforts, there is no effective vaccine against HIV. The only way to prevent infection by the virus is to avoid behaviors that put you at risk, such as sharing needles or having unprotected sex. In this context, unprotected sex means sex without a barrier such as a condom. Because condoms break, even they are not perfect protection. Many people infected with HIV don't have any symptoms. There is no way to know with certainty whether a sexual partner is infected. Here are some prevention strategies:
• Abstain from sex. This obviously has limited appeal, but it absolutely protects against HIV transmission by this route.

• Have sex with a single partner who is uninfected. Mutual monogamy between uninfected partners eliminates the risk of sexual transmission of HIV.

• Use a condom in other situations. Condoms offer some protection if used properly and consistently. Occasionally, they may break or leak. Only condoms made of latex should be used. Only water-based lubricants should be used with latex condoms.

• Do not share needles or inject illicit drugs.

• If you work in a health-care field, follow recommended guidelines for protecting yourself against needle sticks and exposure to contaminated fluids.

• If you have engaged in risky behaviors, get tested to see if you have HIV.

• The risk of HIV transmission from a pregnant woman to her baby is significantly reduced if the mother takes medications during pregnancy, labor, and delivery and her baby takes medications for the first six weeks of life. Even shorter courses of treatment are effective, though not as optimal. The key is to get tested for HIV as early as possible in pregnancy. In consultation with their physician, many women opt to avoid breastfeeding to minimize the risk of transmission after the baby is born

HIV/AIDS Prognosis
There is no cure for HIV infection. Before we had any treatment for the virus, people with AIDS lived only for a couple of years. Fortunately, medications have substantially improved the outlook and survival rates. Prevention efforts have sharply reduced HIV infection in young children and have the potential to sharply limit new infections in other populations.
• Medications have extended the average life expectancy, and many people with HIV can expect to live for decades with proper treatment. An increasing number have a normal life expectancy if they adhere carefully to medication regimens.

• Medications help the immune system recover and fight infections and prevent cancers from occurring. Eventually, the virus may become resistant to the available drugs, and the manifestations of AIDS may develop.

• Drugs used to treat HIV and AIDS do not eliminate the infection. It is important for the person to remember that he or she is still contagious even when receiving effective treatment.

• Intensive research efforts are being focused on developing new and better treatments. Although currently there is no promising vaccine, work continues on this front.