Food-Borne Disease Outbreak of Diarrhetic Shellfish Poisoning Due to Toxic Mussel Consumption: The First Recorded Outbreak in China

Abstract

ObjectivesThis investigation was undertaken in response to an outbreak of suspected shellfish poisoning in Zhejiang Province, China. The objectives of this project were to confirm the outbreak and to identify the aetiology, source and mode of transmission.MethodsA probable case was defined as an individual with diarrhea (≥3 times/day) plus at least one of the following symptoms: fever (≥37.5°C), vomiting, or abdominal pain after consuming seafood between May 23rd and May 28th, 2011. Using a case-control study design, we compared exposures to suspected seafood items and cooking methods between 61 probable cases and 61 controls.ResultsOver 220 suspected or probable cases of diarrhetic shellfish poisoning (DSP) were identified (incidence of 18 cases per 100,000). The case control study revealed that 100% of cases and 18% of controls had eaten mussels during the exposure period (OR = ∞, χ2 = 84.72,P = 0.000). The number of mussels consumed was related to DSP risk (P = 0.004, χ2 test for trend). Consumption of other seafood items was not associated with disease. The frequency of diarrhea and vomiting were positively correlated with the number of mussels consumed (r = 0.424 and r = 0.562, respectively). The frequency of vomiting and the incubation period were significantly correlated with the total time the mussels were boiled (r = 0.594 and r = −0.336, respectively). Mussels from 3 food markets and one family contained Okadaic acid (OA) and Dinophysistoxin-1 (DTX-1).ConclusionsThis outbreak was attributed to the consumption of mussels contaminated by DSP-toxins (OA and DTX-1) which are produced by different species of dinoflagellates (toxic microalgae) from the genus Dinophysis or Prorocentrum. Suspension of mussel sales and early public announcements were highly effective in controlling the outbreak, although oversight of seafood quality should be a priority to prevent future contamination and outbreaks.

Distribution of Marine Lipophilic Toxins in Shellfish Products Collected from the Chinese Market

“…In China, OA is recognized as the main cause of diarrheic shellfish poisoning (DSP) [ 3 , 4 , 8 , 13 ]. Among the five toxins tested in this study, OA was the only one found in all locations, with the highest prevalence (37.8%) occurring in QD.…”

“…In addition, traditional Chinese methods of processing shellfish, such as cooking, steaming, and autoclaving, increase the concentration of lipophilic marine biotoxins (okadaic acid (OA)-, azaspiracid (AZA)-, pectenotoxin (PTX)-, and yessotoxin (YTX)-group toxins) approximately two-fold due to water loss [ 2 ]. Occasional but serious poisoning events, which led to more than 200 people suffering illness, occurred in the cities of Ningbo and Ningde near the East China Sea in 2011 [ 3 , 4 ].…”

Food Safety in Low and Middle Income Countries

“…Paralytic shellfish poisoning caused by the algae producing the toxin "red tides” is most common in colder waters. Diarrhetic shellfish poisoning is common in Europe but found worldwide and was recently reported in China [ 59 ]. Scombrotoxic fish poisoning is a syndrome resembling an allergic reaction caused by eating fish with high levels of histamine produced by bacterial spoilage.…”

Selection and application of aptamers with high-affinity and high-specificity against dinophysistoxin-1

“…2,3 However, recent studies indicate that DSP is emerging in more regions in the world. [4][5][6] The emergence of DSP also leads to the downturn of the shellsh industry, and the length of time is unexpected. 7 Not only does it have a serious economic impact, but it also poses a great threat to human health.…”