What is a potential effect of untreated HIV infection?

Untreated HIV infection can lead to a higher risk of opportunistic infections due to the virus's impact on the immune system. HIV primarily attacks CD4+ T cells, which play a crucial role in the body’s ability to ward off infections. Over time, as the virus progressively weakens the immune system, individuals become increasingly susceptible to infections that typically would not cause significant illness in someone with a healthy immune system. These infections are referred to as opportunistic infections because they take advantage of the weakened state of the immune system.

For example, common opportunistic infections include pneumocystis pneumonia, tuberculosis, and certain types of cancers, such as Kaposi's sarcoma. The progression of HIV to AIDS is characterized by the development of these infections, highlighting the importance of early diagnosis and treatment to maintain immune function and prevent such complications.

The other choices do not accurately reflect the consequences of untreated HIV. Improved immune function, a slower aging process, and increased energy levels are not associated with untreated infection; in fact, the opposite is true, as untreated HIV leads to immune decline, potentially accelerated aging, and decreased energy over time.