Azaspiracids are a group of toxins first reported in the 1990s in Western European waters and are now reported to occur along both the East and West coasts of North America. While the organism producing these toxins has been identified, the mechanism by which azaspiracids exert their toxic effects remains to be determined. We are conducting studies to better understand the toxicology of azaspiracids, an emerging class of algal toxins in United States coastal waters.

Why We Care
Azaspiracids are a group of algal toxins responsible for the human illness known as azaspiracid shellfish poisoning (AZP), first encountered in Western Europe in the mid-1990s. Since then, multiple AZP outbreaks involving human illness have been reported in several European countries. The toxin has been detected in shellfish from North Africa and eastern Canada, and most recently in the Pacific Northwest area of the United States. With clear evidence that azaspiracids are present in shellfish from United States waters, including oysters, mussels, and razor clams, establishing the mechanism of toxicity for these compounds is critical and essential to understanding the human health risks presented by these emerging toxins.

What We Are Doing
In collaboration with our partners, we began by obtaining sufficient purified azaspiracids to conduct toxicology tests in the laboratory. We are working with scientists from the University of Michigan at Dearborn, the National Research Council of Canada, the Irish Marine Institute, and others in the European Union.

What We Are Finding
Toxic effects of azaspiracids on human cells:

• toxic to many different cell lines;
• cause morphological changes to cells;
• alter gene expression patterns in cells;
• cause decline in cell cholesterol levels.

Toxic effects of azaspiracids on fish:

• disrupt the development of embryos.

In addition, there appear to be clear differences in the toxicity of different azaspiracids and possibly the way they exert their toxic effects, all of which will be need to be taken into account when monitoring these toxins in shellfish and assessing the risk they pose to consumers.

Next Steps
We continue to perform laboratory studies to try and identify the precise mode of action for the azaspiracids. In addition, we are working with our partners to perform studies using mammalian model systems to better understand and ultimately predict how these toxins may be metabolized or processed following ingestion of contaminated shellfish by humans.