What is the name given to infections that are normally present in the environment but can become life-threatening when the immune system is compromised?

The term given to infections that are typically found in the environment but can turn severe when an individual’s immune system is weakened is known as opportunistic infections. These infections take advantage of a compromised immune defense, which might occur due to various factors such as illness, medications, or genetic conditions.

In healthy individuals, the immune system effectively controls these pathogens, preventing them from causing disease. However, when the immune system is not functioning optimally, these normally harmless microorganisms can proliferate and lead to significant health issues. This phenomenon highlights the importance of understanding how certain infections impact individuals with weakened immune responses, such as those who have conditions like HIV/AIDS, are undergoing chemotherapy, or have other systemic diseases.

The other terms listed describe different types of infections. Acute infections typically have a rapid onset and brief duration, chronic infections persist over a long period, and primary infections refer to initial infections that occur in a previously healthy individual. None of these terms specifically pertain to the opportunistic nature of infections that exploit the vulnerabilities in a weakened immune system.