Phylogenetic evidence revealed Cantharocybe virosa (Agaricales, Hygrophoraceae) as a new clinical record for gastrointestinal mushroom poisoning in Thailand.

Epidemiological data showed increasing incidence rates of gastrointestinal (GI) mushroom syndrome in Thailand. This study therefore, aimed to identify suspected GI toxin-containing mushrooms using DNA sequence analyses of the internal transcribed spacer (ITS) region and the large subunit (LSU) of nuclear ribosomal DNA. GI toxins were also identified using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). 39 patients presented with poisoning symptoms, including nausea, vomiting, fatigue, abdominal pain, circulatory disturbances and diarrhea after ingesting wild mushrooms. The latent periods varied from 30 min to 4 h, but mostly between 1 and 2 h. Results of the ITS sequence-based identification revealed high similarities for the obtained clinical mushroom samples with the genus Cantharocybe H.E. Bigelow & A.H. SM. Maximum likelihood and Bayesian summary trees of combined ITS and LSU data confirmed that these toxic mushroom samples ingested by the patients belonged to Cantharocybe virosa (Manim. & K.B. Vrinda) T.K.A. Kumar. Detection of GI toxins using LC-QTOF-MS method revealed the presence of coprine in C. virosa. This study described the first outbreak of C. virosa poisoning in Thailand which resulted in severe cases of gastrointestinal irritation. To prevent such poisoning cases it is essential to educate the public not to gather any unidentified or unfamiliar wild mushrooms. © Korean Society of Toxicology 2019.