Unintentional ingestion of Cordyceps fungus-infected cicada nymphs causing ibotenic acid poisoning in Southern Vietnam

Abstract

Background: Cordyceps fungus found in infected cicada nymphs (“cicada flowers”) is utilized in traditional Chinese medicine. Cordyceps fungus toxicity in humans has not been previously reported. We report 60 cases of apparent Cordyceps poisoning in Southern Vietnam.

Methods: We retrospectively collected demographic and clinical data from the medical records (21 cases) and by telephone interview (39 cases) of patients admitted to seven hospitals in Southern Vietnam following ingestion of cicada flowers between 2008 and 2015. We also determined the species of Cordyceps present in the cicada flowers and performed a partial chemical analysis of the fungus.

Results: Sixty cases of toxic effects following ingestion of cicada flowers were documented. Symptom onset occurred within 60 minutes following ingestion. Symptoms included dizziness, vomiting, salivation, mydriasis, jaw stiffness, urinary retention, seizures, agitated delirium, hallucinations, somnolence and coma. None of the patients suffered liver or kidney injury. There was one fatality. The Cordyceps fungus involved in these poisoning was identified as Ophiocordyceps heteropoda. The presence of ibotenic acid was confirmed, but musimol and muscarine were absent.

Conclusions: Cicada infected with Ophiocordyceps heteropoda in Vietnam contain ibotenic acid and are associated with a clinical syndrome consistent with its effects.

Keywords:

• Cordyceps fungus poisoning
• Ophiocordyceps heteropoda
• cicada flower
• Vietnam
• cicada nymphs
• ibotenic acid

Acknowledgments

Uyen Vy is grateful to Professor, Dr. Viet Van Truong, the former President of Cho Ray Hospital, Vietnam, for supporting the collection of samples of the Cordyceps fungus in An Giang Province of Vietnam. She is also thankful to her colleagues at the Cho Ray Hospital, the Pharmacy faculty, University of Medicine and Pharmacy at Ho Chi Minh city Ho Chi Minh City and the Institute of Public Health of Ho Chi Minh City, who helped with the collection of data and the toxin analysis. Furthermore, she express thanks to colleagues at Children’s Hospital Number One, who facilitated the identification of the Cordyceps spp by sending the sample to the University of Natural Science of Ho Chi Minh City.

Disclosure statement

No potential conflict of interest was reported by the authors.