Chronic plumbism in rabbits: a comparison of three diagnostic tests

Three groups of rabbits (A, B, and C; 6 rabbits/group) were fed a lead supplement of 25, 50, and 100 mg of Pb/kg of live weight/day for 87 days to compare the efficacies of 3 diagnostic tests--whole blood lead concentration, urinary delta-aminolevulinic acid (UALA), and fluorescent erythrocyte test (FET)--and to determine the clinicopathologic changes of experimentally induced lead poisoning in rabbits. All rabbits given lead had whole-blood lead concentrations greater then the maximum value (0.030 mg/dl) for control rabbits (group D), indicating that this measurement is a reliable indicator of lead ingestion. All group A rabbits (fed 25 mg of Pb/kg) and 66% negative UALA test results, with values less than the maximum value (0.12 mg/dl) for group D (control) rabbits. Only group C rabbits (fed 100 mg of Pb/kg) had consistently positive UALA FINDINGS. The test was therefore considered unreliable for detecting daily lead intakes less than 100 mg/kg of live weight of rabbits. All rabbits given lead had erythrocytes which fluoresced red when exposed to light rays with wavelenghts from 320 to 400 nm; fluorescence was not observed in erythrocytes of control rabbits. The FET appears to be a convenient and reliable diagnostic test for lead ingestion. In groups B and C, clinical signs of lead poisoning were mild, nonpersistent anemia characterized by the presence of poikilocytes, hupochromic erythrocytes, target cells, erythroblasts, erythrocytes with punctate basophilic stippling, reduced mean corpuscular hemoglobin concentrations, and relative lymphocytosis, neutropenia, and eosinopenia. One rabbit from the group fed the largest dose displayed partial anorexia.