biostudies-literatureUnknown4Vieira LMCE<h4>Introduction</h4>Pathogens and parasites play a crucial role in shaping ecological and evolutionary processes, influencing the behavior, physiology, and survival of their hosts across diverse ecosystems. Despite their taxonomic and functional diversity, non-passerine birds remain underrepresented in pathogen/parasite ecological research, providing an opportunity to explore how their unique life histories influence host-parasite dynamics. Investigating the susceptibility of non-passerines to infections, particularly in relation to physiological stress indicators such as heterophil-to-lymphocyte (H/L) ratios and microhematocrit levels, offers valuable insights into the complex interplay between health state, environmental conditions, and disease dynamics.<h4>Methods</h4>We evaluated the occurrence of haemosporidian parasite (avian malaria) infections (Plasmodium spp. and Haemoproteus spp.) in individuals from six non-passerine bird species - Red-legged Seriema (Cariama cristata), Crested Caracara (Caracara plancus), Yellow-headed Caracara (<i>Daptrius chimachima</i>), Dusky-legged Guan (Penelope obscura), Gray-necked Wood-Rail (Aramides cajaneus), and Tropical Screech Owl (Megascops choliba) - that were admitted to the Wildlife Screening Center in Belo Horizonte, Minas Gerais, Brazil. We assessed whether blood-parasite infection occurrence was associated with hematological parameters (e.g. microhematocrit, H/L ratio), major injuries, age, body condition, season, co-occurrence of Trichomonas spp. infections, and presence of ectoparasites.<h4>Results</h4>Of the 75 individuals analyzed, 37% were infected with haemosporidian parasites (Plasmodium spp. and Haemoproteus spp. combined). Age was a significant predictor of haemosporidian infection, with adults exhibiting higher overall haemosporidian parasite occurrence (both Plasmodium spp. and Haemoproteus spp. together), likely due to age-related chronic infection accumulation or higher mortality among infected juveniles. Also, individuals infected with Haemoproteus spp. only showed elevated H/L ratios, suggesting a physiological response to infection, and were more frequently infected during the rainy season, likely reflecting optimal vector conditions. No significant associations were observed between blood-parasite infection occurrence and other factors such as physical condition, major injuries, co-occurring Trichomonas spp., or the presence of ectoparasites.<h4>Discussion</h4>These findings highlight the importance of considering physiological, environmental, and life-history factors when investigating malaria infections in non-passerine birds. By advancing our understanding of host-parasite interactions in these underrepresented species, this study contributes valuable knowledge to inform conservation, rehabilitation, and wildlife-management strategies for these less-studied birds.Frontiers in parasitology1568852https://www.ebi.ac.uk/biostudies/studies/S-EPMC12358355biostudies-literaturePhysiological, environmental, and life-history drivers of haemosporidian infections in non-passerine birds from a rehabilitation center.PMC12358355McGraw KJda Silva AVDAguiar de Souza Penha VVieira LMCEBraga EMfalsePhysiological, environmental, and life-history drivers of haemosporidian infections in non-passerine birds from a rehabilitation center.<h4>Introduction</h4>Pathogens and parasites play a crucial role in shaping ecological and evolutionary processes, influencing the behavior, physiology, and survival of their hosts across diverse ecosystems. Despite their taxonomic and functional diversity, non-passerine birds remain underrepresented in pathogen/parasite ecological research, providing an opportunity to explore how their unique life histories influence host-parasite dynamics. Investigating the susceptibility of non-passerines to infections, particularly in relation to physiological stress indicators such as heterophil-to-lymphocyte (H/L) ratios and microhematocrit levels, offers valuable insights into the complex interplay between health state, environmental conditions, and disease dynamics.<h4>Methods</h4>We evaluated the occurrence of haemosporidian parasite (avian malaria) infections (Plasmodium spp. and Haemoproteus spp.) in individuals from six non-passerine bird species - Red-legged Seriema (Cariama cristata), Crested Caracara (Caracara plancus), Yellow-headed Caracara (<i>Daptrius chimachima</i>), Dusky-legged Guan (Penelope obscura), Gray-necked Wood-Rail (Aramides cajaneus), and Tropical Screech Owl (Megascops choliba) - that were admitted to the Wildlife Screening Center in Belo Horizonte, Minas Gerais, Brazil. We assessed whether blood-parasite infection occurrence was associated with hematological parameters (e.g. microhematocrit, H/L ratio), major injuries, age, body condition, season, co-occurrence of Trichomonas spp. infections, and presence of ectoparasites.<h4>Results</h4>Of the 75 individuals analyzed, 37% were infected with haemosporidian parasites (Plasmodium spp. and Haemoproteus spp. combined). Age was a significant predictor of haemosporidian infection, with adults exhibiting higher overall haemosporidian parasite occurrence (both Plasmodium spp. and Haemoproteus spp. together), likely due to age-related chronic infection accumulation or higher mortality among infected juveniles. Also, individuals infected with Haemoproteus spp. only showed elevated H/L ratios, suggesting a physiological response to infection, and were more frequently infected during the rainy season, likely reflecting optimal vector conditions. No significant associations were observed between blood-parasite infection occurrence and other factors such as physical condition, major injuries, co-occurring Trichomonas spp., or the presence of ectoparasites.<h4>Discussion</h4>These findings highlight the importance of considering physiological, environmental, and life-history factors when investigating malaria infections in non-passerine birds. By advancing our understanding of host-parasite interactions in these underrepresented species, this study contributes valuable knowledge to inform conservation, rehabilitation, and wildlife-management strategies for these less-studied birds.2025-01-01T00:00:00Z20252026-04-13T17:11:40.43Z2026-04-07T13:34:26.342ZS-EPMC123583554083159610.3389/fpara.2025.1568852