ABSTRACT

Avariety of worms generally designated as helminths are associated with disease of the eye and its adnexae, some frequently, others rarely. Parasitism, which describes the relationship between the worm and its host, is defined as a state of symbiosis in which the symbiont benefits from the association and the host is harmed in some way. This is in contrast to commensalism, which refers to a symbiotic state wherein one symbiont, the commensal, benefits without detriment to the host, and to mutualism, in which both host and symbiont benefit from the association. A number of helminths responsible for human disease are obligate parasites in that humans are essential if the worm is to complete its life cycle (11). In other instances, however, human infection is accidental, the usual or elective hosts belonging to other species of the animal kingdom.