Acid-fast inclusions in osteoclasts of a lead poisoned dog

Experimental lead toxicosis of raccoons (Procyon lotor)

Four pairs of raccoons were treated orally with the following doses of lead acetate (mg/kg; 5 days/week, for 8 weeks): 0 (control), 1, 2 and 4. In the six experimental animals, this treatment produced dose-dependent increases in blood lead, without clinical signs or changes in haematological parameters. After 8 weeks, the liver and kidney of all lead-treated animals and the calvarium and radius of those receiving doses of 2 and 4 mg/kg contained elevated concentrations of lead. Acid-fast inclusions were observed by light and electron microscopy in the kidneys of all raccoons receiving the two highest doses and in one animal receiving the lowest dose. Hepatic acid-fast inclusions were seen in only one animal (dose 4 mg/kg). No inclusions were seen in osteoclasts of the radius. It is suggested that the findings, which support earlier observations that raccoons are fairly resistant to lead, may be of value in studying interactions between lead exposure and oral vaccination of wildlife against rabies.

An outbreak of lead poisoning in dogs

An outbreak of lead toxicosis in working dogs on a sheep farm is described. The affected dogs exhibited neurological signs which appeared to be initiated by strenuous physical activity. Radiological examination and estimation of urinary delta aminolevulinic acid (U-ALA) was not found to be useful for clinical diagnosis but blood lead estimation was helpful in detecting and confirming dogs that were exposed to lead. Gross pathological lesions were absent in a lead poisoned dog. However, histopathological lesions were seen in brain and bone. Acid-fast lead inclusion were not detected in liver and kidney epithelial cells but were present in osteoclasts.