Human immunodeficiency virus (HIV) is the sexually transmitted virus that causes acquired immune deficiency syndrome (AIDS). A person gets HIV when an infected person's body fluids (blood, semen, fluids from the vagina or breast milk) enter his or her bloodstream. The virus can enter the blood through linings in the mouth, anus or sex organs (the penis and vagina), or through broken skin. Both men and women can spread HIV. A person with HIV can feel okay and still give the virus to others. Pregnant women with HIV can also pass the virus to their babies.

You cannot get HIV from:

• Touching or hugging someone who has HIV/AIDS
• Public bathrooms or swimming pools
• Sharing cups, utensils, or telephones with someone who has HIV/AIDS
• Bug bites

HIV weakens a person's ability to fight infections and cancer by attacking and destroying a type of white blood cell called a CD4 cell. Because this cell's main function is to fight disease, a low CD4 cell count means greater susceptibility to illnesses. AIDS is the final stage of HIV infection and can take many years to develop.

Symptoms

Some people get flu-like symptoms a month or two after they have been infected. These symptoms often go away within a week to a month. A person can have HIV for many years before feeling ill. As the disease progresses, both women and men may experience yeast infections on the tongue (thrush), and women may develop severe vaginal yeast infections or pelvic inflammatory disease (PID).

Signs that HIV is turning into AIDS include:

• A fever that won't go away
• Sweating while you sleep
• Feeling tired all the time (not from stress or lack of sleep)
• Feeling sick all the time
• Losing weight
• Swollen glands (neck, groin or underarms)

People with AIDS are extremely vulnerable to infection, called AIDS defining illnesses. These include:

• Kaposi's sarcoma, a skin tumor that looks like dark purple blotches.
• Mental changes and headaches due to fungal infections or tumors in the brain and spinal cord.
• Shortness of breath and difficulty breathing due to infections of the lungs.
• Dementia
• Severe malnutrition
• Chronic diarrhea

Diagnosis

The only way to know if you have HIV is to take an HIV blood test. If a person with HIV infection has a CD4 count that drops below 200 or if AIDS defining illnesses appear, that person is considered to have AIDS.

Treatment

There are a variety of treatments that can significantly slow, and in some cases stop altogether, the progression of HIV infection. HIV treatment generally includes a regimen of several drugs. These drugs must be taken at exactly the right time every single day and may produce a range of side effects including diarrhea, nausea, or abdominal distribution of body fat. The virus often mutates, or changes, making the treatments ineffective. If the disease has progressed to AIDS, treatment may also include drugs to combat and prevent certain infections. The majority of HIV patients who receive appropriate treatment do well and live healthy lives for years though some experience a more rapid course towards AIDS.

Prevention

Safe sexual practices will reduce your risk of infection. These include limiting the number of sex partners and correct use of latex condoms every time you have any type of sex (vaginal, anal, or oral). It is also important to use sterile needles when taking drugs or piercing the body for any reason.

Additional information is available from the Centers for Disease Control and Prevention.