Angiostrongylus (Parastrongylus) eosinophilic meningitis.

Angiostrongylus (Parastrongylus) cantonensis is the commonest cause of eosinophilic meningitis in the world. Infective third-stage larvae develop in slugs and snails. Humans are infected primarily in the central nervous system after ingesting an infected intermediate host. Damage by motile worms, inflammatory responses to foreign bodies, and possible toxicity of worm substances work in concert to produce the pathologic and clinical picture of neurologic angiostrongyliasis. This disease manifests itself by headache, paresthesias, generalized weakness, and occasionally visual disturbances and extraocular muscular paralysis. Eosinophilic pleocytosis is the major laboratory finding. Although the diagnosis of neurologic angiostrongyliasis is usually made clinically, serologic methods such as ELISA (enzyme-linked immunosorbent assay) can be helpful. Occasionally, living larvae can be identified histologically in the CSF, eye, or other tissue. There is no specific treatment for this disease. Corticosteroids may be useful to relieve increased intracranial pressure. The role of anthelmintic drugs, such as thiabendazole and ivermectin, is not yet known. The prognosis of neurologic angiostrongyliasis is usually good; however, fatal and chronic cases do occur. Appropriate preparation of food, control of mollusks and planarians, and elimination of rodents are important measures in limiting the further spread of eosinophilic meningitis caused by A. cantonensis.