No host too tough: New records of Plasmodium huffi in competent avian hosts, including Brazilian vultures and falcons

Plasmodium huffi was first described in toucans of Brazil and was mistakenly believed to be a species exclusive to the order Piciformes. However, subsequent molecular and morphological studies conducted in red-legged seriemas, along with the diverse range of lineages identified in Anseriformes, Charadriiformes, Cathartiformes, Columbiformes, Galliformes, Pelecaniformes, Struthioniformes, Psittaciformes, and Passeriformes, have revealed that this parasite is, in fact, a generalist . Here, we provide new molecular and morphological data on P. huffi infecting previously unreported avian hosts in Brazil: one black vulture ( Coragyps atratus , Cathartiformes, sample size = 29) and one yellow-headed caracara ( Daptrius chimachima , Falconiformes, sample size = 6). Additionally, infections were detected in two red-legged seriemas ( Cariama cristata , Cariamiformes, sample size = 14), reinforcing the high susceptibility of the species to this parasite. Reports of haemosporidian infections in Cathartiformes are rare. To date, only Haemoproteus catharti , Plasmodium elongatum , and Leucocytozoon toddi have been documented in New World vultures—birds that are widely distributed and abundant across multiple ecosystems. This study marks the first report of haemosporidian infection in black vultures in South America. Although D. chimachima harbors a diverse and abundant haemosporidian community, this is the first record of P. huffi infecting a species within Falconiformes. These findings confirm that P. huffi is highly adapted to a broad range of avian hosts, which can sustain the infection and potentially transmit it to dipteran vectors, as evidenced by the presence of gametocytes in peripheral blood. Additionally, statistical comparisons of the parasite's morphometry across different hosts revealed high phenotypic plasticity, both within and between host species. • First report of Plasmodium huffi in black vultures in South America. • First record of P. huffi infecting a Falconiformes species. • P. huffi shows high host generalism across avian orders. • Morphological plasticity of P. huffi confirmed across different hosts.