Occupational Safety and Health Administration (OSHA) SLC Practice Exam

What characterizes an opportunistic infection?

1. It spreads easily between hosts.

2. It occurs when the body's defenses are weakened.

3. It is caused by the invasion of microorganisms.

4. It is contracted through contaminated surfaces.

The correct answer is: It occurs when the body's defenses are weakened.

An opportunistic infection is specifically characterized by occurring in individuals whose immune systems have been compromised or weakened. This vulnerability allows normally harmless microorganisms, which typically do not cause disease in healthy individuals, to take advantage of the opportunity presented by the weakened defenses. These infections often occur in individuals with conditions such as HIV/AIDS, cancer, or in those taking immunosuppressive medications. Other aspects of the options reflect unrelated characteristics. While an opportunistic infection may be caused by the invasion of microorganisms, this does not distinguish it from other types of infections. Similarly, the spreading of infections between hosts or transmission through contaminated surfaces can apply to various other infections, not just opportunistic ones. Thus, focusing on the weakened state of the immune system is crucial to defining this particular type of infection.