<p>Having HIV/AIDS weakens your body's immune system. It destroys the white blood cells that fight infection. This puts you at risk for opportunistic infections (OIs). OIs are serious infections that take advantage of your weak immune system. These infections are less common and less severe in healthy people.</p> <p>There are many types of OIs:</p> <ul> <li>Bacterial infections, including <a href="https://medlineplus.gov/tuberculosis.html">tuberculosis</a> and a serious related disease, <a href="https://medlineplus.gov/mycobacterialinfections.html">Mycobacterium avium complex</a> (MAC)</li> <li>Viral infections, such as <a href="https://medlineplus.gov/cytomegalovirusinfections.html">cytomegalovirus</a> (CMV) and <a href="https://medlineplus.gov/hepatitisc.html">hepatitis C</a></li> <li>Fungal infections, like <a href="https://medlineplus.gov/yeastinfections.html">yeast infections</a>, cryptococcal meningitis, <a href="https://medlineplus.gov/pneumocystisinfections.html">pneumocystis carinii pneumonia</a> (PCP) and <a href="https://medlineplus.gov/histoplasmosis.html">histoplasmosis</a></li> <li>Parasitic infections, such as crypto (<a href="https://medlineplus.gov/cryptosporidiosis.html">cryptosporidiosis</a>) and toxo (<a href="https://medlineplus.gov/toxoplasmosis.html">toxoplasmosis</a>)</li> </ul> <p>Having HIV/AIDS can make infections harder to treat. People with HIV/AIDS are also more likely to have complications from common illnesses such as the flu.</p> <p>You can help prevent infections by taking your <a href="https://medlineplus.gov/hivaidsmedicines.html">HIV/AIDS medicines</a>. Other things that can help include practicing safe sex, washing your hands well and often, and cooking your food thoroughly.</p>