What is HIV/AIDS?

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• How HIV is Spread
• HIV Symptoms
• Diagnosing AIDS
• Additional Information on What is HIV/AIDS?

The human immunodeficiency virus (HIV) causes AIDS, the acquired immunodeficiency syndrome. There are different types of HIV. Most people have the HIV-1 strain (type), but there are many strains. A person can become infected with more than one strain. HIV attacks the body's immune system (natural defense system against disease) by destroying one type of blood cell (CD4 cells) that helps the body fight off and destroy germs.

CD4 cells belong to a group of blood cells called T-cells that also help the body fight disease. In the body, HIV gets into these cells, makes copies of itself, and kills the healthy cells. Then the body can't fight germs anymore. When HIV takes over enough CD4 cells or causes serious infections that don't normally make a healthy person sick, a person then has AIDS. The progression from HIV to AIDS is different for everyone — some people live for 10 years or more with HIV without developing AIDS, and others get AIDS faster.

How HIV is Spread

HIV is spread through some of the body's fluids. HIV is in:

• blood
• semen
• vaginal fluids
• breast milk
• some body fluids sometimes handled by health care workers (fluids surrounding the brain and spinal cord, bone joints, and around an unborn baby)

HIV is passed from one person to another by:

• having sex (vaginal, anal, or oral) with a person who has HIV
• sharing needles with someone who has HIV, such as during injection drug use
• pregnancy, birth, or breastfeeding if a mother has HIV
• getting transfusions of blood that has HIV, which is rare in the United States

HIV is NOT spread by:

• sitting on toilet seats
• hugging, handshakes, or closed-mouth kissing (there is a small chance of getting HIV from open-mouthed or "French" kissing if there's contact with blood)
• sharing food or drinks
• donating blood
• working with or being around someone with HIV
• using phones
• getting bug bites
• tears
• swimming in pools

HIV Symptoms

Many people have no symptoms when they first get HIV — some have no symptoms for years. It varies from person to person. But some people get a flu-like illness within a month or two after first getting HIV. The flu-like symptoms — fever, headache, fatigue (being a lot more tired than usual, and all the time), swollen lymph nodes (glands in the neck and groin) — often go away within a week to a month. Even if there are no symptoms, HIV can still be passed to another person.

It's important to remember that HIV is active inside your body, even when you don't have symptoms. As the HIV infection spreads throughout your body, you'll start to feel sick. For many people, the first symptom they notice is large lymph nodes (swollen glands) that may be enlarged for more than three months. Other symptoms that follow may include:

• being very tired (fatigue)
• quick weight loss
• fevers
• night sweats
• headache
• nausea
• vomiting
• diarrhea
• sore muscles
• mouth, genital, or anal sores
• sore throat
• rash

There are also other health problems that are more common, serious, and harder to treat in women with HIV:

• vaginal yeast infections
• other vaginal infections such as bacterial vaginosis and sexually transmitted diseases (STDs) like gonorrhea, chlamydia, and trichomoniasis
• pelvic inflammatory disease (PID) or infection of a woman's reproductive organs
• menstrual cycle changes, like not having periods or having heavy and constant bleeding
• human papillomavirus (HPV) infections that cause genital warts and can lead to cervical cancer

As the immune system continues to weaken, other diseases and infections, called opportunistic infections (OIs), can develop that affect your eyes, digestive system, kidneys, lungs, skin, and brain.

Diagnosing AIDS

The Centers for Disease Control and Prevention (CDC) defines AIDS as being infected with HIV and

• having less than 200 CD4 cells per cubic millimeter of blood. Healthy adults have CD4 and T cell counts of 1,000 or more.
  
  OR

• having at least one of the health problems common in people with AIDS, some of which are called opportunistic infections (OIs). Examples of OIs include wasting syndrome, recurrent pneumonia, or invasive cervical cancer. People who have AIDS can have severe OIs, which can be fatal because their bodies can't fight them off.

Listed below are health problems common in people with AIDS:

• coughing and shortness of breath
• seizures
• lack of coordination
• hard or painful to swallow
• hard to think and remember things
• severe and persistent diarrhea
• fever
• loss of vision
• nausea, stomach cramps, and vomiting
• weight loss
• feeling very tired all the time
• severe headaches
• diarrhea
• coma
• pneumonia
• cancers of the skin or immune system

Additional Information on What is HIV/AIDS?:

Publications

1.   Basic Information - This web page describes what the HIV virus looks like, its history, how it is transmitted, symptoms of HIV infection, where to get tested, and other basic information about the virus.

   http://www.cdc.gov/hiv/topics/basic/

2.   HIV and AIDS: Are You at Risk? - This brochure explains what HIV/AIDS is, how to know if you have it, what testing is done, and how to protect yourself from being infected.

   http://www.cdc.gov/hiv/resources/brochures/at-risk.htm

3.   HIV and Its Transmission - This publication discusses how HIV is transmitted. It examines transmission rates in different environments such as business and home settings and discusses the effectiveness of condoms.

   http://www.cdc.gov/hiv/resources/factsheets/transmission.htm

4.   HIV Infection and AIDS: An Overview - This fact sheet briefly describes early and advanced (AIDS) symptoms, diagnosis, treatment, prevention and current research on human immunodeficiency virus (HIV) infection. Risky behavior and measures to control the spread of HIV are also discussed.

   http://www.niaid.nih.gov/factsheets/hivinf.htm

5.   HIV Infection In Women - AIDS is the fourth leading cause of death for women aged 25 to 44 in the United States. This fact sheet addresses the special concerns that women with HIV face.

   http://www.niaid.nih.gov/factsheets/womenhiv.htm

6.   How HIV Causes AIDS - This fact sheet contains an overview of the HIV virus, the scope of the HIV epidemic, the life cycle of HIV, the course of HIV infection, NIAID research, and a glossary of terms.

   http://www.niaid.nih.gov/factsheets/howhiv.htm

7.   Questions and Answers (Q&A) - This page contains answers to common questions regarding transmission and prevention, testing, HIV-related hoaxes and rumors, and other general questions about the HIV/AIDS.

   http://www.cdc.gov/hiv/resources/qa/index.htm

8. HIV Infection in Women (Copyright © AAFP) - This publication provides information on HIV and AIDS, how women can get infected with the virus, who is at risk for the infection, how HIV differs between men and women, and precautions that can be taken to prevent contracting this disease.

   http://familydoctor.org/online/famdocen/home/women/reproductive/sti/225.html

9. The Global HIV/AIDS Timeline (Copyright © The Henry J. Kaiser Family Foundation) - The Kaiser Family Foundation has provided an interactive timeline to use in learning about the spread of HIV/AIDS, advancements in research, and statistics on how many people have been affected at each five year mark over the past twenty-five years.

   http://www.kff.org/hivaids/timeline/index.cfm

10.   The HIV/AIDS Epidemic in the United States (Copyright © The Henry J. Kaiser Family Foundation) - This publication gives information on the prevalence and impact of HIV/AIDS in the United States.

    http://www.kff.org/hivaids/upload/3029-071.pdf

Organizations

1.   AIDS.Gov
2.   AIDSInfo
3.   CDC-INFO
4.   Division of Acquired Immunodeficiency Syndrome(DAIDS), NIAID, NIH, HHS
5.   Division of HIV/AIDS Prevention, NCHSTP, CDC, OPHS, HHS
6.   National Institute of Allergy and Infectious Diseases, NIH, HHS
7. AIDS InfoNet
8. The Well Project

= Indicates Federal Resources

Content last updated January 25, 2008.