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HIV & AIDS Health Center

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HIV/AIDS and Opportunistic Infections

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HIV (human immunodeficiency virus) attacks the body's white blood cells -- specifically a subset called CD4 or helper T cells. This attack allows opportunistic infections to take advantage of a weakened immune system, and can lead to illnesses, cancers, or neurological problems. If you have HIV and develop an opportunistic infection, your HIV infection may have progressed to AIDS (acquired immunodeficiency syndrome). But with careful monitoring, self-care, and treatment, you can prevent many infections and stay healthier if you do develop an infection.

Where HIV Opportunistic Infections Come From

A wide variety of germs can cause HIV opportunistic infections. These include bacteria, viruses, protozoa, or fungi. Even before you have HIV, you have many of these in your body. But a healthy immune system normally keeps them under control. These are examples of other places where you can pick up germs that cause HIV opportunistic infections:

  • Unwashed raw foods
  • Soil or water
  • Contact with animal feces
  • Contact with other people, through unsafe sex or in places where germs are common, such as hospitals, day care centers, or schools
  • Contact with blood through sharing needles or intravenous drugs

Common HIV Opportunistic Infections

Almost any disease can become an HIV opportunistic infection when the immune system is weak. Some are more common than others, though. And some are more likely to occur at certain levels of CD4 counts than others. Here are some of the more common HIV opportunistic infections:

  • Candidiasis (thrush): a fungal infection in the mouth, throat, or vagina.
  • Cryptococcus neoformans (Crypto): a fungus that can lead to meningitis, a serious inflammation of membranes surrounding the brain and spinal cord.
  • Cryptosporidiosis and microsporidiosis: protozoa affecting the gastrointestinal tract.
  • Cytomegalovirus (CMV): a virus that causes eye disease and can lead to blindness. It can also cause severe diarrhea and ulcers.
  • Herpes simplex: viruses that can cause severe genital or cold sores.
  • Mycobacterium avium complex (MAC): a bacterium that can cause fevers, problems with digestion, and serious weight loss.
  • Pneumocystis pneumonia (PCP): a fungus that can cause fatal pneumonia.
  • Progressive multifocal leukoencephalopathy (PML): a virus affecting the brain.
  • Toxoplasmosis (Toxo): a protozoa that sometimes causes encephalitis, an inflammation of the brain.
  • Tuberculosis (TB): a bacterial infection that attacks the lungs and can invade other organs. TB can lead to meningitis at its most severe.

There are some differences between women and men with respect to opportunistic infections. Here are a few of them:

  • Men are eight times more likely to develop a cancer called Kaposi's sarcoma.
  • Women are more likely to develop bacterial pneumonia and herpes simplex infections.
  • Women are also more at risk for certain infections that can lead to cancers of the reproductive system.

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