Explain Opportunistic infections.

Opportunistic infections (OIs) are infections caused by pathogens that typically do not cause disease in individuals with a healthy immune system but take advantage of weakened immunity, often seen in conditions such as HIV/AIDS, immunosuppressive therapy, or certain medical treatments. These infections pose a significant threat to individuals with compromised immune systems.

In the context of HIV/AIDS, as the virus progressively weakens the immune system, individuals become susceptible to opportunistic infections. Common opportunistic infections include Pneumocystis pneumonia (PCP), Candidiasis, Tuberculosis, Cytomegalovirus (CMV), and various fungal, bacterial, and viral infections.

The term "opportunistic" reflects the ability of these pathogens to seize the opportunity provided by a weakened immune system to cause infections. Opportunistic infections often serve as indicators of the severity of immunosuppression and the progression of diseases like AIDS. Managing and preventing these infections is a critical aspect of healthcare for individuals with compromised immune systems, involving a combination of antiretroviral therapy (ART), prophylactic medications, and vigilant monitoring of immune function.