Overview

• UC San Diego researchers sampled 84 fish across seven popular game species at five San Diego County locations and detected trematodes in the vast majority.
• They identified two invasive flatworms, Haplorchis pumilio in 93% of samples and Centrocestus formosanus in 91% at select sites.
• These parasites arrived from Southeast Asia via the red-rimmed melania snail and can cause gastrointestinal distress, weight loss, lethargy and, in rare cases, strokes or heart attacks.
• No human cases have been confirmed, but experts warn that lack of mandatory reporting and limited case detection could obscure actual infections.
• Proper cooking or freezing for at least one week neutralizes the worms, yet a social media survey found many consumers eating freshwater fish raw without precautions.