Arsenic poisoning
Diagnosis
History; clinical and post-mortem findings including gastritis or enteritis; detection of a significant concentration of arsenic in the ingesta or tissues of the dead animal. In chronically exposed animals, detection of arsenic in the milk or uring.
Specimens required
Each specimen should be packed in a separate container, clearly labelled and submitted chilled.
- 250 g ruminal or stomach contents submitted chilled for toxicology (Reinsch test).
- 50 g of liver from the dead animal, submitted chilled for toxicology.
NB.
Arsenic analysis of tissue is not routinely undertaken, due to the costs. In most cases, a positive Reinsch test (indicates > 1mg arsenic /kg) on rumen contents from animals with a suggestive history and lesions is adequate qualitative confirmation.
- 50 ml of milk or urine for arsenic analysis (only where chronic exposure is suspected).
- 50 g of suspect source material for toxicology, to be examined only if arsenic poisoning has been confirmed in the animal.
- Specimens required to allow for a differential diagnosis if arsenic is not the cause.
Interpretation of tissue and secreta arsenic concentrations
| Sample | Units | Normal | Possibly toxic | Toxic |
|---|---|---|---|---|
| Liver, kidney | mg/kg(wet wt) | <0.5 | 0.5-8 | >8 |
| Milk | mg/kg(wet wt) | <0.25 | 0.25-1.5 | >1.5 |
| Urine | mg/kg(wet wt) | <0.25 | 2-100 |
Interpretation depends on the interval between exposure and sampling. Maximum concentrations of arsenic in tissues occur about eight hours after ingestion, and animals that survive for 2 to 3 days may have liver concentrations as low as 2 mg/kg. Conversely clinically normal stock, chronically exposed to arsenic (eg via arsenic contaminated feed over a long period or, in the past stock regularly treated in arsenical dips) may have liver concentrations up to 8 mg/kg and milk concentrations to 1.5 mg/kg.