Incidence of Ciguatoxin fish poisoning in Trivandrum, India

Abstract

Ciguatoxin (CTX) is a visibly unidentifiable, colourless, odourless, heat stable and lipid soluble polyether marine biotoxin associated with human illness. Marine dinoflagellates under the genus Gambierdiscus are responsible for producingciguatoxins (CTX). The ciguatoxin gets accumulated in herbivorous fishes, gets biotransformed in carnivorous fishes and finally reach fish consumers. In January 2016, individuals who consumed red snapper in Trivandrum, Kerala, India weresuspected to be intoxicated with ciguatera based on characteristic symptoms as assessed by medical team from Trivandrum Medical College, Kerala, India. The red snapper species was identified and confirmed as Lutjanus bohar by DNA barcoding. Mouse bioassay was carried out to detect the presence of ciguatoxin and the tested mice showed symptoms related to suspected CTX toxicity. Significantly higher level of ciguatoxin lethal dose was estimated which was found equivalent to 16.25 ng of CTX-1 which led to 13% of weight loss in tested mice. Medical professionals also investigated clinical manifestations of suspected toxicity in hospitalised individuals. This study indicated that there is a need for regular surveillance of seafood landed across the coast and consumer’s awareness for their safety.

Ciguatera poisonings: A global review of occurrences and trends

“…The first outbreak (June 2015) involved two individuals who became ill following consumption of a red snapper purchased from a local market (Rajeish et al, 2016), whereas the second outbreak (September 2016) affected > 200 people (Karunasagar et al, 2018). The confirmation of the presence of CTXs in implicated fish samples was further provided using a variety of toxicity methods including mouse bioassay, cytotoxicity and receptor binding assays, and LC-MS/MS (Rajisha et al, 2017a;Rajisha et al, 2017b;Karunasagar et al, 2018) (Table 3). A large-scale testing survey conducted on 262 locally caught reef fish further allowed confirmation of CTX-like activity in two specimens of L. bohar as assessed by MBA (Rajisha et al, 2017b) (Table 3).…”

Ciguatera in the Indian Ocean with Special Insights on the Arabian Sea and Adjacent Gulf and Seas: A Review

“…In Mangalore at the southwest coast of India, CP was first described during June 2015 outbreak involving red snapper( Lutjanus bohar ) [ 72 , 73 ], and a second outbreak during September 2016 involving red snapper again [ 74 ]. In another incidence, CP was also reported from Trivandrum, India [ 75 ].…”

“…The CP cases have mainly been reported in the southwestern region encompassing Comoros, Mayotte, La Reunion, Mauritius, Rodrigues, and Seychelles. The reports from the Northern part of the Indian ocean have been scarce and involve cases in Mangalore and Trivandrum on the southern Indian coast and an outbreak resulting in one fatality from Pakistan, but the fish species involved and their origin could not be confirmed [ 74 , 75 , 116 , 117 ]. Few cases of CFP were also reported in Thailand after eating ocean fish particularly sea bass and red snapper [ 118 , 119 ].…”

“…The fatality rate of this outbreak was 20% [ 121 ]. In Trivandrum, India, an autochthonous outbreak was reported in 2015 and 2016, due to which nearly 200 workers of a fish factory contracted CFP after eating heads of Red Snappers [ 75 ]. In 2013, also severe food poisoning events were witnessed after consuming a bull shark ( Carcharhinus leucas ), resulting in the deaths of 11 people in Madagascar in 2013 [ 78 ].…”

Evaluating Age and Growth Relationship to Ciguatoxicity in Five Coral Reef Fish Species from French Polynesia

“…Ciguatera poisoning (CP) is the most common seafood-borne poisoning worldwide [1]. Though originally endemic to tropical and intertropical regions, CP cases are now more commonly reported in semi-temperate areas in countries such as the Macaronesian Islands [2][3][4][5] or in the coast of continental countries such as India [6,7]. With an estimated 50,000 to 500,000 yearly cases worldwide, CP highest incidence rates (IRs) are consistently reported in endemic areas, i.e., the Caribbean Sea, and the Pacific and Indian Oceans [1,8,9].…”