A healthy body has CD4 helper lymphocyte cells (CD4 cells). These cells help the immune system function normally and fight off certain kinds of infections. They do this by acting as messengers to other types of immune system cells, telling them to become active and fight against an invading germ.
HIV attaches to these CD4 cells. The virus then infects the cells and uses them as a place to multiply. In doing so, the virus destroys the ability of the infected cells to do their job in the immune system. The body then loses the ability to fight many infections.
When a person with HIV has an extremely low number of CD4 cells or certain rare infections, doctors call this stage of disease AIDS. People who have AIDS are unable to fight off many infections because their immune systems are weakened. They are more likely to get infections like tuberculosis and some rare infections of the lungs (such as certain types of pneumonia), infections of the surface covering of the brain (meningitis), or the brain itself (encephalitis). People who have AIDS tend to keep getting sicker, especially if they are not taking antiviral medications properly.
AIDS can affect every body system. The immune defect caused by having too few CD4 cells also permits some cancers that are stimulated by viral illness to happen — some people with AIDS get forms of lymphoma and a rare tumor of blood vessels in the skin called Kaposi’s sarcoma.
Because AIDS is fatal, it’s important that doctors detect HIV infection as early as possible so a person can take medicine to delay the onset of AIDS.
How Do People Get HIV ?
Thousands of U.S. teens and young adults get infected with HIV each year. HIV can be transmitted from an infected person to another person through body fluids like blood, semen, vaginal fluids, and breast milk.
The virus is spread through things like:
having unprotected oral, vaginal, or anal sex (“unprotected” means not using a condom)
sharing needles, such as needles used to inject drugs, steroids, and other substances, or sharing needles used for tattooing
Other risk factors:
People who have another sexually transmitted disease (STD) (such as syphilis, genital herpes, chlamydia, gonorrhea, or bacterial vaginosis) are at greater risk for getting HIV during sex with infected partners.
If a woman with HIV is pregnant, her newborn baby can catch the virus from her before birth, during the birthing process, or from breastfeeding.
When doctors know a mom-to-be has HIV, they can do things to try to stop the virus from spreading to the baby. That’s why all pregnant women should be tested for HIV so they can begin treatment if necessary.
How Do People Know They Have HIV ?
How long it takes for symptoms of HIV/AIDS to appear varies from person to person. Some people may feel and look healthy for years while they are infected with HIV. It is still possible to infect others with HIV, even if the person with the virus has absolutely no symptoms. You cannot tell simply by looking at someone whether he or she is infected.
When a person’s immune system is overwhelmed by AIDS, he or she might notice:
- extreme weakness or fatigue
- rapid weight loss
- frequent fevers that last for several weeks with no explanation
- heavy sweating at night
- swollen lymph glands
- minor infections that cause skin rashes and mouth, genital, and anal sores
- white spots in the mouth or throat
- chronic diarrhea
- a cough that won’t go away
- trouble remembering things
- in girls, severe vaginal yeast infections that don’t respond to usual treatment