CAUSE OF AIDS - HIV

The cause of AIDS is a virus known as the human immunodeficiency virus or HIV. The evidence that HIV causes AIDS is overwhelming. First, evidence of HIV infection is easily found in patients with AIDS when such evidence is sought.

Second, the virus has been isolated and grown in pure culture from persons with the disease.

Finally, studies of AIDS cases resulting from blood transfusions have documented the transmission of HIV to previously uninfected persons who have subsequently developed the disease.

HIV TRANSMISSION

Three important facts about HIV transmission are:

• The virus is mainly spread by unprotected sex and sharing needles with an HIV-infected person.
• Babies born to HIV-infected women may become infected.
• You do not become infected by casual contact or through insect bites or stings.

AIDS is caused by a virus called human immunodeficiency virus or HIV. HIV is found in the blood, semen, and vaginal secretions of an infected person. The virus is spread by unprotected sexual intercourse with an infected person, by needle-sharing among injecting drug users, or, less commonly and now very rarely, through transfusions of infected blood or blood clotting factor. Babies born to HIV-infected women may become infected before or during birth, or shortly after birth through breast-feeding.

HIV has been transmitted in very few cases in the household setting. These transmissions are believed to have resulted when infected blood or other body fluids came in contact with skin or mucous membranes. Common sense precautions should be taken in all settings -- including the home -- to prevent contact with the blood and other body fluids of persons who are HIV infected, at risk for HIV infection, or whose infection and risk status are unknown. For example, hands and other parts of the body should be washed whenever contact with blood and other body fluids occurs, and surfaces soiled with blood should be cleaned and disinfected appropriately. People should avoid sharing razors and toothbrushes, which are practices that increase the likelihood of blood contact. Needles and other sharp instruments should be used only when necessary for medical procedures and disposed of according to recommendations for health care settings.

There is no known risk of HIV transmission to coworkers, clients, or consumers from contact in industries such as food service establishments. Food service workers known to be infected with HIV need not be restricted from work unless they have other infections or illnesses (such as diarrhea or hepatitis A). The Public Health Service recommends that all food service workers follow recommended standards and practices of good personal hygiene and food sanitation, which should be available from your local or state health department.

In 1985, CDC issued routine precautions that all personal service workers, such as hairdressers, barbers, cosmetologists, and massage therapists should follow, even though there is no evidence of HIV transmission from a personal service worker to a client or vice versa. Instruments that are intended to go through or penetrate the skin, such as tattooing and acupuncture needles or ear piercing devices, should be used once and thrown away or thoroughly cleaned and then sterilized.

Instruments such as razors, which are not intended to penetrate the skin but which may become contaminated with blood should be used for only one client and thrown away or thoroughly cleaned and disinfected after each use.

Casual contact through closed-mouth or "social" kissing is not a risk for transmission of HIV. However, CDC recommends against "French" or open-mouthed kissing with an infected person because of the possibility of contact with blood.

An investigation by a state health department found a possible case of blood-to-blood transmission of HIV by a human bite. There have been other reports in the medical literature in which HIV appeared to have been transmitted by a bite. Severe trauma with extensive tissue tearing and damage and presence of blood were reported in each of these instances. Biting is not a common way of transmitting HIV. In fact, there are many reports of bites that did NOT result in HIV infection.

The possibilities of transmission of blood borne diseases, such as HIV, through vaccines and various blood products is a concern for some persons. Vaccines such as the hepatitis B vaccine and various immune globulins approved for use in the United States have not been implicated in the transmission of HIV. Hepatitis B vaccine is now genetically engineered and contains no human tissue, blood, or blood product.

Other products that are made from screened plasma and blood donations undergo purification processes which destroy any viruses or bacteria.

Some people have asked why HIV is not transmitted by insects. Studies about the potential for insect transmission of HIV have been carried out by CDC and other scientists the world over.

These studies have shown no evidence of HIV transmission--even in areas where there are many cases of AIDS. These studies have also shown no biological evidence to indicate that HIV is able to infect insect cells or to reproduce in insects. Even if the virus enters the insect via blood it ingests, the insect does not become infected and its saliva does not contain the virus. In contrast, other mosquito-borne viruses, such as dengue or yellow fever, do multiply in the mosquito.

Since the virus cannot reproduce in the insect, theoretical transmission of HIV via mosquitoes would require the ingestion of a large quantity of blood with large amounts of the virus, and the transfer of this blood to the next person it bites.

This has NOT been observed to occur because:

The amount of virus in the circulating blood of HIV-infected persons is very low compared with the levels observed with other viruses known to be transmitted by insects.

Mosquitoes do not regurgitate blood into the next person they bite. The blood someone sees when they slap a mosquito on their skin is usually their own.

The saliva of mosquitoes does not contain the virus.

It should also be reassuring to know that insect transmission of hepatitis B virus or HBV, another blood borne virus, has never been reported. This lack of insect transmission is evident even though the amounts of HBV in blood are many times greater than the amounts of HIV in blood.

In addition, community or village-wide studies were conducted in Africa and Florida and included people who often worked and lived together in unsanitary and crowded conditions. In these studies, no secondary or household transmission was observed despite countless opportunities for shared mosquito and bed bug bites.

SURVIVAL OF HIV IN THE ENVIRONMENT

Concerning the survival of HIV in the environment, two facts are:

HIV does not survive well outside the body.

HIV has to be grown in large amounts to be studied in laboratories.

Although HIV has been kept alive under certain laboratory conditions, medical authorities agree that the virus does not survive well in the environment. To put things into perspective, 1 milliliter (ml) of blood from a hepatitis B-infected person may contain more than 100 million infectious viral particles. In a dried state, hepatitis B virus, or HBV, may remain viable on surfaces for up to 1 week, and possibly longer. In contrast to the very high concentrations of HBV, the concentrations of HIV in the blood of infected persons are much lower. Estimates of the number of infectious viral particles range from a few hundred to approximately 10,000 per ml. CDC laboratory studies have shown that drying HIV reduces the viral amounts by 90 to 99 percent within several hours. The concentrations of HIV used in some laboratory studies have produced results that have been used to alarm people unnecessarily.

The results are not meaningful because:

the concentrations of HIV used were many times greater than that found in patient specimens;

the amounts of virus studied are not found in nature;

no one has been infected with HIV due to contact with an environmental surface.

Neither HBV nor HIV are able to reproduce outside the human body, unlike bacteria or fungi which do so under suitable conditions. In laboratory studies of HIV and HBV, it was biologically necessary for these viruses to infect specific human or primate cells to complete their life cycles and thereby reproduce themselves.

PREVENTION OF HIV INFECTION

To prevent HIV infection:

Always practice safer sex-(wear a condom).

Do NOT share needles with an infected person.

To prevent the spread of HIV infection, avoid behavior that might result in contact with blood, semen, vaginal secretions, or body fluids with visible blood. Specifically, practice safer sex with your partner, and do NOT share "injecting drug works."

 The following prevention measures apply to personal sex practices and injecting drug use:

To prevent sexual transmission of HIV, abstain from sex with an infected person.

Ask about the sexual history of current and future sex partners.

Reduce the number of sex partners to minimize the risk of HIV infection.

Always use a condom from start to finish during any type of sex (vaginal, anal, and oral). Use latex condoms rather than natural membrane condoms. If used properly, latex condoms offer greater protection against sexually transmitted disease agents, including HIV.

Use only water-based lubricants. Do not use saliva or oil-based lubricants such as petroleum jelly or vegetable shortening. We do not recommend using spermacides because of the occurrence of rashes due to allergies which increases the risk of contracting HIV.

Avoid anal or rough vaginal intercourse. Do not do anything that could tear the skin or moist lining of the genitals, anus, or mouth and cause bleeding.

Condoms should be used even for vigorous oral sex. (i.e.: sharp teeth may cause puncture)

Avoid deep, wet, or "French" kissing with an infected person. Possible trauma to the mouth may occur, which could result in the exchange of blood. It is safe, however, to hug, cuddle, rub, or dry kiss your partner.

Avoid alcohol and illicit drugs. Alcohol and drugs can impair your immune system and your judgment. If you use drugs, do NOT share "injecting drug works." Do NOT share needles, syringes, or cookers.

Do NOT share personal items such as toothbrushes, razors, and devices used during sex which may be contaminated with blood, semen, or vaginal fluids.

If you are infected with HIV or have engaged in sex or needle-sharing behaviors that lead to infection with HIV, do NOT donate blood, plasma, sperm, body organs, or tissues.

TREATMENT OF HIV/AIDS-RELATED ILLNESSES

 Three important facts about treatment for HIV are:

Treatment is available for HIV-infected persons who are asymptomatic, or without symptoms.

There are numerous ongoing clinical trials and treatments.

Prevention of several illnesses affecting persons with HIV infection is possible.

Many new therapies have received approval from the Food and Drug Administration for undergoing clinical trials. Since treatment for asymptomatic HIV infection is now available, early diagnosis of infected persons is vitally important.

*Click the Medication Chart to see the most current drugs available to HIV clients.

Starting Treatment Right Away?

There is debate about how soon to start anti-retroviral therapy (drugs that weaken HIV's ability to reproduce and thus delay, minimize or prevent the virus from damaging your immune system). As with so many complicated treatment decisions, it will help to talk to your health care providers and other PHA's who have faced the same dilemmas.

Some providers and PHA's believe that if you initiate combination anti-retroviral therapy within 12 weeks of infection, you may be able to eradicate HIV from your body right at the start. This has yet to be proven, and most persons are uncertain as to exactly when they become infected.

There is also some emerging medical opinion that if you have been exposed to HIV through a needle stick injury or other occupational exposure, you should initiate combination anti-retroviral therapy within 36 hours of exposure. A number of hospitals have developed protocols on starting treatment after possible occupational exposure.

Reverse Transcriptase Inhibitors

These drugs block the reverse transcriptase enzyme in the replication cycle of HIV. This is an enzyme unique to the virus and not contained within your own body's cell.

There are two classes of reverse transcriptase inhibitors:

The distinction is important because they work in different ways and are used in different combinations.

Nucleoside analogues (NRTIs or nukes) include AZT (zidovudine or Retrovir), ddl (didanosine or Videx), ddC (zalcitabine or HIVID), d4T (stavudine or Zerit) and 3TC (lamivudine or Epivir).

Non-nucleoside reverse transcriptase inhibitors (NNRTIs or non-nukes) include delavirdine (Rescriptor), nevirapine (Viramune) and efavirenz (Sustiva).

Protease inhibitors are a new class of antiretrovirals that interfere with the last stage of HIV replication. They prevent newly formed viruses from being assembled properly by blocking the protease enzyme, resulting in defective copies of HIV which cannot infect other cells.

There are currently four protease inhibitors being used for HIV treatment: saquinavir (Invirase), ritonavir (Norvir), indinavir (Crixivan) and nelfinavir (Viracept).

What are the stages of HIV infection?

There are four stages of HIV disease:

 1. Primary infection - also known as seroconversion - is the time when you first become infected. You may experience transient (few days to weeks) flu-like symptoms;

2. Asymptomatic infection- is the period after seroconversion when you remain healthy without any symptoms of HIV disease. This may last for many years. Although you remain well, the HIV virus continues to grow;

3. Symptomatic infection -occurs as your immune system is becoming weakened by HIV. You may experience symptoms such as fatigue, night sweats, diarrhea, or weight loss;

4. Advanced HIV -disease or AIDS involves severe symptoms such as wasting and opportunistic infections such as CMV retinitis, pneumonia, MAC and other life threatening conditions.

Infections

Secondary Infections:

Mycobacterium avium complex (MAC)
Mycobacterium avium intracellular (MAI)
Tuberculosis (TB)
Pelvic inflammatory disease (PID)
Bacterial pneumonia
Other bacterial infections

Fungal infections:

Candidiasis (thrush or yeast infections)
Cryptococcosis
Histoplasmosis
Pneumocystis carinii pneumonia (PCP)

Protozoal infections:

Toxoplasmosis
Microsporidiosis
Cryptosporidiosis and isosporiasis

Viral infections:

Cytomegalovirus (CMV)
Herpes simplex virus
Progressive multifocal leukoencephalopathy (PML)
Other viral infections
 

Other AIDS/HIV-related conditions:

Kaposi's sarcoma (KS)
Cervical dysplasia and cancer
Lymphoma
Peripheral neuropathy
AIDS dementia complex (ADC)
Skin problems

Sexually transmitted diseases (STDs):

Chlamydia
Gonorrhea
Syphilis
Genital herpes
Genital warts
Scabies
 

Constitutional symptoms:

(your first signs of HIV infection, are similar to the flu)

Fever
Night sweats
Fatigue
Pain
Diarrhea
Weight loss
Wasting