Dinophysis and Diarrhetic Shellfish Poisoning: Developments and Collaborations for Early Detection and Public Safety in the Salish Sea

Diarrhetic shellfish poisoning (DSP) is an emerging health threat to the people who consume shellfish from the Salish Sea. The toxins responsible for causing DSP in humans are collectively called the diarrhetic shellfish toxins (DSTs) and include okadaic acid and dinophysistoxins. DSTs are produced by dinoflagellates in the genus Dinophysis – heterotrophs that can feed through myzocytosis or “cellular vampirism”. Although Dinophysis have been observed in the Salish Sea for many years, the first confirmed case of DSP occurred in 2011 after a family consumed mussels harvested from Sequim Bay. Dinophysis typically are observed in low cell densities (10-40 cells L-1) and DSP events documented in Europe and North America have been associated with cell densities as low as 100-200 cells L-1. A critical component of a monitoring program for DSP is rapid and early detection and enumeration of Dinophysis cells in seawater at these low densities. Developing and applying molecular tools and automated technologies will allow for near real-time detection and enumeration of Dinophysis cells. A quantitative PCR assay, currently being developed for laboratory bench top use, will be adapted for use in the field with the Environmental Sample Processor (ESP). The ESP is a robotic, autonomous sampler that can analyze samples immediately after collection or store them for later analysis. The ESP can be placed strategically in areas known to have experienced high concentrations of Dinophysis and DSTs, for focal monitoring with high temporal resolution. The bench top quantitative PCR assay can also be used by complementary programs, such as SoundToxins and the Olympic Region Harmful Algal Bloom partnership in Washington State and the Harmful Algae Monitoring Program in British Columbia to provide early warning of Dinophysis at multiple sites where partners can collect follow up seawater and shellfish samples for confirmation of toxicity at State and Federal laboratories.