Direct and indirect affection of the central nervous system by Fasciola infection

Fascioliasis is a worldwide, zoonotic disease caused by the liver trematodes Fasciola hepatica and Fasciola gigantica. Neurological fascioliasis has been widely reported in all continents, affecting both sexes and all ages. Two types of records related to two physiopathogenic mechanisms may be distinguished: cases in which the neurological symptoms are due to direct effects of a migrating juvenile present in the brain or neighboring organ and with cerebral lesions suggesting migration through the brain; and cases with neurological symptoms due to indirect immuno-allergic and toxic effects at distance from flukes in the liver. Neurological manifestations include minor symptoms, mainly cephalalgias, and major symptoms which are nonspecific, extremely diverse, varying from one patient to another and even within the same patient, and comprising meningeal manifestations and impressive neurological manifestations. The puzzling neurological polymorphism leads to confusion with cerebral tumors, multiple sclerosis, lesions of the brainstem, or cerebro-meningeal hemorrhages. Only blood eosinophilia and information on infection source guide toward correct diagnosis by appropriate coprological and/or serological techniques. Although neurological patients usually recover after fasciolicide treatment or surgical worm extraction, sequelae, which are sometimes important, remain in several patients. The need to include possible neurological complications within the general frame of fascioliasis becomes evident.