Diarrheic shellfish poisoning due to toxic mussel consumption: The first recorded outbreak in Greece

Abstract

During the week of 14–20 January 2000, 120 people visited the Emergency Departments of hospitals in Thessaloniki, northern Greece, complaining of acute gastrointestinal illness after eating mussels (Mytilus galloprovincialis). The symptoms indicated diarrhoeic shellfish poisoning, and the toxicity of mussels harvested from Thermaikos Gulf in Thessaloniki during the outbreak was investigated using mouse bioassays. The bioassays revealed toxicity to mice by the mussel samples; while high numbers of toxic algae Dinophysis acuminata were identified in water samples from Thermaikos Gulf. The harvesting of mussels was immediately suspended and a monitoring programme for algal blooms was established from then onwards. During a follow-up of the mussels’ toxicity from January 2000 to January 2005, two more mussel samples were found positive for diarrheic shellfish poisoning: one harvested in March 2001 from the area of the outbreak (Thermaikos Gulf) and the other harvested in January 2001 from Amvrakikos Gulf in north-western Greece. However, no sporadic cases or outbreaks were reported during this period.

Keywords:

• Diarrheic shellfish poisoning
• Greece
• mussels
• algal toxins
• Dinophysis
• outbreak

Acknowledgements

The study was carried out during a bilateral joint research project on Marine Biotoxins, in participation with the Biotoxins Unit, Food Safety Microbiology Laboratory, CPHLS, London, UK; and the Food Microbiology Unit, Microbiology Department, Medical School, University of Ioannina, Greece. The joint project was financially supported by grants from the General Secretariat for Research and Technology, The Greek Ministry of Development, and The British Council. The authors also wish to thank the former Director of the Clinical Microbiology Laboratory, Hospital for Infectious Diseases, Dr V. Daneilides, for collecting and sending the two mussel samples during the outbreak. Mouse bioassays complied with the current laws of Greece for laboratory animal experimentation.