With the summer in full swing and molluscs invading the vegetable patch, the opportunity for accidental ingestion of slug/snail bait products is increased.
In New Zealand there are two main compounds used in slug/snail bait products: metaldehyde and iron EDTA. While most of us are familiar with metaldehyde toxicity, cases of toxicity due to ingestion of iron EDTA are also seen periodically through our laboratory.
The following is a summary of the clinical signs and methods of diagnosis for these two compounds.
Clinical signs: These are predominantly neurotoxic. With cases of mild toxicity, signs include frothing at the mouth, anxiety/hyperesthesia, twitching, vomiting, diarrhoea, abdominal pain. This progresses to tremors, ataxia, seizuring, CNS depression, coma and death in severe cases of poisoning.
Diagnosis: Clinical signs combined with history of access are often sufficient for diagnosis. Characteristic green discoloration or visualisation of green particulate material in the vomitus or GI contents is helpful supporting evidence. Testing of stomach contents for metaldehyde is also available.
Clinical signs: Signs of toxicity are generally seen 6 – 12 hours after ingestion. The clinical signs tend to be GI-associated and include acute abdominal pain, diarrhoea, which may often be haemorrhagic, and vomiting.1
Diagnosis: Measurement of serum iron. Serum iron may also be used to monitor success of chelation therapy. Chelation therapy is recommended to treat iron EDTA toxicity as the body has a very limited ability to excrete excess iron. After commencement of chelation therapy the urine turns a red-rust colour and the disappearance of this discoloration may also be used to monitor success of treatment.
1. Haldane SL, Davis RM. Acute toxicity in five dogs after ingestion of a commercial small and slug bait containing iron EDTA. Aus. Vet. J. 2009;87:284-286.