Tolerability of Atovaquone-Proguanil Application in Common Buzzard Nestlings

Abstract

Differences in drug tolerability among vertebrate groups and species can create substantial challenges for wildlife and ex situ conservation programmes. Knowledge of tolerance in the use of new drugs is, therefore, important to avoid severe toxicity in species, which are both commonly admitted in veterinary clinics and are of conservation concern. Antimalarial drugs have been developed for use in human medicine, but treatment with different agents has also long been used in avian medicine, as haemosporidian infections play a major role in many avian species. This study investigates the effects of the application of atovaquone-proguanil (Malarone^®, GlaxoSmithKline) in common buzzards (Buteo buteo). The potential effects of treatment on body condition, growth rate, and chemical blood parameters of nestlings were assessed. All individuals survived the treatment, and no effects on body condition, growth rate, and chemical blood parameters were observed. Our results suggest the tolerability of Malarone^® in common buzzards at a single dose of on average 11 mg/kg body weight. For its safe use, we recommend further studies to determine pharmacokinetics in different avian species as well as to assess the effects of repeated treatment.

Keywords: Buteo buteo; Malarone; avian malaria; blood chemistry; drug tolerance; haemosporidian parasites.

Figure 1

Effects of treatment and control on body condition and growth rate. Visualisation of the predicted values of (A) body condition and (B) growth rate from linear mixed models testing the effect of treatment (control, Malarone^®, and water) on these two fitness proxies. Black dots represent mean estimates for each of the treatment groups. Main boxplots represent standard deviations, and error bars indicate 95% confidence intervals. See Table 1 for statistical comparison of treatment groups.

Figure 2

Regression analyses for weight and wing length. Visualisation of regression analyses for weight and wing length of control, Malarone^®-, and water-treated nestlings (solid line) in comparison to the reference data of common buzzards [20] (dotted black line) for female (󠇂♀, n = 136) and male (♂, n = 163) individuals. Circles represent values at first sampling, triangles at second sampling. R² represents the proportion of variance explained by both fixed and random effects in each model.

Figure 3

Mean differences of eleven parameters among treatment and control. Visualisation of mean differences in nestling age at sampling (A), body condition index (B), and blood chemistry parameters (C−K) among four groups: “Pre−Control”, “Post−Control”, “Pre−Mal”, and “Post−Mal”. Black dots represent mean estimates for each of the treatment groups. Main boxplots represent standard deviations, and error bars indicate 95% confidence intervals. Open circles represent raw data for each individual. See Table S2 for statistical comparisons of parameters (B−K).