What infectious disease affects spinal fluid and can lead to severe complications, including hearing problems?

Meningitis is indeed the correct answer as it specifically refers to the inflammation of the protective membranes covering the brain and spinal cord, which affects the spinal fluid. This condition can be caused by various infectious agents, including viruses and bacteria. Meningitis can lead to severe complications, including neurological deficits, and one of the common long-term effects can be hearing loss. This is especially prevalent in cases of bacterial meningitis, where the infection can damage auditory pathways.

Other conditions mentioned, while they affect the nervous system or related structures, do not directly link to the infection of spinal fluid in the same way. Encephalitis refers to inflammation of the brain itself and may have different complications, but it does not specifically denote involvement with spinal fluid. Hydrocephaly relates to the accumulation of cerebrospinal fluid in the brain's ventricles, but it is a distinct condition that does not directly imply infection. Spina bifida is a congenital condition related to the spinal column not closing properly during development and is not an infectious disease at all. Thus, meningitis directly connects with the infection of spinal fluid and the potential for significant complications such as hearing impairment.