Haemoproteus paraortalidum in wild Dusky-legged Guans Penelope obscura (Galliformes: Cracidae) admitted to a Brazilian rehabilitation center: Morphological insights into blood and tissue stages

Haemosporidians are globally distributed parasites that exhibit high diversity and prevalence in Neotropical wild bird populations. Although long-term host-parasite coevolution often results in mild infections, disease outcomes may differ in naïve hosts, particularly in captive or managed environments where opportunities for pathogen spillover are increased. Haemoproteus (Parahaemoproteus) paraortalidum was originally described infecting captive-born Black-fronted Piping-Guans (Aburria jacutinga), an endangered cracid species maintained in a Brazilian wildlife rehabilitation centre. In the present study, we detected the same parasite in four out of eight Dusky-legged Guans (Penelope obscura) recently admitted to a rehabilitation center but originating from wild environments, thereby confirming the natural circulation of H. (P.) paraortalidum among Brazilian cracids. Morphological analyses of blood stages together with partial cytb gene sequencing corroborated species identity, and exoerythrocytic meronts were detected in cardiac tissue of one naturally infected individual. Although several nonspecific lesions were observed, none could be directly attributed to the presence of parasite tissue stages. The detection of exoerythrocytic meronts in a naturally infected host represents a rare finding and provides novel insights into the biology of H. (P.) paraortalidum. While pathogenicity was not demonstrated in this study, our results highlight the need for further investigations into the epidemiology and pathogenic potential of this parasite, particularly in vulnerable cracid species and in conservation contexts involving captivity and translocation.