Defining the neurotoxin derived illness chronic ciguatera using markers of chronic systemic inflammatory disturbances: a case/control study.

BACKGROUND: Ciguatoxins are extremely potent neurotoxins, produced by tropical marine dinoflagellates, that persistently enter into our food web. Over 100,000 people annually experience acute ciguatera poisoning from consuming toxic fish. Roughly 5% of these victims will develop chronic ciguatera (CC), a widespread, multisymptom, multisystem, chronic illness that can last tens of years. CC is marked by disproportionate disability and non-specific refractory symptoms such as fatigue, cognitive deficits and pain, and is suggestive of other illnesses. Its unknown pathophysiology makes both diagnosis and treatment difficult.

OBJECTIVES: We wanted to compare objective parameters of visual contrast sensitivity testing, measures of innate immune response and genetic markers in cases to controls to assess the potential for the presence of persistent inflammatory parameters that are demonstrated in other biotoxin associated illnesses at a single specialty clinic.

METHODS: Using 59 CC cases and 59 controls we present in retrospective review, in all cases, abnormalities in immune responses paralleling the chronic systemic inflammatory response syndrome seen in several other chronic diseases.

RESULTS: This study defines a preliminary case definition using medical history, total symptoms, visual contrast sensitivity, HLA DR genotype analysis, reduction of regulatory neuropeptides VIP and MSH, and multiple measures of inflammatory immune response, especially C4a and TGFβ1, thereby providing a basis for identification and targeted therapy.

CONCLUSIONS: CC provides a model for chronic human illness associated with initiation of inflammatory responses by biologically produced neurotoxins.