To the Editor:
We read with interest the study of lipid emulsion in acute glyphosate toxicity by Gil et al. (2013).Citation1 These authors state that glyphosate intoxication has been considered minimally toxic to animals. Although this may be true for glyphosate itself in experimental animals, in our experience accidental exposure to glyphosate products is a concern in dogs and, more particularly, cats.
Since 1991 the Veterinary Poisons Information Service (VPIS) in the UK has received 1,323 enquiries about cats (n = 331) and dogs (n = 992) exposed to glyphosate products. Of these, 63 cases in cats and 229 cases in dogs involving only glyphosate products have follow-up data obtained by postal questionnaire. Out of these, 13 (21%) cats and 77 (34%) dogs were asymptomatic. Vomiting, diarrhoea and lethargy were by far the most common signs in dogs (65, 47 and 30 cases, respectively). Vomiting, anorexia and lethargy were the most common signs in cats (14, 11 and 10 cases respectively). Only four (8%) cats developed diarrhoea compared to 47 (31%) dogs. There were no reports of hypotension. Both cats and dogs developed respiratory signs. There were three cases of respiratory distress in cats and two in dogs. Pulmonary oedema was reported in five cats and five dogs. Severe respiratory complications were a particular feature of toxicity in cats with three cases of cyanosis and four of bronchopneumonia. Of the cats with cyanosis one died and two recovered. All the cats with bronchopneumonia had a fatal outcome (three died and one was euthanized). There were no cases of cyanosis or pneumonia in canine cases. Nine cats and nine dogs died in this series; five cats and two dogs were euthanized. Overall 22% of cats had a fatal outcome compared to 5% in dogs.
Glyphosate exposure has been reported previously in domestic animals.Citation2–4 The most common effects in the only study describing clinical signsCitation2 were depression and mucosal and gastrointestinal irritation, as described in the VPIS cases. There were no severe cases and all the dogs (n = 25) and cats (n = 4) recovered with supportive care.
Exposure to glyphosate products in companion animals is associated with gastrointestinal and respiratory effects and these signs are due to the surfactants used in these products. Cats are particularly at risk of severe respiratory complications. Intravenous lipid emulsion is used in veterinary medicine, but is unlikely to be required in glyphosate exposure in companion animals since hypotension and arrhythmias are uncommon in animal cases. In addition, the study by Gil et al. (2013) showed no effect of intravenous lipid administration on respiratory failure in humans.
Acknowledgements
The authors thank everyone who took the time to complete and return the VPIS follow up questionnaires.
References
- Gil HW, Park JS, Park SH, Hong SY. Effect of intravenous lipid emulsion in patients with acute glyphosate intoxication. Clin Toxicol (Phila) 2013; 51:767–771.
- Burgat V, Keck G, Guerre P, Bigorre V, Pineau X. Glyphosate toxicosis in domestic animals: a survey from the data of the centre National d’Informations Toxicologiques Veterinaires (CNITV). Vet Hum Toxicol 1998; 40:363–367.
- Giuliano Albo A, Nebbia C. Incidence of poisonings in domestic carnivores in Italy. Vet Res Comm 2004; 28:83–88.
- Berny P, Caloni F, Croubels S, Sachana M, Dandenbroucke V, Davanzo F, Guitart R. Animal poisoning in Europe. Part 2: Companion animals. Vet J 2010; 183:255–259.