The HIV virus actively multiplies, infects and kills cells of the immune system called CD4+T cells, which are the immune system's key infection fighters. As soon as HIV enters the body, it begins to disable or destroy these cells, even when you are not experiencing any symptoms.

HIV is not spread through casual contact such as sharing food, utensils, towels, bedding, swimming pools, telephones or toilet seats. HIV also is not spread by insects, such as mosquitoes or bedbugs.

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HIV can be spread by:

  • Blood transfusions with HIV-infected blood. This is rare since all donated blood is tested for HIV.
  • HIV-contaminated needles.
  • Sexual contact, especially intercourse or anal sex.
  • A mother to child during pregnancy, childbirth or breastfeeding.

In rare instances, HIV can be spread by:

  • A bite by someone infected with HIV
  • Blood from an HIV-infected person entering an open wound
  • Sharing personal hygiene items, such as razors and toothbrushes, with a person infected with HIV

Sexually transmitted diseases such as syphilis, genital herpes, chlamydia or gonorrhea appear to increase the susceptibility of getting HIV during sex with infected partners

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Many people don't have any symptoms when they first become infected with HIV. Some have a flu-like illness, called HIV sero-conversion syndrome, a month or two after exposure to the virus. This illness may cause a variety of symptoms, including:

  • Diarrhea
  • Enlarged liver or spleen
  • Fever
  • Enlarged or swollen lymph nodes
  • Headache
  • Muscle pain
  • Nausea and vomiting
  • Neurologic symptoms
  • Rash on the abdomen, arms and legs and face
  • Sore throat
  • Thrush, a common fungal infection of the mouth caused by Candida, a yeast-like fungus

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Blood tests are the most common way to diagnose HIV. These tests look for antibodies to the virus that the body creates in an attempt to fight the virus.

People exposed to the virus should get tested immediately, although it can take the body anywhere from six weeks to a year to develop antibodies to the virus. Follow-up tests may be needed depending on the initial time of exposure.

Early testing is crucial. If you test positive for the virus, you and your doctor will discuss and develop a treatment plan that can help fight HIV and ward off complications. Early testing also can alert you to avoid high-risk behavior that can spread the virus to others.

Most health care providers offer HIV testing, often with appropriate counseling. Anonymous and free testing also is available. During testing, your doctor will ask about your symptoms, medical history and risk factors, and perform a physical examination.

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At this time, there is no cure for HIV or AIDS, but medications are effective in fighting HIV and its complications. Treatments are designed to reduce HIV in your body, keep your immune system as healthy as possible and decrease the complications you may develop.

You and your doctor will work together to develop a treatment plan that best meets your needs. Three main factors will be considered when designing your treatment plan:

  • Your willingness and readiness to begin therapy
  • The stage of your disease
  • Other health problems

The U.S. Food and Drug Administration (FDA) has approved a number of drugs for treating HIV and AIDS.

It's important that you take your medications exactly as prescribed. This is a crucial part of your treatment success. Our program offers pharmacy services to help you maintain your drug regimen and to answer any questions you may have.

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Reviewed by health care specialists at UCSF Medical Center.