What type of infection poses a greater risk when a person's immune system is weakened?

Opportunistic infections are those that take advantage of a weakened immune system. When an individual's immune defenses are compromised, whether due to conditions like HIV/AIDS, cancer treatments, or other immune system disorders, they become more susceptible to infections that would not typically cause illness in a healthy person. These infections are often caused by organisms that are normally present in the body or environment, but that can become problematic when the body's defenses are lowered.

In contrast, while viral, bacterial, and fungal infections can also affect individuals with weakened immune systems, they are not specifically categorized as opportunistic. Opportunistic pathogens can include certain bacteria, viruses, and fungi that exploit the lack of immune response. Therefore, the term "opportunistic infection" refers specifically to the risk posed by these pathogens in immunocompromised individuals, highlighting the elevated danger of infections that are reliant on the host's immune status.