The major impediment to the thorough study of Ciguatera in human populations has been the lack of definitive diagnostic ability. However, recently an ELISA test was developed which can diagnose Ciguatera qualitatively and quantitatively in human fluids, as well as in contaminated fish tissue. This study proposes to evaluate this new ELISA test in human subjects with the clinical diagnoses of acute and chronic Ciguatera Poisoning. The contaminated fish from exposed subjects, and the blood and urine of exposed and controls, will be examined using the new ELISA. The ELISA performance will be compared to traditional bioassays for the fish testing. In addition, a distinct diagnostic profile will be developed using serial questionnaires, physical examinations, and nerve conduction tests. Ultimately this ELISA test can be used not only in establishing the correct diagnosis of Ciguatera Poisoning, but also in the treatment and clinical prognosis, and in epidemiologic studies of Ciguatera Poisoning in human populations. We hope that this protocol will serve as a model for the study of the effects of other marine toxins on human populations.