HIV stands for Human Immunodeficiency Virus. HIV is a virus. Some viruses, such as the ones that cause the common cold or the flu, stay in the body only for a few days. Some viruses, such as HIV, never go away. When a person becomes infected with HIV, that person becomes "HIV positive" and will always be HIV positive. Over time, HIV disease infects and kills white blood cells called CD4 lymphocytes (or "T cells") and can leave the body unable to fight off certain kinds of infections and cancers.

With successful antiretroviral therapy (ART), the body can remain healthy and fight off most viruses and bacteria. A healthy person usually has a CD4 count of between 600 and 1,200. When the CD4 count drops below 200, a person's immune system is severely weakened, and that person is then diagnosed with AIDS, even if he or she has not become sick from other infections.

AIDS stands for Acquired Immunodeficiency Syndrome and is caused by HIV. The names HIV and AIDS can be confusing because both terms describe the same disease. Think of AIDS as advanced HIV disease. A person with AIDS has an immune system so weakened by HIV that the person usually becomes sick from one of several opportunistic infections or cancers such as PCP (a type of pneumonia) or Kaposi sarcoma, wasting syndrome (involuntary weight loss), memory impairment, or tuberculosis. If someone with HIV is diagnosed with one of these opportunistic infections (even if the CD4 count is above 200), he or she is said to have AIDS. AIDS usually takes time to develop from the time a person acquires HIV -- usually between 2 to 10 years or more.

Once a person has been diagnosed with AIDS, she or he is always considered to have AIDS, even if that person's CD4 count goes up again and/or they recover from the disease that defined their AIDS diagnosis.

How does HIV cause illnesses?

HIV reproduces continuously in the body from the first day of infection. A person who is infected with HIV will typically produce about 10 billion new HIV particles each day, and about 2 billion virus-fighting immune system cells (CD4 T cells- are produced and destroyed).

A person's immune system attacks HIV soon after infection, and at first is able to clear a large amount of virus from the body every 24 hours. However, for each virus particle cleared, at least one new one is created. The body's initial, vigorous anti-HIV response creates a temporary equilibrium between immune cells and the virus that may last for months or years.

Typically, a person will show no outward signs of illness during this time, except for severe flu-like symptoms after the initial infection as a sign that the immune system is kicking-in to fight off HIV.

Over time, however, the virus gains the upper hand. The amount of HIV in the body (viral load) increases and the CD4 T cell count declines.

The immune system cannot work properly under constant attack from HIV. Eventually, the virus overwhelms the defenses of the immune system, which then can no longer ward off other illness-causing infections, some of which can be life threatening.

HIV Transmission

HIV Must Be Present-Infection may only occur if one of the persons involved in an exposure situation is infected with HIV. Some people assume that certain behaviors or exposure situations can cause HIV disease, even if the virus is not present. This is not true.

There Needs to Be Enough Virus-The concentration of HIV determines whether infection will occur. In blood, for example, the virus is very concentrated. A small amount of blood is enough to infect someone. Also, the concentration of virus in blood or other fluids can change, in the same person, over time.

HIV Must Get into the Bloodstream-It is not enough to be in contact with an infected fluid for HIV to be transmitted. Healthy, intact skin does not allow HIV to get into the body.

HIV can enter through an open cut or sore, or through contact with the mucous membranes. Transmission risk is very high when HIV comes in contact with the more porous mucous membranes in the genitals, the anus, and the rectum, which are inefficient barriers to HIV. Transmission is also possible through oral sex because body fluids can enter the bloodstream through cuts in the mouth.

Paths of Infection-HIV can be transmitted through:

• Unprotected vaginal, anal and oral sex
  
• Direct blood contact, which may occur through needle sharing, transfusions, accidents in health care settings, or certain blood products
  
• Mother to baby; before or during birth or through breast milk

Infectious Fluids-HIV can be transmitted from an infected person to another through:

• Blood Semen (including pre-seminal fluid)
  
• Vaginal secretions HIV can also be transmitted through the following bodily secretions, in limited circumstances where there is exposure to large quantities
  
• Breast milk-expressed through feeding

Non-Infectious Fluids

• Saliva-is NOT considered to be infectious. The only time saliva would pose a risk would be if it had blood present in it. There are no documented cases of HIV transmission through saliva. There is a protein in the mouth that attaches itself to the surface of blood cells and blocks infection by HIV that appears to be present in the mucous membrane in the mouth at a level sufficient enough to reduce the concentration of HIV in saliva to non-infectious levels.
  
• Urine and Tears - are NOT considered infectious. While HIV has been found in urine and tears, it is not concentrated in an amount sufficient for transmission.
  
• Sweat, Feces, Vomit - are NOT considered infectious. HIV has never been found in these materials. The only possible risk would be if there was blood present.

HIV can enter the body through open cuts or sores and by directly infecting cells in the mucous membranes.

Transmission can happen in the mouth, the eyes, vagina, penis (through the urethra), in the anus and rectum. HIV cannot cross healthy, unbroken skin.

Sexual Transmission
HIV can be transmitted through sexual intercourse, both vaginal and anal. HIV can easily pass through the mucus membranes in the genitals and the rectum, or may pass through cuts and sores.

HIV can also be transmitted through oral sex. Conditions such as bleeding gums and poor oral health increase the risk of transmission and through oral sex.

Non-sexual Transmission
HIV can be transmitted by contact between infectious fluids and bleeding cuts or open sores in the skin. However, healthy, intact skin does not allow HIV to enter the body, and provides an excellent barrier against the virus.

Sharing Needles-Sharing syringes [needles, works or fits] to inject medicines, hormones, steroids or illegal drugs can pass blood directly from one person's blood stream to another's. It is also a very efficient way to transmit HIV and other blood borne viruses such as Hepatitis B (HBV) and Hepatitis C (HCV).

Tattoos and Piercing-There have been NO documented cases of transmission of HIV by piercing or tattooing. However, there are documented cases of Hepatitis B (HBV) through these routes. Since Hepatitis B and HIV are transmitted by the same activities, there may be a possibility of HIV transmission through tattoos and piercing.

Blood Transfusions-Since March 1985, all blood in the United States has been screened for HIV using the HIV antibody test. This practice has almost eliminated the risk of getting HIV through a blood transfusion in the United States.

Hemophiliacs-Since March 1985, all blood in the United States has been screened for HIV with the HIV antibody test. This practice has almost eliminated the risk of getting HIV through a blood transfusion in the United States. Other Blood Products. Besides whole blood, platelets [red blood cells] have transmitted HIV.

Current blood screening should prevention infection from these products. No other blood products are suspected of transmitting HIV.

Donor Insemination-This is not a regulated industry. It is recommended that donor semen be checked for the presence of HIV. When collecting semen, donors should be tested for HIV antibodies when the sample is taken. The semen should then be frozen. The donor should then be retested three months later to avoid the risk of a "window period" effect. The semen should not be used before the procedure is completed.

Organ Donation-People who are infected with HIV are encouraged not to donate organs or tissue for transplant purposes. There were very few cases of organ or tissue transplant HIV transmission from 1985 until 1994 when new government guidelines were implemented to reduce the risk of transplant transmission. These guidelines require blood from donors be tested for various strains of HIV.

Also, the donor medical history must show no evidence of risk factors or clinical symptoms of HIV infection.

Mother to Infant Transmission-It is possible for a mother who has HIV to pass the virus to her fetus, by exposure to blood and vaginal fluids during birth, or through breast milk during feeding.

Most people newly infected with the HIV virus show few, if any, symptoms for a few years. But during this asymptomatic period, HIV is actively multiplying, infecting, and killing cells in the immune system, particularly CD4+ T cells. People are very infectious during this early phase.

As the immune system weakens, symptoms begin to emerge.

Early Symptoms Of HIV Infection

Some people, but not all, develop symptoms within a month or two of exposure to HIV. These people may have a flu-like illness with such symptoms as:

• Fever
• Rash
• Headache
• Loss of appetite
• Swollen glands (enlarged lymph nodes)
• Achy muscles and joints

These early symptoms usually disappear within a week to a month. Most HIV-infected people who experience these early symptoms won't see any more signs of the infection for at least a few years.

Later Symptoms Of HIV Infection

Usually, it takes about eight to nine years between the time of infection and the appearance of later symptoms, although this varies from person to person. These symptoms signal that immune system function is deteriorating, due to declining numbers of CD4+ T cells.

Not all people with HIV infection develop further symptoms. For those who do, however, symptoms may include:

• Persistent, enlarged lymph nodes
• Excessive fatigue
• Weight loss
• Frequent fevers
• Night sweats
• Chronic or frequent diarrhea
• Genital sores (sores around the penis or vagina)
• Thrush (an infection of the mouth caused by Candida, a yeast-like fungus) and mouth lesions
• Skin rash or flaky skin
• Joint stiffness and pain
• Bone pain
• Blurred vision
• Short-term memory loss
• Repeated bacterial, viral, or fungal infections

As the CD4+ T cell count continues to drop and the immune system deteriorates further, individuals may continue to experience the above symptoms as well as develop new ones.

What Symptoms Signal The Onset Of AIDS?

An HIV-infected person receives an AIDS diagnosis when he or she has:

• A CD4+ T cell count of less than 200, and/or
• At least one of more than two dozen opportunistic infections and conditions

In the United States, the most common AIDS-defining condition in both women and men is a lung infection called Pneumocystis carinii pneumonia , abbreviated PCP.

Other AIDS-defining conditions include severe body wasting and Candida infection of the esophagus, windpipe, or lungs.

A blood test is used to confirm whether a person has been infected with HIV. Anyone who has engaged in risky behavior - such as sharing drug - injecting equipment or having unprotected sexual contact with an infected person or with someone whose HIV status is unknown - should consider being tested.

A positive HIV test result does not mean that a person has AIDS. Not everyone who has HIV infection develops AIDS. Experts estimate that about half the people with HIV will develop AIDS within 10 years after becoming infected.

Early diagnosis of HIV infection is important because:

• It allows people to seek treatment that will help suppress HIV's attack on the immune system and prevent opportunistic infections.

• It helps women at risk for HIV infection who are planning a pregnancy or who are already pregnant take steps to reduce the risk of transmitting the infection to the baby.
  
• It alerts those who are infected that they could infect others.

What Kinds Of Blood Tests Are Used?

The blood tests most commonly used to diagnose HIV infection work by measuring the levels of antibodies produced by the body against HIV. Antibody-detecting assays, or tests, include the:

• Enzyme immunoassay (EIA)

• Enzyme-linked immunosorbent assay (ELISA)

• Western blot test

Usually, the first test that laboratories use to detect the presence of HIV antibodies is an EIA or the ELISA. If the first test produces a positive result (HIV antibodies appear to be present), then the more sensitive Western Blot test is used to confirm it.

EIA or ELISA tests take from one to two weeks to complete, depending on where the test is performed.

Why Is It Often Necessary To Repeat An HIV Test?

Although a negative result on an HIV blood test usually means that the person is not infected with the virus, that is not always the case. The body may take three to six months after exposure to the virus to produce enough antibodies to be detectable in the bloodstream.

Because of this delay between infection and the appearance of HIV antibodies, a person should be retested six months after the last possible exposure to HIV. It is also important to remember that a person who has been exposed to HIV can pass the virus to others even before HIV antibodies appear in the bloodstream.

HIV Treatment

In the time between initial infection and AIDS, the infected person may feel relatively normal, despite the constant attack by HIV. People living with HIV have to understand, however, that despite feeling well on the outside, significant damage can be occurring on the inside. Fortunately, over the past five years, significant progress has been made regarding the treatment of HIV and prevention of some of the infections and cancers that may be caused by it. Antiretroviral medications can directly attack HIV and stop it from reproducing and causing further damage. For most people, the biggest factor in preventing progression to AIDS is adherence to HAART, which can suppress HIV replication to very low levels and not allow it to continue to attack the body.

Although there is no treatment currently available that can cure people of HIV or AIDS, a number of therapies have been developed to help them stay healthier and live longer.

• Some medications target HIV itself, to reduce the virus's assault on the immune system, or to even prevent the virus from entering human immune cells.

• Other treatments are used to treat or prevent specific opportunistic infections that threaten the health of people with HIV-damaged immune systems.

Treatments That Suppress HIV

Drugs that interfere with the activity of a retrovirus such as HIV are generally known as antiretrovirals. Nearly all antiretroviral medications currently approved to treat HIV infection target two viral enzymes used by the virus to replicate itself. These enzymes, reverse transcriptase and protease, are involved in different stages of viral replication. A new treatment approved in the past year works in a completely new way by preventing the virus from entering the human immune cells.

Four classes of antiretroviral drugs have been developed to interfere with the activity of these viral enzymes and slow down the multiplication of the virus. These are:

• Nucleoside analog reverse transcriptase inhibitors (NRTIs). NRTIs interrupt an early stage of HIV replication by interfering with the activity of reverse transcriptase.
• AZT (zidovudine), the first drug approved for treating HIV infection, is an NRTI, as are zalcitabine (ddC), didanosine (ddI), stavudine (d4T), lamivudine (3TC), and abacavir.
• Non-nucleoside reverse transcriptase inhibitors (NNRTIs). NNRTIs also work by hindering the action of reverse transcriptase. This class of drugs includes delavirdine, nevirapine, and efavirenz.
• Protease inhibitors. Protease inhibitors interrupt a later stage of viral replication. This class of drugs includes saquinavir, indinavir, ritonavir, nelfinavir, and amprenavir.
• Fusion inhibitors. Fusion inhibitors prevent HIV from entering human immune cells. The only fusion inhibitor approved to date is enfuvirtide.

Studies have found that various combinations of antiretroviral drugs are more effective in suppressing HIV than antiretroviral drugs used alone. Experts refer to one common treatment approach, usually involving a protease inhibitor combined with two other antiretroviral drugs, as "highly active antiretroviral therapy" or HAART.

Drug combinations, or drug "cocktails," also can help reduce the risk that drug-resistant HIV will develop. When drug resistance occurs, medications that initially succeeded in suppressing the replication of HIV in the patient's body loose their effectiveness. Enfuvirtide works in a unique way that reduces the likelihood of cross-resistance with other HIV drugs.

Antiretroviral drugs have side effects that can limit their use in some people.

AZT, for example, may result in a loss of blood cells.

Protease inhibitors can cause nausea, diarrhea, and other symptoms.

Treating AIDS-Related Conditions

Other drugs and therapies are used to prevent or treat opportunistic infections and other AIDS-related conditions:

Pneumocystis carinii pneumonia. People who develop this lung infection are generally treated with TMP/SMX (a combination of antibiotic drugs) or pentamidine. Doctors also prescribe these medications as preventive therapy for adult patients whose CD4+ T cell counts fall below 200.

Yeast infections in women. Physicians often prescribe a drug called fluconazole to treat yeast and other fungal infections. Fluconazole also can safely prevent vaginal and esophageal candidiasis without development of drug resistance.

Severe skin ulcers caused by herpes simplex virus infection. Skin ulcers sometimes respond to an antiviral medication, acyclovir.

Pelvic inflammatory disease. PID is treated with antibiotics. Women with mild cases may be treated on an outpatient basis. HIV-positive pregnant women suspected of having PID are usually hospitalized, treated with intravenous antibiotics approved for use during pregnancy, and monitored closely.

HIV-related wasting. Megestrol acetate (Megace) is often prescribed for HIV-associated wasting, but it can cause significant irregular vaginal bleeding in women. Another drug, nandrolone, may not have these side effects and is currently undergoing drug trials.

Kaposi's sarcoma and other cancers. Cancers are treated with radiation, chemotherapy, or injections of alpha interferon, a genetically engineered, naturally occurring protein.

CMV Retinitis. Improvements in anti-HIV treatments as well as preventive and therapeutic approaches to managing CMV have resulted in a decreased incidence of CMV retinitis. Today, the incidence of CMV retinitis is about one quarter what it was previous to the introduction of HAART. While early CMV retinitis therapies were delivered intravenously, current treatments include medications in pill form for all stages of CMV retinitis.

What Are Some Of The Problems With AIDS Drug Therapy?

AIDS drugs do not cure the condition, but they help to manage it and postpone life-threatening complications. However, there are problems with AIDS drug therapy:

Side effects of drugs are a major concern in treatment.

Another major problem is the cost of the drugs used in treating AIDS. AIDS patients in the United States depend on insurance and government grants to obtain them. The high price of these drugs makes it difficult for third-world countries, which have major AIDS epidemics, to afford to distribute them.

Since antiviral drugs have so far not been curative, the hope is to find a vaccine. The technology for vaccine development is present, and serious efforts are being made to find one.

How Can The Psychological Impact Of AIDS Be Managed?

When people learn they have tested positive for the HIV virus, they may experience a number of stressful psychological reactions. Depression and anxiety leading to panic attacks may require the help of an adviser or psychological therapist. Counseling services are available in most HIV clinics. Group therapy sessions with other HIV-positive people may also be helpful in managing feelings of stress and guilt.

People with AIDS who show signs and symptoms of organic central nervous system involvement, such as confusion and memory loss, need particular support. In their cases there is a need for additional medical and psychiatric intervention.

Antidepressant drugs should be used under the advice of a specialist in case of a severe depressive episode. HIV-infected people may take antidepressant drugs, but they are usually more sensitive to their side effects.

Conclusion

HIV disease is a chronic disease that used to be fatal for virtually everyone who got it. Now, things have changed and effective treatments are available to treat HIV and, in most cases, these treatments can prevent HIV from doing further damage and can keep the person healthy. In order to take advantage of these treatments, you must be tested and diagnosed with HIV. All persons who may have been infected with HIV and virtually all pregnant women should be tested as soon as possible.