Fenbendazole and Albendazole Toxicity in Pigeons and Doves

Abstract Medical records and necropsy reports of 410 pigeons and doves from the Zoological Society of San Diego were examined to determine if birds treated with fenbendazole (FBZ) or albendazole (ABZ) had a higher incidence of toxic-related signs than untreated control birds. Birds presented for nonmedical reasons (quarantine, relocation, preshipment examinations, and routine parasite screening) were used exclusively to avoid confounding variables. Birds were observed for 45 days after presentation. Compared with a 4–6% mean weight gain in control birds during the treatment period or hospitalization, birds treated with FBZ had a mean weight loss of 16.1% (P < .001), and birds treated with ABZ had a mean weight loss of 13.3% (P = .004). The percentage of birds with marked leukopenia (white blood cell < 1000/μ l) was higher in FBZ-treated birds (87.5%, P < .001) and ABZ-treated birds (100%, P = .013) than in control birds (12.5%). Bone marrow hypoplasia was found in FBZ-treated birds (48.6%, P < .001) and A...