Animals as Sentinels for Human Lead Exposure: A Case Report

Because human and nonhuman animals often share the same environment, there is potential concurrent exposure to toxicants. As a result, domestic animals can be used as sentinels for exposure of people to these agents. Here we present a case illustrating exposure of both humans and domestic animals to lead contamination in their environments. This case study occurred at a farm where cattle deaths were determined to have been caused by lead poisoning based on elevated postmortem tissue lead concentrations. Elevated blood lead concentrations were detected in the remaining cattle, a dog, a cat, and a pregnant woman (37.3 mu g/dL) living on the farm. The range of blood lead concentrations in the domestic animals was 8.42 (cat) to 85.41 mu g/dL (calf), although clinical signs of lead poisoning were not apparent in these animals. Further testing revealed the most likely source for lead exposure to be paint in the barn and home. Household dogs and cats have been used as sentinels for lead poisoning in humans, but cattle may also act as a sentinel species for environmental lead contamination.