Which fatal disease is caused by a viral infection that destroys the immune system?

Acquired immune deficiency syndrome, commonly known as AIDS, is the correct answer because it is caused by the Human Immunodeficiency Virus (HIV), which specifically targets and destroys the immune system's CD4 cells, leading to a severe reduction of the body's ability to fight off infections and diseases. This progressive immune deficiency can make an individual highly susceptible to opportunistic infections and certain cancers, ultimately resulting in a fatal condition if left untreated.

Hepatitis B, while a serious viral infection, primarily affects the liver and does not directly destroy the immune system in the same way HIV does. Meningitis can be caused by various pathogens, including bacteria and viruses, but it is characterized by inflammation of the protective membranes covering the brain and spinal cord rather than a systemic destruction of immune system cells. Poliomyelitis, caused by the poliovirus, primarily affects the nervous system and can lead to paralysis, but again, it does not destroy the immune system as HIV does. Thus, AIDS is identified specifically for its connection to a compromised immune system, making it the correct choice.