Eosinophilic meningitis caused by Angiostrongylus cantonensis: Report of 17 cases

PURPOSE: To describe two outbreaks of Angiostrongylus cantonensis infection that occurred in Kaohsiung, Taiwan, during 1998 and 1999, and to character ize the source of the outbreaks and the clinical manifestations of the dise ase. SUBJECTS AND METHODS: We performed a retrospective cohort study among Thai laborers with eosinophilic meningitis who ate raw snails (Ampullarium canal iculatus), as well as an environmental surveillance of larvae in snails. RESULTS: We enrolled 17 Thai laborers in whom severe headache and eosinophi lia developed within 4 to 23 days after eating raw snails. Twelve (71%) dev eloped eosinophilic meningitis. Third-stage larvae were found in the cerebr ospinal fluids of 2 patients and in all 12 tested snails. Specific antibodi es to A. cantonensis were detected in serum from 16 of the patients and in cerebrospinal fluid from 5 of the patients. Central nervous system manifest ations included headache n = 17 [100%]), fever (n = 11 [65%]), Brudzinski's sign/stiff neck (n = 11 [65%]), hyperesthesia (n = 3 [18%]), cranial nerve palsy (n = 2 [12%] diplopia (n = 2 [12%]), and ataxia (n = 1 [6%]). Labora tory findings included peripheral eosinophilia (n = 15 [88%]) and cerebrosp inal fluid eosinophilia (n = 12 [71%]); elevated immunoglobulin (Ig) E leve ls (n = 13 [100%]); and transient increases in white blood cell count (n = 7 [41%]) and in serum levels of creatine kinase (n = 7 [41%]), transaminase (n = 3 [ 18%]), and lactate dehydrogenase (n = 2 [12%]). The severity of i llness and eosinophilia were correlated with the number of ingested snails. Meningeal and basal ganglion enhancement was noted on magnetic resonance i maging in several patients. Treatment with mebendazole combined with glucoc orticosteroids appeared to shorten the course of the infection, but not the number of relapses. The eosinophil count fell to normal within 3 months, b ut IgE levels remained elevated for as long as 6 months. All patients recov ered with minimal neurologic sequelae. CONCLUSION: Eosinophilic meningitis caused by A. cantonensis should be cons idered in patients who have headache or central nervous system manifestatio ns after eating raw snails. (C) 2001 by Excerpta Medica, Inc.