Haemoproteus ilanpapernai n. sp. (Apicomplexa, Haemoproteidae) in Strix seloputo from Singapore: morphological description and reassignment of molecular data

A fatal case of a captive snowy owl (Bubo scandiacus) with Haemoproteus infection in Japan

Parasites of the genus Haemoproteus are vector-borne avian haemosporidia commonly found in bird species of the world. Haemoproteus infections are typically considered relatively benign in birds. However, some Haemoproteus species cause severe disease and mortality, especially for captive birds removed from their original habitat. In September 2018, a captive 15-year-old snowy owl (Bubo scandiacus), kept in a zoological garden of Japan, died subacutely after presenting leg dysfunction. This case showed significantly low PCV and elevated AST, ALT, CK, and LDH values. Many megalomeronts with prominent morphological characteristics of Haemoproteus were observed in the left leg muscles. Those megalomeronts exhibited multilocular structures and were internally filled with merozoites. A new lineage of Haemoproteus was detected by subsequent PCR for the cytochrome b (cytb) gene of avian haemosporidia from DNA extracted from several organ tissues. The detected lineage was classified in the subgenus Parahaemoproteus and was similar to those from the wild birds inhabiting the region including the study area, suggesting that this snowy owl likely acquired its infection from wild birds. This is the first report of a fatal case of a captive bird with a locally transmitted Haemoproteus infection in Japan. We considered the pathogenicity of this infection in conjunction with the clinical course and hematology results. We surmise that snowy owls may be particularly susceptible to infection with Haemoproteus parasites, and warming northern temperatures may exacerbate the overall health of these and other high latitude birds. Further research into the prevalence of Haemoproteus in wild birds near zoological gardens and potential biting midge vectors is necessary for the ex situ conservation of introduced birds.

Molecular diversity and coalescent species delimitation of avian haemosporidian parasites in an endemic bird species of South America

Haemoproteus spp. and Plasmodium spp. are blood parasites that occur in birds worldwide. Identifying the species within this group is complex, especially in wild birds that present low parasitemia when captured, making morphological identification very difficult. Thus, the use of alternative tools to identify species may be useful in the elucidation of the distribution of parasites that circulate in bird populations. The objectives of this study were to determine the prevalence and parasitemia of the genera Plasmodium and Haemoproteus in Tachyphonus coronatus in the Atlantic Forest, Brazil, and to evaluate the molecular diversity, geographic distribution, and specificity of these parasites based on coalescent species delimitation methods. Microscopic analysis, PCR, cyt b gene sequencing, phylogenetic analysis and coalescent species delimitation using single-locus algorithms were performed (Poisson tree process (PTP) and multi-rate Poisson tree process (MPTP) methods). The analyses were performed in 117 avian host individuals. The prevalence was 55.5% for Plasmodium and 1.7% for Haemoproteus, with a mean parasitemia of 0.06%. Twenty-five Plasmodium and two Haemoproteus lineages were recovered. The MPTP method recovered seven different evolutionarily significant units (ESUs) of Plasmodium and one of Haemoproteus, whereas PTP presented fourteen ESUs of Plasmodium and one of Haemoproteus. The MPTP was more consistent with current taxonomy, while PTP overestimated the number of lineages. These ESUs are widely distributed and have already been found in 22 orders of birds that, all together, inhabit every continent, except Antarctica. The computational methods of species delimitation proved to be effective in cases where the classification of Haemosporida based just on morphology is insufficient.

Evolutionary ecology, taxonomy, and systematics of avian malaria and related parasites

Haemosporidian parasites of the genera Plasmodium, Leucocytozoon, and Haemoproteus are one of the most prevalent and widely studied groups of parasites infecting birds. Plasmodium is the most well-known haemosporidian as the avian parasite Plasmodium relictum was the original transmission model for human malaria and was also responsible for catastrophic effects on native avifauna when introduced to Hawaii. The past two decades have seen a dramatic increase in research on avian haemosporidian parasites as a model system to understand evolutionary and ecological parasite-host relationships. Despite haemosporidians being one the best studied groups of avian parasites their specialization among avian hosts and variation in prevalence amongst regions and host taxa are not fully understood. In this review we focus on describing the current phylogenetic and morphological diversity of haemosporidian parasites, their specificity among avian and vector hosts, and identifying the determinants of haemosporidian prevalence among avian species. We also discuss how these parasites might spread across regions due to global climate change and the importance of avian migratory behavior in parasite dispersion and subsequent diversification.

Haemoproteus in barn and collared scops owls from Thailand

The barn owl (BO) and the collared scops owl (CSO) are common nocturnal raptors throughout Thailand. Blood samples from 23 adult BOs and 14 CSOs were collected and processed for complete blood cell counts and parasite morphological examinations. Two Haemoproteus-positive samples were processed for ultrastructural observation. Polymerase chain reaction (PCR) analysis for a partial cytochrome b gene (cytb) from Haemoproteus was performed in all samples. Haemoproteus presence detected by light microscopy was lower than that detected by PCR (30.4% and 34.8%, respectively, in BO; and 50.0% and 78.6%, respectively, in CSO). Comparative hematology revealed that Haemoproteus-positive BOs had higher mean cell hemoglobin concentration, total leukocyte, absolute heterophil, basophil, and monocyte counts than Haemoproteus-negative BOs, but no significant differences between Haemoproteus-negative and -positive CSOs. Monocyte ultrastructure analysis revealed a role in the elimination of gametocytes. Morphologically, the Haemoproteus in 3 BOs and 6 CSOs were identified as H. noctuae, while that in 1 CSO was identified as H. syrnii. Phylogenetic analysis indicated the Haemoproteus spp. in 8 BOs and 7 CSOs were not closely related to H. noctuae or H. syrnii, and the cytb of 2 CSOs was that of H. syrnii. These results should be useful for study of Haemoproteus.