Search Results (4)

Haemoproteus parasites (Apicomplexa, Haemosporida) are widespread pathogens of birds, with a rich genetic (about 1900 lineages) and morphospecies (178 species) diversity. Nonetheless, their life cycles are poorly understood. The exo-erythrocytic stages of three Haemoproteus majoris (widespread generalist parasite) lineages have been previously reported, each in a different bird species. We aimed to further study and compare the development of five H. majoris lineages—hCCF5, hCWT4, hPARUS1, hPHSIB1, and hWW2—in a wider selection of natural avian hosts. A total of 42 individuals belonging to 14 bird species were sampled. Morphospecies and parasitemia were determined by microscopy of blood films, lineages by DNA-barcoding a 478 bp section of the cytochrome b gene, and exo-erythrocytic stages by histology and chromogenic in situ hybridization. The lineage hCWT4 was morphologically characterized as H. majoris for the first time. All lineage infections exclusively featured megalomeronts. The exo-erythrocytic stages found in all examined bird species were similar, particularly for the lineages hCCF5, hPARUS1, and hPHSIB1. Megalomeronts of the lineages hWW2 and hCWT4 were more similar to each other than to the former three lineages. The kidneys and gizzard were most often affected, followed by lungs and intestines; the site of development showed variation depending on the lineage. Full article

Avian haemosporidian parasites (Haemosporida, Apicomplexa) are globally distributed and infect birds of many orders. These pathogens have been much investigated in domestic and wild passeriform birds, in which they are relatively easy to access. In birds belonging to other orders, including owls (order Strigiformes), these parasites have been studied fragmentarily. Particularly little is known about the exo-erythrocytic development of avian haemosporidians. The goal of this study was to gain new knowledge about the parasites infecting owls in Europe and investigate their exo-erythrocytic stages. Tissue samples of 121 deceased owls were collected in Austria and Lithuania, and examined using polymerase chain reactions (PCR), histology, and chromogenic in situ hybridization (CISH). PCR-based diagnostics showed a total prevalence of 73.6%, revealing two previously unreported Haemoproteus and five novel Leucocytozoon lineages. By CISH and histology, meronts of several Leucocytozoon lineages (lASOT06, lSTAL5, lSTAL7) were discovered in the brains, heart muscles, and kidneys of infected birds. Further, megalomeronts of Haemoproteus syrnii (lineage hSTAL2) were discovered. This study contributes new knowledge to a better understanding of the biodiversity of avian haemosporidian parasites infecting owls in Europe, provides information on tissue stages of the parasites, and calls for further research of these under-investigated pathogens relevant to bird health. Full article

Haemoproteus species are widespread avian blood parasites belonging to Haemoproteidae (Haemosporida). Blood stages of these pathogens have been relatively well-investigated, though exo-erythrocytic (tissue) stages remain unidentified for the majority of species. However, recent histopathological studies show that haemoproteins markedly affect bird organs during tissue merogony. This study investigated the exo-erythrocytic development of Haemoproteus (Parahaemoproteus) attenuatus (lineage hROBIN1), the common parasite of flycatchers (Muscicapidae). Naturally infected European robins Erithacus rubecula were examined. Parasite species and lineage were identified using microscopic examination of blood stages and DNA sequence analysis. Parasitaemia intensity varied between 0.8 and 26.5% in seven host individuals. Organs of infected birds were collected and processed for histological examination. Tissues stages (meronts) were seen in six birds and were present only in the lungs. The parasites were usually located in groups and were at different stages of maturation, indicating asynchronous exo-erythrocytic development. In most parasitized individuals, 100 meronts were observed in 1 cm² section of lungs. The largest meronts reached 108 µm in length. Mature meronts contained numerous roundish merozoites of approximately 0.8 µm in diameter. Megalomeronts were not observed. Massive merogony and resulting damage of lungs is a characteristic feature during H. attenuatus infections and might occur in related parasite lineages, causing haemoproteosis. Full article

Species of Haemoproteus (Haemoproteidae, Haemosporida) are common bird pathogens. Recent molecular studies combined with histopathology research have reported development of megalomeronts of these parasites in various organs, sometimes resulting in the death of the avian host. Five Common starlings (Sturnus vulgaris) were found naturally infected with Haemoproteus pastoris lineage hLAMPUR01. The parasite was identified using microscopic examination of blood films and DNA sequences. Infected bird organs were investigated histologically for (i) the presence of exo-erythrocytic stages and (ii) the patterns of development (morphology and localization) in different host individuals. For the first time, megalomeronts of Haemoproteus parasites were seen developing in the brain, while numerous others at different stages of maturation were found in the intestine, pancreas, kidneys, lungs, esophagus, spleen, gizzard, and trachea. Megalomeronts were predominantly roundish or oval, up to 800 μm, they were surrounded by a capsular-like wall and developed asynchronously in the same bird individual. After megalomeront maturation and rupture, a massive infiltration of blood cells occurred, indicating the hemorrhagic processes. Review of available data showed that different Haemoproteus species produce markedly different megalomeronts, morphology of which can probably be predicted using phylogenetic analysis based on partial sequences of cytochrome b gene. Full article