Abstract

Objective: Ciguatera fish poisoning is the most common seafood-toxin disease, annually affecting approximately 50,000 people worldwide. Incidence rates per thousand vary from 97 in the South Pacific to 0.5 in southern Florida, although these estimates are unreliable due to underreporting and sub-optimal surveillance systems. Ciguatera poisoning occurs when fish that feed on ciguatera-toxin producing organisms are consumed by humans. Clinical features of poisoning include acute gastrointestinal upset followed by neurological symptoms such as numbness, weakness, and disruption of temperature sensation that can persist for months after the ingestion. Diagnosis requires astute clinicians familiar with the signs and symptoms of ciguatera poisoning and high clinical suspicion. In the US, Poison Centers often receive calls from the public and clinicians requesting information about ciguatera poisonings and clinical case management of ciguatera cases. As climate change occurs ciguatera is expected to increase in prevalence and expand beyond its current tropical range. Recent literature has shown an increase in ciguatera poisonings in island nations of the Pacific and Caribbean associated with warming El Niño events and higher sea surface temperatures (SST). Increased severe storm frequency in the region may contribute to coral bleaching, developing more suitable habitat for ciguatoxic organisms. The purpose of this study is to identify what climactic variables impact ciguatera poisoning in the United States, where few epidemiologic studies of this disease have been performed. Methods: A longitudinal retrospective cross-sectional analysis will be performed on observational data from the National Poison Data System (NPDS) collected by the American Association of Poison Control Centers (AAPCC). Data from all calls to US Poison Centers regarding cases of ciguatera poisoning from years 2001-2011 were extracted. Weather data for SST, climate variability indices, and severe storm occurrence are available publicly. The data will be analyzed using descriptive statistics and trend analyses. Conditional logistic regression will be performed to characterize the relationship between the weather and climatic variables and ciguatera cases in the US, controlling for key confounders such as yearly fishing production and accounting for appropriate lag structures. Results: In total we identified 1,273 cases of ciguatera in the US in years 2001-2011. Yearly totals range from 74 to 152 cases. Results from descriptive analysis of the location, timing, and severity of these cases standardized by population will be reported, along with associations between ciguatera and SST, regional climate variability indices, and storm frequency in the Caribbean, Gulf of Mexico, and Atlantic basins. Discussion: The results of this study would contribute to and validate literature investigating the effect of climate on ciguatera poisoning. Importantly, it would do so in a population in which this question has not been studied and that would be susceptible to climate-related expansion of the ciguatera endemic range. Quantification of the association of ciguatera with climatic variables combined with climate projections could provide predictions regarding the future prevalence and range of ciguatera in the US. This can inform policy makers in attempts to implement adaptation measures, such as additional education of health professionals and enhanced surveillance, and provide additional information that will be helpful in projecting the potential public health impacts of unmitigated climate change.