What serious illness can be caused by listeria infection?

Listeriosis is the correct answer as it specifically refers to the illness caused by the bacterium Listeria monocytogenes. This infection can lead to serious complications, particularly in vulnerable populations such as pregnant women, neonates, elderly individuals, and those with weakened immune systems. The symptoms of listeriosis can be mild in healthy adults but can escalate to life-threatening conditions like meningitis or septicemia in those at higher risk.

Meningitis, while a potential complication of listeriosis, is not the primary illness associated with a Listeria infection. Encephalitis is another serious condition but is distinct from listeriosis itself and is typically caused by other infectious agents. Appendicitis, likewise, is a separate condition that involves inflammation of the appendix and is unrelated to listeria infection. Understanding that listeriosis is the specific disease caused by the Listeria bacteria provides clarity on the range of potential health risks it poses.