COMPARISON OF HEMATOLOGIC DIFFERENCES WITH LITHIUM HEPARIN AND DIPOTASSIUM ETHYLENEDIAMINETETRAACETIC ACID IN EUROPEAN STARLINGS (STURNUS VULGARIS).

Preservation of blood through use of anticoagulants allows delayed assessment of hematologic health and is commonly employed in veterinary health assessments. The two most common anticoagulants are lithium heparin (LH) and dipotassium ethylenediaminetetraacetic acid (EDTA), and their effects can vary widely between species. The hematologic effects of these anticoagulants on blood from European starlings (Sturnus vulgaris) have not been established, and these birds could serve as models for passerine species both in managed collections and in the wild. Blood was drawn from 45 European starlings and immediately divided into either LH or EDTA microtainers. For each sample, packed cell volume (PCV), total solids (TS), and complete blood counts were performed. There were no significant differences between EDTA and LH anticoagulated blood for PCV, white blood cell count (WBC) slide estimates, WBC determined by Leukopet, absolute heterophils, absolute lymphocytes, absolute monocytes, absolute eosinophils, or absolute basophils. Blood anticoagulated with EDTA had higher total solids than blood mixed with LH. For both anticoagulants, Leukopet-measured total WBC were consistently higher than blood film estimates. There were no subjective morphologic differences for WBC and no hemolysis observed in the samples. Thrombocyte clumping was prominent for LH blood samples and minimal for EDTA samples. These results reveal that LH and EDTA are both suitable anticoagulants for use in European starlings, and EDTA may be superior for diagnostic purposes or for qualitative evaluation of thrombocyte quantity.

THE PHARMACOKINETICS AND PHARMACODYNAMICS OF ORAL PONAZURIL IN THE TREATMENT OF SYSTEMIC ISOSPOROSIS IN PASSERINE BIRDS.

Systemic isosporosis, previously atoxoplasmosis, is a significant cause of mortality in juvenile passerine birds. Recommended treatment regimens are empiric and vary in efficacy. The goal of this study was to determine the pharmacokinetics and pharmacodynamics of ponazuril for treatment of systemic isosporosis. Ponazuril, diluted with water to create an oral suspension (50 mg/ml), was administered (100 mg/kg) to 72 European starlings (Sturnus vulgaris) by a single dose via direct oral gavage (n = 24), a single dose injected into superworm larvae (Zophobas morio; n = 24), or a daily dose mixed with commercial dog food to top-dress feed for 5 d (n = 24). Peak plasma concentrations were 5.84, 2.46, and 9.13 µg/ml for the direct gavage, injected larvae, and top-dressed feed groups, respectively. With repeated dosing, mean plasma concentrations from the top-dressed feed group were maintained between 8.12 to 13.11 µg/ml. Results suggested ponazuril at a dosage of 100 mg/kg administered via direct gavage or top-dressed feed, but not via injected larvae, would exceed the concentrations needed to inhibit merogony of other apicomplexan parasites in cell culture (5 µg/ml). To assess the pharmacodynamics of this dose, seven passerine birds, red-vented bulbuls (Pycnonotus cafer; n = 2), blue-grey tanager (Thraupis episcopus; n = 1), and red-capped cardinals (Paroaria gularis; n = 4), were identified as shedders of systemic Isospora spp. via fecal qPCR. Birds were then treated with ponazuril (100 mg/kg) daily on top-dressed feed for 14 d. Fecal shedding was assessed via qPCR for 6 wk from the initiation of treatment. Treatment was associated with reduction in proportions of fecal shedding during the treatment period and the week following treatment, but shedding resumed in all birds by the end of sampling. Results support that treatment of breeding birds with 100 mg/kg ponazuril could reduce the shedding of active oocysts and decrease risk of clinical infection in susceptible juveniles.