INTRODUCTION

AIDS, also known as “acquired immunodeficiency syndrome” was first reported in the United States in 1981 and was soon discovered to be a worldwide epidemic.  The cause of AIDS is a virus called HIV (human immunodeficiency virus).  It works by killing or damaging the cells of the body’s immune system.  By doing this it damages the body’s ability to fight off infections and certain cancers.  People who have AIDS may get life-threatening diseases from microbes such as viruses or bacteria that don’t usually make people sick.  These are called opportunistic infections.

Almost one million cases of AIDS have been reported in the United States since 1981 and as many may be infected with HIV.  It is estimated that one quarter of the people infected with HIV are not aware of their infection.  The epidemic is growing at a faster rate among minority populations and is a leading killer of African-American males ages 25 to 44.  According to the Centers for Disease Control and Prevention (CDC), AIDS affects seven times more African Americans and three times more Hispanics then whites.

WHAT IS AIDS?

AIDS is the name for the most advanced stages of HIV infection.  The CDC developed an official definition and is responsible for tracking the spread of the AIDS in the United States.  The CDC’s definition of AIDS is all HIV-infected people who have fewer then 200 CD4+ T cells per cubic millimeter of blood.  Most healthy adults usually have more then 1,000 CD4+ T cell counts per cubic millimeter of blood.  In addition the CDC’s definition includes 26 clinical conditions that affect people who have advanced HIV disease.  Most of the conditions are opportunistic infections that do not generally affect healthy people.  When a person has AIDS, these opportunistic infections (OI’s) are often severe and can be fatal because the immune system has been severely compromised by HIV.  The body cannot fight off certain bacteria, viruses, fungi, parasites, and other microbes.

Symptoms of opportunistic infections common in people with AIDS include

• • Coughing and shortness of breath
• • Seizures and lack of coordination
• • Difficult or painful swallowing
• • Mental symptoms such as confusion and forgetfulness
• • Severe and persistent diarrhea
• • Fever
• • Vision loss
• • Nausea, abdominal cramps, and vomiting
• • Weight loss and extreme fatigue
• • Severe headaches
• • Coma
  

Children who have AIDS may get the same OI’s as adults and they also may have severe forms of typically common childhood bacterial infections, such as pink eye, ear infections and tonsillitis.

AIDS also causes people to be more prone to developing various cancers such as Kaposi’s sarcoma, cervical cancer and cancers of the immune system known as lymphomas.  These cancers are more difficult to treat in people with AIDS because they can be more aggressive.

Most people experience a gradual decline in the number of CD4+ T cells during the course of HIV infection.  Some people may have sudden and dramatic drops in their CD4+ T cell counts.  Everyone reacts differently to HIV, some people who have CD4+ T cell counts above 200 may experience early symptoms of HIV.  Others may have no symptoms, even if their T cell count is below 200.

There are many people who become so debilitated by the symptoms of AIDS that they are unable to hold a steady job or even do simple household chores.  Other people who have AIDS may have phases where they have a life-threatening illness, followed by phases in which they can function normally.

Small numbers of people who were first infected with HIV 10 or more years ago haven’t developed symptoms of AIDS.  Researchers are trying to determine what factors account for their lack of progression to AIDS.

Some factors they are looking at are:

• • Whether their immune systems have particular characteristics
• • If they were infected with a less aggressive strain of the virus
• • Whether there are genetic factors that may protect them from the effects of HIV.
  

Scientists hope that by understanding the body’s natural method of controlling infection, they may be able to develop protective HIV vaccines.

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