Paralytic Shellfish Poisoning Outbreak-Oregon, United States, 2024

Area of Science:

• Public Health
• Environmental Health
• Toxicology

Background:

• A significant paralytic shellfish poisoning (PSP) outbreak occurred on the Oregon Coast in May-June 2024.
• The outbreak was linked to the consumption of self-harvested shellfish contaminated with marine toxins.

Purpose of the Study:

• To investigate the clinical characteristics and exposures associated with the 2024 Oregon PSP outbreak.
• To identify the scope of the outbreak and implement measures to prevent further illnesses.
• To evaluate the challenges in detecting and responding to rapidly increasing marine toxin levels.

Main Methods:

• Case identification through reports from the Oregon Poison Center and Oregon Health Authority.
• Epidemiological investigation including clinical assessment and exposure history.
• Analysis of paralytic shellfish toxin (PST) levels in shellfish tissue samples.

Main Results:

• Forty-two cases of PSP were identified, with symptom onset within 5 hours of shellfish consumption.
• Illnesses resulted in 7 hospitalizations; no deaths were reported.
• Shellfish samples, particularly mussels, showed PST levels significantly exceeding the closure threshold, with one sample at a record high for Oregon.

Conclusions:

• The 2024 Oregon PSP outbreak was the largest on record, characterized by a rapid increase in PST levels.
• Timely detection and closure of harvest areas were challenged by the swift rise in toxin concentrations.
• Enhanced rapid detection methods for PST and continued collaboration among health agencies are crucial for future outbreak prevention and response.