Portrait épidémiologique de la Ciguatera dans le Pacifique-sud

Authors: Chateau-Degat, Marie-Ludivine
Advisor: Dewailly, ÉricVerreault, René
Abstract: Ciguatera poisoning is an ichtyosarcotoxism found throughout many tropical areas of the world. Even though this intoxication has been known since the 18th century, many epidemiological aspects remain unclear. The main goal of this thesis was to establish the epidemiological portrait of this seafood poisoning in order to improve its management. The first part of this project describes this ichtyosarcotoxism according to its environmental and temporal aspects. The second part addresses clinical aspects of the disease. A global increase of ciguatera incidence has been suggested in the literature. However, results from our retrospective study indicate a relatively constant annual incidence in French Polynesia over the ten years of the study. An analysis of cases grouped by archipelago also revealed differences in incidence rates with the most remote archipelagos having the highest incidence. These high rates observed highlight the need to develop prevention tools in order to reduce the incidence. Results from our model of changes in the incidence of ciguatera disease following algae blooms might be useful for assisting ciguatera risk management initiatives. Indeed, results from the study highlight a clear temporal relation between ciguatera disease and its etiologic agent: Gambierdiscus spp. From a clinical point of view, our results confirm the neurological feature of this intoxication as previously proposed and suggest that several symptoms observed in 183 patients at the acute phase of the disease are still persistent 2 months after the onset. In order to characterize these symptoms, we compared the neurological evaluation of 47 patients with ciguatera disease to 125 ciguatera-free controls. Results showed that ciguatera disease predominantly alters the peripheral sensory system represented mainly by sensory disturbances (light-touch and thermal) and poorer sway performances compared to controls. Over three testing periods, we observed an improvement of sway performances but, light touch threshold remained altered for more than 50% of patient 60 days after of the onset. In summary, results obtained in this thesis confirm the evolution ciguatera disease to chronic stage in the study population and suggest that ciguatera symptoms in acute phase are similar to a sensory polyneuropathy with a progressive recovery.
Document Type: Thèse de doctorat
Issue Date: 2005
Open Access Date: 11 April 2018
Permalink: http://hdl.handle.net/20.500.11794/18022
Grantor: Université Laval
Collection:Thèses et mémoires

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