Parasites and Neurological Disease; Overview

Parasitic diseases of the central nervous system (CNS) contribute extensively to morbidity and mortality in the developing world and in industrialized nations with a high immigrant influx of people from endemic areas. The variable nature of the immunological reaction of the host against parasites and the many pathological lesions that these pathogens may cause in the human brain make these conditions highly pleomorphic. Parasitic invasion of the CNS may cause encephalitis, meningitis, space-occupying brain lesions, stroke, and myelopathy. Although these conditions have well-defined causal agents, their diagnosis could be a challenge, as histological demonstration of the parasite is not possible in most cases. Moreover, clinical manifestations are nonspecific, neuroimaging findings are most often not pathognomonic, and immune diagnostic tests are faced with problems related to poor sensitivity or specificity. Precise knowledge of the spectrum of parasitic diseases of the CNS is important to direct prompt therapy to reduce the risk of further brain damage. Unfortunately, therapy of most parasitic diseases of the CNS is based on results from uncontrolled trials.