RESUMO
Haemoproteid species have a wide global distribution, and they have been described in falcon species in several parts of the world. However, few studies in South America have focused on these birds. Haemoproteus spp. infections have been reported as the causative agents of serious histopathological changes, which can lead to the death of the host. Thus, this study aimed to molecularly and phylogenetically characterize Haemoproteus spp. in Caracara plancus, to characterize aspects of parasitism through clinical analysis and biochemical parameters, and to describe the histopathology of infection. To examine these aspects, 5 southern caracaras were examined clinically, and blood samples were collected. Blood smears were subsequently utilized in parasitemia calculations, PCR amplification, and serum biochemical investigations. Histological sections of the liver, kidneys, spleen, and heart were examined to check for possible histopathological changes. The birds showed clinical signs such as pallor and prostration that are consistent with Haemoproteus spp. infection. Moreover, the examination of the blood smears revealed 0.07% parasitemia in young gametocytes only. The PCR and sequencing results confirmed that the parasites belonged to Haemoproteus spp. The activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) enzymes, albumin, total serum proteins, and enzymatic urea were first described in C. plancus and serve as reference for future studies of bird species parasitized by Haemoproteus spp. Histopathology results showed signs of injury that were consistent with haemosporidian infection in the tissues of the analyzed organs. The present study is preliminary, and additional studies of Haemoproteus spp. infections in other bird species are needed to better understand the relationship between parasites and hosts, because despite the low parasitemia recorded, biochemical and histopathological changes in various organs were observed.