A Safe and Effective Atovaquone-Proguanil Therapeutic Protocol for the Treatment of Avian Malaria by Plasmodium relictum in Snowy Owl (Bubo scandiacus)

SIMPLE SUMMARY: This study assessed the efficacy of treating snowy owls naturally infected by Plasmodium relictum with atovaquone (AV) and proguanil (PH). AV/PH was administered at 10/4 mg/kg/day for three days, repeated a week later. Results showed the treatment was effective in clearing the parasite from the birds’ blood, with no relapses observed. Additionally, hematological improvements were noted, suggesting recovery. No significant adverse effects were observed, indicating the safety of the treatment. This study highlights the potential of AV/PH as a treatment option for avian malaria in unconventional or endangered bird species. ABSTRACT: Avian malaria is a re-emerging threat to avian species worldwide. It is sustained by several protozoan species belonging to the genus Plasmodium, mainly Plasmodium relictum. The even wider diffusion of the disease, probably because of the increase in the areas covered by their mosquito vectors, may pose new risks for avian species lacking natural resistance (especially those from artic or sub-artic environments) or those hosted in structures like zoos and wildlife rescue centers. With that premise, this study describes the efficacy and safety of a therapeutic protocol to treat avian malaria in three snowy owls (Bubo scandiacus) hosted in a wildlife rescue center in Apulia, south of Italy, and affected by avian malaria by P. relictum. The protocol consisted of administering 10/4 mg/kg atovaquone/proguanil per os once a day for three consecutive days, repeating this seven days later. Seven days after the end of the treatment, P. relictum was not detected in the birds’ blood and no adverse effects were observed during the 60 days of monitoring after the end of the treatment. Therefore, a therapeutic regimen of 10/4 mg/kg/day may be considered safe and effective in a valuable and endangered species such as B. scandiacus.