Haemosporidian parasite infections in grouse and ptarmigan: prevalence and genetic diversity of blood parasites in resident Alaskan birds

Information regarding the prevalence and diversity of haemosporidian parasites in grouse and ptarmigan species is limited, with few recent studies and an almost complete lack of genetic data. Future climate warming predictions... [ view full abstract ]

Information regarding the prevalence and diversity of haemosporidian parasites in grouse and ptarmigan species is limited, with few recent studies and an almost complete lack of genetic data. Future climate warming predictions indicate the potential for an increase in the distribution and prevalence of blood parasites in northern regions, and baseline data on blood parasite infection in resident avian host species in Alaska and other northern regions is currently lacking. To better understand the current patterns of geographic range and host association of haemosporidian parasites in Alaskan tetraonids, and to determine the prevalence and genetic diversity of these parasites, we used molecular methods to screen 459 wing-tissue samples collected from grouse and ptarmigan species across Alaska for infection by Leucocytozoon, Haemoproteus, and Plasmodium. Infections were detected in 342 individuals (74.5%), with apparent prevalence of 53% for Leucocytozoon, 21% for Haemoproteus, and 9% for Plasmodium. Parasite prevalence varied by region, with different patterns observed between species groups (grouse versus ptarmigan). Leucocytozoon infection occurred more frequently in ptarmigan, whereas Haemoproteus was more common in grouse. Plasmodium infections were detected in grouse only. Analysis of haemosporidian DNA sequences revealed 23 unique parasite haplotypes, several of which were identical to lineages previously detected in other avian hosts. Phylogenetic analysis revealed close relationships between lineages from our study and those identified in Alaskan waterfowl for Haemoproteus and Plasmodium parasites. In contrast, Leucocytozoon lineages were structured strongly by host family. Our results provide some of the first genetic data for haemosporidians in grouse and ptarmigan species and important baseline information on the prevalence and diversity of blood parasites in a group of northern host species.