First report of (homo)anatoxin-a and dog neurotoxicosis after ingestion of benthic cyanobacteria in The Netherlands

► In The Netherlands, three dogs died after swimming. ► Clinical symptoms and necropsy pointed towards neurotoxicosis. ► Cyanobacteria and the neurotoxins (homo)anatoxin-a were found in stomach contents. ► Ingestion of the cyanobacterium Phormidium has caused the dogs' death. ► First report of (homo)anatoxin-a occurrence and poisoning in The Netherlands.