HIV Infection and AIDS2 by benbenzhou


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									                                                            The Basics of
                                         HIV Infection and AIDS
INTRODUCTION                                                             HOW HIV IS and IS NOT TRANSMITTED
The world first became aware of the disease now known as                 HIV is primarily found in the blood, semen, or vaginal fluid of an
Acquired Immune Deficiency Syndrome (AIDS) in 1981. Since                infected person and is transmitted in three main ways:
then it has become a major worldwide epidemic, with
approximately 33 million people worldwide infected with the                   1) Sexual contact (anal, vaginal, or oral) with
human immunodeficiency virus (HIV), the virus that causes AIDS.                  someone infected with HIV.
Globally there were over 6,800 new infections per day in 2007.                2) Sharing needles/syringes with someone
AIDS remains the primary cause of death in Africa.                               infected with HIV.
The Centers for Disease Control and Prevention (CDC) estimates                3) Being exposed (fetus or infant) to HIV before
that about 1 million people in the United States are living with HIV             or during birth or through breast feeding.
or AIDS, about one-quarter of whom are unaware of their                  The most common route of HIV transmission is through
infection. Approximately 56,300 new HIV infections occur every           having unprotected sex with an infected partner. The virus
year in the U.S. The epidemic is growing most rapidly among              can enter the body through the lining of the vagina, vulva, penis,
minority populations: people of color, gay men, women, young             rectum, or mouth during sex.
people and transgender persons are overly represented among
new infections nationally.                                               Infected Blood
                                                                         HIV also can be transmitted through contact with blood infected
At the end of 2007, a cumulative total of 27,592 San Francisco           with HIV. However, since 1985, all donated blood in the U.S. has
residents were diagnosed with AIDS. This comprises 19% of                been tested for HIV. The risk for HIV infection through the
California AIDS cases and three percent of cases reported                transfusion of blood or blood products is therefore extremely low.
nationally. At the end of 2006, San Francisco ranked third in the
cumulative number of AIDS cases (behind New York City and Los            Contaminated Needles
Angeles), and seventh overall in AIDS incidence among                    HIV is frequently spread among injection drug users (IDUs) by the
metropolitan areas nationwide. The number of persons living with         sharing of needles or syringes contaminated with very small
HIV/AIDS continues to increase and there are now more people             quantities of blood from someone infected with the virus. IDUs
living with AIDS in San Francisco than ever before. All major            may share injection equipment frequently and without sterilization,
HIV/AIDS co-morbidities also converge on the epicenters in San           putting them at risk for acquiring and transmitting HIV.
Francisco: the Castro and the Tenderloin. In San Francisco HIV           It is rare, however, for HIV to be transmitted to or from a health
infection is still most likely to be occurring among men who have        care worker by accidental sticks with contaminated needles or
sex with men (MSM), predominantly of white race; and MSM who             other medical instruments.
also inject drugs.
                                                                         As of December 2001, occupational exposure to HIV has resulted
                                                                         in 57 documented cases of HIV seroconversion among health
WHAT IS HIV?                                                             care workers in the U.S.
HIV, the human immunodeficiency virus, is the virus that causes
AIDS. HIV is a retrovirus that attacks the body’s natural immune         Mother-to-Child (Perinatal) Transmission
system. By finding and killing or damaging certain types of cells        Women can transmit HIV to their babies during pregnancy or
that the immune system must have to fight disease, HIV                   birth. HIV also can be spread to babies through the breast milk of
progressively destroys the body's ability to fight certain infections,   mothers infected with the virus. Approximately one-quarter to
cancers and diseases. The CD4+ T-lymphocyte (“CD4 cell” or “T-           one-third of all untreated pregnant women infected with HIV will
cell”) is the major component of the immune system that is               pass the infection to their babies. Certain drugs given during
infected by HIV. As HIV disease progresses, it slowly wears              pregnancy or delivery can significantly reduce the chances that a
down the immune system.                                                  baby will get infected with HIV. Perinatal transmission of HIV has
                                                                         been almost eradicated in the U.S. due to appropriate screening
                                                                         efforts and treatment.

                                                                         Casual Contact
                                                                         HIV is a fragile virus that cannot live for very long outside the
                                                                         body. As a result, the virus is not transmitted through day-to-
                                                                         day activities like shaking hands, hugging or a casual kiss. HIV
                                                                         is not spread through casual contact such as toilet seats, drinking
                                                                         fountains, doorknobs, dishes, drinking glasses, food, or pets.
                                                                         HIV is not transmitted by biting insects such as mosquitoes or
                               The HIV virion
                                 HIV Medicine 2006                      bedbugs.
The Basics of HIV Infection and AIDS                                                                                                  Page 1
Pacific AIDS Education and Training Center – JANUARY 2009
Saliva, Tears and Sweat                                                 The length of time can be affected by age, genetics, drugs and
Although very low quantities of HIV have been found in saliva and       alcohol, exercise, and previous and existing co-infections.
tears of infected people, there is no evidence that contact with        Even during the asymptomatic period, HIV is actively multiplying,
saliva, tears, or sweat has ever resulted in transmission of HIV.       infecting, and killing cells of the immune system. The virus can
Laboratory studies have shown that saliva has natural properties        also hide within infected cells and lay dormant. The most obvious
that limit the power of HIV to infect, and the amount of virus in       effect of HIV infection is a decline in the number of CD4+ T-cells
saliva appears to be very low. The lining of the mouth, however,        found in the blood. The virus slowly disables or destroys these
can be infected by HIV, and instances of HIV transmission               cells without causing symptoms.
through oral intercourse have been reported.
                                                                        As the immune system worsens, a variety of complications start
Sexually Transmitted Infections (STIs)                                  to take over. For many people, the first signs of infection are large
Co-infection with sexually transmitted infections such as syphilis,     lymph nodes or "swollen glands" that may be enlarged for more
genital herpes, Chlamydia, or gonorrhea directly increases the          than three months. Other symptoms often experienced months to
risk of transmitting HIV.                                               years before the onset of AIDS may include:
                                                                             Lack of energy
DIAGNOSIS                                                                    Weight loss
                                                                             Frequent fevers and sweats
Early HIV infection often causes no symptoms. Diagnosis is                   Persistent or frequent yeast infections (oral or vaginal)
made by serologic testing for detection of antibodies to HIV. The            Persistent skin rashes or flaky skin
standard is a rapid or conventional (EIA; ELISA) screening test              Pelvic inflammatory disease in women that does not
followed by a confirmatory test (Western Blot). Diagnosis may                 respond to treatment
also be established by obtaining a quantitative HIV RNA PCR                  Short-term memory loss
(viral load) test.
                                                                        Some people develop frequent and severe herpes infections that
HIV antibodies generally develop within two weeks to three              cause mouth, genital, or anal sores, or a painful nerve disease
months from exposure. If a high-risk patient has a negative             called shingles.
conventional or rapid screening test, repeat testing should be
considered at a later date, when antibodies to HIV are more likely      WHAT IS AIDS?
to have developed. Virtually all patients seroconvert within six
months. Screening for the presence of HIV genetic material can          Acquired Immune Deficiency Syndrome, or AIDS, is the final,
determine whether a patient has been recently infected (acute           most advanced stage of HIV infection. It can take years for a
infection). Direct screening of HIV is extremely critical in order to   person infected with HIV, even without treatment, to reach this
prevent transmission of HIV from recently infected individuals.         stage. AIDS is diagnosed when the immune system is severely
                                                                        weakened to the point at which the body has a difficult time
Early testing is also an opportunity to alert patients to avoid
                                                                        fighting infections.
high-risk behaviors that could spread the virus to others.
                                                                        The CDC defines an HIV-positive person with a CD4 cell count of
                                                                        fewer than 200 CD4+ T-cells per cubic millimeter of blood as
EARLY HIV INFECTION                                                     having AIDS. (Healthy adults usually have CD4+ T-cell counts in
Acute Infection                                                         the range of 500-1500 cells/mm3). In addition, the definition of
Many people will not have any symptoms when first infected with         AIDS includes over 20 clinical conditions that affect people with
HIV. Within a month or two after exposure to the virus, a flu-like      advanced HIV disease. Most of these conditions are opportunistic
illness develops in 40-90% of patients with symptoms including:         infections that generally do not affect healthy people. In people
                                                                        with AIDS, these infections are often severe and sometimes fatal
      Fever                    Headache                               because the immune system is so ravaged by HIV that the body
      Adenopathy               Diarrhea                               cannot fight off certain bacteria, viruses, fungi, parasites, and
      Pharyngitis              Nausea & vomiting                      other microbes.
      Rash                     Tiredness
                                                                        Symptoms of opportunistic infections common in people with
These symptoms usually disappear within two to four weeks and           AIDS may include:
are often mistaken for those of another viral infection. During this
period people are very infectious, HIV is present in large                     Coughing and shortness of breath
quantities (high viral load), and CD4+ T-cell counts are low.                  Seizures and lack of coordination
                                                                               Difficult or painful swallowing
Asymptomatic/Clinical Latency Period                                           Mental symptoms such as confusion and forgetfulness
More persistent or severe symptoms may not appear for 10 years                 Severe and persistent diarrhea
or more after HIV first enters the body in adults. This period of              Fever
"asymptomatic" infection or “clinical latency” is the longest stage            Vision loss
of chronic infection and varies greatly in each individual. Some               Nausea, abdominal cramps, and vomiting
people may begin to have symptoms within a few months, while                   Weight loss and extreme fatigue
others may be symptom-free for more than 10 years.                             Severe headaches
                                                                               Coma
The Basics of HIV Infection and AIDS                                                                                                   Page 2
Pacific AIDS Education and Training Center – JANUARY 2009
  What are the AIDS-defining                  People with AIDS are also particularly prone to developing various cancers, especially those
         conditions?                          caused by viruses such as Kaposi's sarcoma and cervical cancer, or cancers of the immune
                                              system known as lymphomas. These cancers are usually more aggressive and difficult to treat
  Candidiasis of brochi, trachea
                                              in people with AIDS. Signs of Kaposi's sarcoma in light-skinned people are round brown,
   or lungs
                                              reddish, or purple spots that develop in the skin or in the mouth. In dark-skinned people, the
  Candidiasis, esophageal
                                              spots are more pigmented.
  Cervical cancer (invasive)
  Coccidioidomycosis,                        During the course of HIV infection, most people experience a gradual decline in the number of
   disseminated or                            CD4+ T cells, although some may have abrupt and dramatic drops in their CD4+ T-cell counts.
   extrapulmonary                             A person with CD4+ T cells above 200 may experience some of the early symptoms of HIV
  Cryptococcosis,                            disease. Others may have no symptoms even though their CD4+ T-cell count is below 200.
  Cryptosporidiosis, chronic                 TREATMENT
   intestinal (> one month
   duration)                                  There is no cure for AIDS or vaccine against HIV. HIV treatment includes antiretroviral
  Cytomegalovirus disease                    medications to prolong life and improve the quality of life, and medications administered for
   (other than liver, spleen or               primary and secondary prophylaxis of HIV-related opportunistic infections.
   nodes)                                     There are now over 20 FDA-approved antiretroviral medications for HIV treatment. Antiretroviral
  Encephalopathy (HIV-related)               mediations are used to control viral reproduction and slow the progression of HIV disease. The
  Herpes simplex (severe                     U.S. Department of Health and Human Services (DHHS) HIV treatment guidelines recommend
   infection)                                 a combination treatment to effectively suppress the virus. Use of multiple drugs (three or more)
  Histoplasmosis, disseminated               used in combination is referred to as Highly Active Antiretroviral Therapy, or HAART. HAART is
   or extrapulmonary                          used both by people who are newly infected with HIV as well as people with AIDS, and is the
  Isosporiasis, chronic intestinal           current standard of care for HIV/AIDS treatment in the community. HAART does not cure
   (> one month duration)                     AIDS and antiretroviral medications do not kill HIV.
  Kaposi's sarcoma                           Although the DHHS HIV treatment guidelines recommend “preferred” HAART regimens, each
  Lymphoma, Burkitt’s                        should be tailored to the needs of the individual patient. The decision to begin HAART should be
  Lymphoma, immunoblastic                    based on:
  Lymphoma, primary, of brain
  Mycobacterium avium complex                     1.   Symptoms of advanced HIV disease.
  Mycobacterium tuberculosis,                     2.   CD4+ T-cell count.
   any site (pulmonary or                          3.   HIV viral load.
   extrapulmonary)                            HAART should be considered for HIV-positive patients who have:
  Pneumocystis carinii/jiroveci
                                                    Severe symptoms of HIV infections or a diagnosis of AIDS.
   pneumonia (PCP)
                                                    CD4+ T-cell count of 350 cells/mm3 or less (treatment should always be offered to
  Pneumonia (recurrent)
                                                     patients with a CD4+ T-cell count of 200 cells/mm3 or less).
  Progressive multifocal
                                                    HIV viral load of 100,000 copies/mL or more.
  Salmonella septicemia                      HIV can become resistant to any of the HAART medications, and adherence to anti-HIV
   (recurrent)                                therapies in the range of 90-95% is required for treatment success. Missing medication doses is
  Toxoplasmosis of the brain                 the most common reason for treatment failure and developing drug resistance. A thorough
  Wasting syndrome                           assessment of patient willingness, readiness and ability to begin treatment is vital.

Other factors to consider when determining an anti-HIV medication regimen include:
      Drug resistance testing results                                           Ability to access medications
      Number of pills and how often they must be taken                          Drug interactions with other medications
      Food requirements                                                         Other diseases and conditions.

Side Effects
Despite the benefits of HAART, there are side effects associated with the use of antiretroviral medications that can be severe or even
life threatening. Some possible side effects of antiretroviral therapy include:
      nausea, vomiting, diarrhea, and                   liver problems (hepatotoxicity)            decreased bone density
       other gastrointestinal symptoms                   diabetes (hyperglycemia)                   pancreatitis
      fatigue                                           abnormal fat distribution                  nerve problems
      headache                                           (lipodystrophy syndrome)
      skin rash                                         high cholesterol (hyperlipidemia)
Patients on HAART should be monitored for drug toxicity and encouraged to report any adverse effect symptoms immediately, since
side effects that may seem minor such as fever, nausea, and fatigue can be indicators of a more serious problem.

The Basics of HIV Infection and AIDS                                                                                                    Page 3
Pacific AIDS Education and Training Center – JANUARY 2009
                                                                                       REFERENCES AND RESOURCES
                                                                             This handout includes material adapted from:
There are high rates of HIV infection among patients with a dual
diagnosis of severe mental illness and substance abuse disorder. HIV         2007 AIDS Epidemic Update, UNAIDS/WHO
infection also increases the risk of developing mental health and  
substance abuse disorders. Some studies also suggest a strong link           2007 HIV/AIDS Epidemiology Report, San Francisco
between dual diagnosis and the risk of acquiring HIV. Major                  Department of Public Health
depression is the most frequently occurring psychiatric disorder in
patients with HIV. Pre-existing mental conditions may also impact a          A Guide to Primary Care for People with HIV/AIDS
patient’s ability to cope with a new HIV diagnosis.                
Clinicians and service provides should develop and maintain skills to        HRSA HIV/AIDS Bureau, May 2004.
                                                                             Practical information for common questions that arise in the
address the mental health and substance use disorders commonly               care of patients with HIV infection.
associated with HIV, and the factors that may trigger distress in
persons living with HIV disease and AIDS. Co-morbid conditions               AIDSinfo
should be treated as soon as possible; drug use and HIV should be  
treated aggressively when possible.                                          Comprehensive resource for up-to-date HIV/AIDS
                                                                             information, clinical trials, and the most current, federally
Clinicians should also be aware of common drug interactions in               approved guidelines for treatment and prevention.
multiply-diagnosed patients.                                                 AIDS InfoNet
HIV PREVENTION                                                               HIV/AIDS treatment information provided in the form of
                                                                             single-topic fact sheets.
No vaccine for HIV is available and the only way to prevent infection by
the virus is to avoid behaviors associated with risk of infection, such as   Basic HIV/AIDS Information from the Centers for
                                                                             Disease Control and Prevention (CDC)
sharing needles or having unprotected sex. Ongoing HIV prevention
education is essential, and the key messages are:
                                                                             CDC Fact Sheet: HIV and Its Transmission
   No risky activity is safe; and,                                
   Exposure to bloody body fluids and semen should be
    avoided.                                                                 Clinical Guidelines: HIV and Mental Health and
                                                                             HIV and Substance Use
Prevention efforts for both people not exposed (HIV-) and for those
exposed (HIV+) are essential for reducing new infections. CDC’s              New York State Department of Health AIDS Institute
“Advancing HIV Prevention” initiative emphasizes four strategies:            Clinical Manual for Management of the HIV-Infected
  1. Making HIV testing a routine part of medical care.                      Adult
  2. Implementing new models for diagnosing HIV infection outside            AIDS Education and Training Centers National Resource
     medical settings (i.e., rapid testing).                                 Center, 2006.
  3. Preventing new infections by working with people diagnosed with         HIV and Its Treatment: What You Should Know –
     HIV and their partners (“prevention with positives”).                   Health Information for Patients
  4. Further decreasing mother-to-child transmission.                        Fact sheets from AIDSinfo on testing, medications,
                                                                             treatment adherence, pregnancy, and prevention.
Clinicians providing medical care to HIV-infected persons can play a
key role in helping their patients reduce risk behaviors and maintain        ochure_en.pdf
safer practices. Clinicians can affect patients' risks for
                                                                             HIV InSite Knowledge Base (UCSF online textbook)
transmission of HIV to others by:                                  
   Screening for HIV transmission risk behaviors.
                                                                             NIH Fact Sheet: HIV Infection and AIDS
   Communicating prevention messages.                             
   Discussing sexual and drug-use behavior.                                 Overview of HIV infection, including transmission,
                                                                             symptoms, diagnosis, treatment, and prevention of
   Positively reinforcing changes to safer behavior.                        HIV/AIDS.
   Referring patients for specialty services such as substance
      abuse treatment.
   Facilitating partner notification, counseling, and testing.
   Identifying and treating other STDs.
          Contact your local Pacific AIDS
          Education and Training Center:                                          National HIV Telephone Consultation Service
                                                                                  (Warmline): 1-800-933-3413
         http://familymedicine.medschool.                                         National Clinicians' Post-Exposure Prophylaxis
                                                         Hotline (PEPline): 1-888-HIV-4911
The Basics of HIV Infection and AIDS
                                                                                  Perinatal HIV Hotline:                               Page 4
Pacific AIDS Education and Training Center – JANUARY 2009                         1-888- 448-8765

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