Downloaded from http://veterinaryrecord.bmj.com/ on June 20, 2015 - Published by group.bmj.com
Gazette
Letters TOXICOLOGY
Fatal poisoning of a dog by the fungus Clitocybe rivulosa IN October 2006, one of the authors (A. G. Irwin) was contacted by a woman whose nine-year-old cocker spaniel had died after apparently consuming fungus fruiting bodies from the garden lawn. The owner had collected a sample of the dog’s vomit, which clearly showed fragments of undigested fungus. Fungi collected from the lawn included fool’s funnel (Clitocybe rivulosa), a species known to cause poisoning in humans. Examination of the ingested fragments under the microscope revealed distinctive spores that matched those of C rivulosa. The time between ingestion and the onset of clinical signs is not known but within 45 minutes of the dog displaying salivation, vomiting and diarrhoea it had collapsed and died. It is reported that the dog was otherwise in good health and had never required veterinary treatment. These signs are consistent with poisoning by 122 | Veterinary Record | August 2, 2014
muscarine, a toxin known to be present in a number of small whitish Clitocybe species. By binding to cholinergic receptors in the parasympathetic nervous system, muscarine stimulates smooth muscle contraction and the flow of tears, sweat, saliva and other secretions. Atropine is a recognised antidote for muscarine poisoning but no treatment was given in this case. The lethal dose for muscarine in humans is reported to lie in the range 180 mg to 300 mg (Puschner 2007) but it is difficult to find authenticated instances of human death due to ingestion of British species of Clitocybe. However, muscarine is also found in significant concentrations in some fungi of the genus Inocybe, mostly small brownish toadstools, and human deaths have been attributed to ingestion of Inocybe erubescens (formerly known as Inocybe patouillardii), the deadly or red-staining fibrecap. Poisoning due to ingestion of the collared fibrecap (Inocybe cincinnata, formerly known as Inocybe phaeocomis), has been recorded in a springer spaniel by Yam and others (1994). The dog had episodes of vomiting and diarrhoea but recovered. In Argentina, Soto and others (2000) recorded the death of a German shepherd dog from cardiac and respiratory arrest after feeding
where the fungus Chlorophyllum molybdites was present. Three others showed signs of poisoning by a cholinergic agent. However, in humans, poisoning by this fungus is only occasional and does not usually elicit the symptoms of parasympathetic stimulation. Dogs have also been fatally poisoned by Amanita phalloides (death cap) (Cole 1993) and Amanita pantherina (panther cap) (Hunt and Funk 1977), neither of which produce muscarinic clinical signs. Why a dog should eat a fungus is not clear but some species of Clitocybe (although not C rivulosa) smell strongly of aniseed; C rivulosa itself smells slightly mealy or sweet to the human nose. Whether dogs are more or less sensitive than humans to muscarine is not known but variation between species could largely be due to differences in absorption from the gastrointestinal tract. In the rabbit, muscarine is hardly absorbed at all but this species, as well as cats and mice, is very sensitive to it if administered intravenously or parenterally (Benjamin 1995). C rivulosa is the most common of the small whitish Clitocybe species found in Britain and the only one occurring in significant numbers on lawns. Until recently it was separated from the very
Downloaded from http://veterinaryrecord.bmj.com/ on June 20, 2015 - Published by group.bmj.com
Letters similar Clitocybe dealbata (ivory funnel) but the two have now been synonymised (Legon and Henrici 2005). The caps are whitish, flat to undulating, becoming slightly depressed at the centre, and are 2 cm to 5 cm in diameter. The surface is often hoary and slightly flesh-coloured but can be white and glossy; concentric zones are sometimes visible on the cap and the surface can be cracked. The rest of the fungus is similarly coloured, including the gills which are crowded together. This species typically occurs in scattered clusters and can occasionally form rings of fruiting bodies on lawns. We are grateful to Trevor Dove for providing additional information and Ian Keymer for helpful comments. A. G. Irwin, Norwich Castle Museum and Art Gallery, Castle Meadow, Norwich NR1 3JU A. R. Leech, 3 Eccles Road, Holt, Norfolk NR25 6HJ e-mail: [email protected]
References
BENJAMIN, D. R. (1995) Mushrooms: Poisons and Panaceas. W. H. Freeman & Company COLE, F. M. (1993) A puppy death and Amanita phalloides. Australian Veterinary Journal 70, 271-272 HUNT, R. S. & FUNK, A. (1977) A mushroom fatal to dogs. Mycologia 69, 432-433 LEGON, N. W. & HENRICI, A. (2005) Checklist of the British and Irish Basidiomycota. Royal Botanic Gardens, Kew PUSCHNER, B. (2007) Mushroom toxins. In Veterinary Toxicology: Basic and Clinical Principles. Ed R. C. Gupta. Academic Press. pp 915-925 SOTO, M. K., CARMARAN, C. C. & BRUZZI, H. (2000) Suspected poisonings of domestic dogs by Macrolepiota molybdites. Mycologist 14, 50-51 YAM, P., HELFER, S. & WATLING, R. (1994) Poisoning of a domestic dog by Inocybe phaeocomis (pers.) kuyper. Mycologist 8, 50-51
doi: 10.1136/vr.g4879
August 2, 2014 | Veterinary Record | 123
Downloaded from http://veterinaryrecord.bmj.com/ on June 20, 2015 - Published by group.bmj.com
Fatal poisoning of a dog by the fungus Clitocybe rivulosa A. G. Irwin and A. R. Leech Veterinary Record 2014 175: 122-123
doi: 10.1136/vr.g4879 Updated information and services can be found at: http://veterinaryrecord.bmj.com/content/175/5/122.1
These include:
References Email alerting service
This article cites 4 articles, 0 of which you can access for free at: http://veterinaryrecord.bmj.com/content/175/5/122.1#BIBL Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article.
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform To subscribe to BMJ go to: http://group.bmj.com/subscribe/
Gazette
Letters TOXICOLOGY
Fatal poisoning of a dog by the fungus Clitocybe rivulosa IN October 2006, one of the authors (A. G. Irwin) was contacted by a woman whose nine-year-old cocker spaniel had died after apparently consuming fungus fruiting bodies from the garden lawn. The owner had collected a sample of the dog’s vomit, which clearly showed fragments of undigested fungus. Fungi collected from the lawn included fool’s funnel (Clitocybe rivulosa), a species known to cause poisoning in humans. Examination of the ingested fragments under the microscope revealed distinctive spores that matched those of C rivulosa. The time between ingestion and the onset of clinical signs is not known but within 45 minutes of the dog displaying salivation, vomiting and diarrhoea it had collapsed and died. It is reported that the dog was otherwise in good health and had never required veterinary treatment. These signs are consistent with poisoning by 122 | Veterinary Record | August 2, 2014
muscarine, a toxin known to be present in a number of small whitish Clitocybe species. By binding to cholinergic receptors in the parasympathetic nervous system, muscarine stimulates smooth muscle contraction and the flow of tears, sweat, saliva and other secretions. Atropine is a recognised antidote for muscarine poisoning but no treatment was given in this case. The lethal dose for muscarine in humans is reported to lie in the range 180 mg to 300 mg (Puschner 2007) but it is difficult to find authenticated instances of human death due to ingestion of British species of Clitocybe. However, muscarine is also found in significant concentrations in some fungi of the genus Inocybe, mostly small brownish toadstools, and human deaths have been attributed to ingestion of Inocybe erubescens (formerly known as Inocybe patouillardii), the deadly or red-staining fibrecap. Poisoning due to ingestion of the collared fibrecap (Inocybe cincinnata, formerly known as Inocybe phaeocomis), has been recorded in a springer spaniel by Yam and others (1994). The dog had episodes of vomiting and diarrhoea but recovered. In Argentina, Soto and others (2000) recorded the death of a German shepherd dog from cardiac and respiratory arrest after feeding
where the fungus Chlorophyllum molybdites was present. Three others showed signs of poisoning by a cholinergic agent. However, in humans, poisoning by this fungus is only occasional and does not usually elicit the symptoms of parasympathetic stimulation. Dogs have also been fatally poisoned by Amanita phalloides (death cap) (Cole 1993) and Amanita pantherina (panther cap) (Hunt and Funk 1977), neither of which produce muscarinic clinical signs. Why a dog should eat a fungus is not clear but some species of Clitocybe (although not C rivulosa) smell strongly of aniseed; C rivulosa itself smells slightly mealy or sweet to the human nose. Whether dogs are more or less sensitive than humans to muscarine is not known but variation between species could largely be due to differences in absorption from the gastrointestinal tract. In the rabbit, muscarine is hardly absorbed at all but this species, as well as cats and mice, is very sensitive to it if administered intravenously or parenterally (Benjamin 1995). C rivulosa is the most common of the small whitish Clitocybe species found in Britain and the only one occurring in significant numbers on lawns. Until recently it was separated from the very
Downloaded from http://veterinaryrecord.bmj.com/ on June 20, 2015 - Published by group.bmj.com
Letters similar Clitocybe dealbata (ivory funnel) but the two have now been synonymised (Legon and Henrici 2005). The caps are whitish, flat to undulating, becoming slightly depressed at the centre, and are 2 cm to 5 cm in diameter. The surface is often hoary and slightly flesh-coloured but can be white and glossy; concentric zones are sometimes visible on the cap and the surface can be cracked. The rest of the fungus is similarly coloured, including the gills which are crowded together. This species typically occurs in scattered clusters and can occasionally form rings of fruiting bodies on lawns. We are grateful to Trevor Dove for providing additional information and Ian Keymer for helpful comments. A. G. Irwin, Norwich Castle Museum and Art Gallery, Castle Meadow, Norwich NR1 3JU A. R. Leech, 3 Eccles Road, Holt, Norfolk NR25 6HJ e-mail: [email protected]
References
BENJAMIN, D. R. (1995) Mushrooms: Poisons and Panaceas. W. H. Freeman & Company COLE, F. M. (1993) A puppy death and Amanita phalloides. Australian Veterinary Journal 70, 271-272 HUNT, R. S. & FUNK, A. (1977) A mushroom fatal to dogs. Mycologia 69, 432-433 LEGON, N. W. & HENRICI, A. (2005) Checklist of the British and Irish Basidiomycota. Royal Botanic Gardens, Kew PUSCHNER, B. (2007) Mushroom toxins. In Veterinary Toxicology: Basic and Clinical Principles. Ed R. C. Gupta. Academic Press. pp 915-925 SOTO, M. K., CARMARAN, C. C. & BRUZZI, H. (2000) Suspected poisonings of domestic dogs by Macrolepiota molybdites. Mycologist 14, 50-51 YAM, P., HELFER, S. & WATLING, R. (1994) Poisoning of a domestic dog by Inocybe phaeocomis (pers.) kuyper. Mycologist 8, 50-51
doi: 10.1136/vr.g4879
August 2, 2014 | Veterinary Record | 123
Downloaded from http://veterinaryrecord.bmj.com/ on June 20, 2015 - Published by group.bmj.com
Fatal poisoning of a dog by the fungus Clitocybe rivulosa A. G. Irwin and A. R. Leech Veterinary Record 2014 175: 122-123
doi: 10.1136/vr.g4879 Updated information and services can be found at: http://veterinaryrecord.bmj.com/content/175/5/122.1
These include:
References Email alerting service
This article cites 4 articles, 0 of which you can access for free at: http://veterinaryrecord.bmj.com/content/175/5/122.1#BIBL Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article.
Notes
To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform To subscribe to BMJ go to: http://group.bmj.com/subscribe/
