HIV infection weakens your immune system, making you highly susceptible to a large number of bacterial, viral, fungal and parasitic infections. You may also be vulnerable to certain types of cancers. But treatment with anti-retroviral drugs has markedly decreased the number of opportunistic infections and cancers affecting people with HIV. It's now more likely these infections will occur in people who have not had treatment.
Bacterial infections
- Bacterial pneumonia. Dozens of types of bacteria can cause bacterial pneumonia, which may develop on its own or after you've had an upper respiratory infection such as a cold or the flu.
- Mycobacterium avium complex (MAC). This infection is caused by a group of mycobacteria referred to by a single name MAC. The mycobacteria normally cause an infection of the respiratory tract. But if you have advanced HIV infection and your CD4 lymphocyte count is less than 50, you're more likely to develop a systemic infection that can affect almost any internal organ, including your bone marrow, liver or spleen. MAC causes nonspecific symptoms such as fever, night sweats, weight loss, stomach pain and diarrhea.
- Tuberculosis (TB). In resource-poor nations, TB is the most common opportunistic infection associated with HIV and a leading cause of death among people living with AIDS. Millions of people are currently infected with both HIV and tuberculosis, and many experts consider the two diseases twin epidemics. That's because HIV/AIDS and TB have a deadly symbiotic relationship, in which each fuels the progress of the other. Having HIV makes you more susceptible to TB and far more likely to progress from dormant to active HIV infection. At the same time, TB increases the rate at which the AIDS virus replicates. What's more, TB often strikes people with HIV years before other problems associated with HIV develop. One of the first indications of HIV infection may be the sudden onset of TB often in a site outside the lungs. If you're HIV-positive, you should have a simple skin test for TB early in your medical care. If the test is positive, you'll also need a chest X-ray and other appropriate tests to make sure you don't have an active infection. If your TB isn't active, there are treatments to prevent it from becoming active. TB is more worrisome than many other opportunistic infections because it's highly contagious. Multidrug-resistant tuberculosis, in which the disease resists treatment with traditional antibiotics, is of particular concern to people with HIV/AIDS.
- Salmonellosis. You contract this bacterial infection from contaminated food or water. Symptoms include severe diarrhea, fever, chills, abdominal pain and, occasionally, vomiting. Although anyone exposed to salmonella bacteria can become sick, salmonellosis is far more common in people who are HIV-positive. You can reduce your risk by washing your hands carefully after handling food and animals and by cooking meat and eggs thoroughly.
- Bacillary angiomatosis. This infection, caused by Bartonella henselae bacteria, first appears as purplish to bright red patches on your skin. It often resembles Kaposi's sarcoma, but it can cause disease in other parts of your body, including your liver and spleen.
