A National Ocean Service/National Center for Coastal Ocean Science Program
Phytoplankton Monitoring Network
Promoting a better understanding of harmful algal blooms by way of volunteer monitoring
Resources
Karenia brevis
Species Distribution:
Karenia brevis, is a toxic dinoflagellate found in the Gulf of Mexico along the Texas and Louisiana coasts, the east
coast of Florida, and as far north as North Carolina. K. brevis red tides are typically characterized by patches of discolored water, dead or dying fish, and
toxic aerosols resulting in respiratory irritation in humans. Similar nontoxic species have been found worldwide.
Toxins/Mode of Action: Brevetoxins (PbTx) and related derivatives
Brevetoxins are lipid soluble polyethers that lower the activation threshold of voltage dependent sodium channels and enhance depolarization of nerve cells,
leading to uncontrolled Na+ influx into the cell. full chemical structure
Human Health Syndrome: Neurotoxic Shellfish Poisoning (NSP)
Neurotoxic shellfish poisoning (NSP) produces gastrointestinal and neurological symptoms within 3 to 6 hours of ingestion of contaminated shellfish. Milder cases
may include symptoms of headaches, diarrhea, and muscle/ joint pain. More severe effects are altered perceptions of hot and cold, difficulty breathing, or
double vision. Milder toxicity commonly occurs on beaches where people are exposed to toxin aerosols produced by wave action. Symptoms include irritation
of the throat and upper respiratory tract causing asthma-like effects. Learn more about neurotoxic shellfish toxins in an excerpt from Diversity of Marine and Freshwater Algal Toxins
