Hidden in plain sight: Morphological and molecular description of Plasmodium aramidis n. sp. in blood and tissues from Brazilian Wood Rails.

Abstract

The study of avian haemosporidians is hindered by the sampling bias of their hosts and the scarcity of robust species descriptions linking morphological, ecological, and molecular data. This is evidenced in our limited understanding of the haemosporidian diversity in the order Gruiformes. To date, only 14 haemosporidian species have been described in this diverse and globally distributed avian group. Here, we present morphological data of the ARACAJ01 cytb gene lineage and describe a new species: Plasmodium aramidis n. sp. This species was identified in five Grey-necked Wood Rails (Aramides cajaneus) rescued from the wild in Southeastern Brazil. We also propose a phylogenetic hypothesis based on the parasite's near-complete mitochondrial genome sequences. Histopathology indicates that P. aramidis n. sp. is pathogenic, evidenced by pulmonary lesions, such as edema and hemorrhage, as well as hepatic hemosiderosis, which was found in all individuals analyzed. Additionally, two out of the three individuals examined exhibited the presence of exoerythrocytic meronts within putative histiocytes and endothelial cells of the lungs, heart, and skeletal muscle. Plasmodium aramidis n. sp. appears to be a common parasite of A. cajaneus, but further studies are needed to identify additional hosts and to better understand their pathogenicity.