Background: Blood parasites belonging to the Apicomplexa, Trypanosomatidae and Filarioidea are widespread in birds and have been studied extensively. Microscopical examination (ME) of stained blood films remains the gold standard method for the detection of these infections in birds, particularly because co-infections predominate in wildlife. None of the available molecular tools can detect all co-infections at the same time, but ME provides opportunities for this to be achieved. However, fixation, drying and staining of blood films as well as their ME are relatively time-consuming. This limits the detection of infected hosts during fieldwork when captured animals should be released soon after sampling. It is an obstacle for quick selection of donor hosts for parasite experimental, histological and other investigations in the field. This study modified, tested and described the buffy coat method (BCM) for quick diagnostics (~ 20 min/sample) of avian blood parasites.Methods: Blood of 345 birds belonging to 42 species was collected, and each sample was examined using ME of stained blood films and the buffy coat, which was examined after centrifugation in capillary tubes and after being transferred to objective glass slides. Parasite detection using these methods was compared using sensitivity, specificity, positive and negative predictive values and Cohen’s kappa index.Results: Haemoproteus,Leucocytozoon,Plasmodium, microfilariae,TrypanosomaandLankesterellaparasites were detected. BCM had a high sensitivity (> 90%) and specificity (> 90%) for detection ofHaemoproteusand microfilariae infections. It was of moderate sensitivity (57%) and high specificity (> 90%) forLankesterellainfections, but of low sensitivity (20%) and high specificity (> 90%) forLeucocytozooninfections.TrypanosomaandPlasmodiumparasites were detected only by BCM and ME, respectively. According to Cohen’s kappa index, the agreement between two diagnostic tools was substantial forHaemoproteus(0.80), moderate forLankesterella(0.46) and fair for microfilariae andLeucocytozoon(0.28) infections.Conclusions: BCM is sensitive and recommended as a quick and reliable tool to detectHaemoproteus,Trypanosomaand microfilariae parasites during fieldwork. However, it is not suitable for detection of species ofLeucocytozoonandPlasmodium. BCM is a useful tool for diagnostics of blood parasite co-infections. Its application might be extended to studies of blood parasites in other vertebrates during field studies.

Background: Blood parasites have been the subject of much research, with numerous reports of the presence of microfilariae in the peripheral blood (circulating microfilariae) of birds belonging to many orders. Current limitations in molecular characterization methods and species identification using morphological characters of circulating microfilariae are major obstacles to improving our understanding the biology of Filarioidea species, particularly in wildlife. The aim of this study was to partially fill these gaps, with particular emphasis on morphological features of microfilariae, which are the most readily accessible stages of these pathogens.Methods: Peripheral blood samples of 206 birds belonging to generaAcrocephalus(five species) andSylvia(five species) were examined using the buffy coat method to process the blood samples for the presence of microfilariae. Positive birds were dissected to collect adult nematodes. Microfilariae and adult nematodes were described, and sequences of their mitochondrial cytochromecoxidase subunit I and nuclear28SrDNA gene fragments were obtained and used for molecular characterization and Bayesian phylogenetic inferences.Results: Overall prevalence of microfilariae was 2.9%. Microfilariae were found in the blood samples from six birds (2Acrocephalus scirpaceusand 1 each ofA. arundinaceus,Sylvia atricapilla,S. borinandS. curruca), which were dissected. All parasite species observed were new.Eufilaria acrocephalusisp. n. andEufilaria sylviaesp. n. were present in subcutaneous, peritracheal and periesophageal connective tissues inA. scirpaceusandS. borin,respectively.Splendidofilaria bartlettisp. n. was found in finger joins ofS. atricapilla.Illustrations of microfilariae and adult nematodes are shown, and morphological and phylogenetic analyses identified the DNA barcode haplotypes that are associated with these species. Phylogenetic analysis places the parasites of different genera in different closely related clades.Conclusions: Adult nematode morphological characters, which have been traditionally used in the taxonomy of Filarioidea species, have a phylogenetic value. Importantly, in our study parasites of different genera were readily distinguishable based on the morphology of their microfilariae. The link between molecular and morphology data requires more study in Filarioidea species research, particularly because this approach provides new knowledge on species identity using only readily accessible blood stages (microfilariae), thereby avoiding host dissection and thus minimizing harm to wildlife during research.Graphical

Avian blood parasites are remarkably diverse and frequently occur in co-infections, which predominate in wildlife. This makes wildlife pathogen research challenging, particularly if they belong to closely related groups, resulting in diagnostic problems and poor knowledge about such infections as well as the patterns of their co-occurrence and interactions. This is particularly true due to the periodicity (circadian rhythms) of parasitemia, which means that different parasitemia and parasite stages might be found throughout the day. We analysed blood samples from a Eurasian blackbird (Turdus merula) and a Song thrush (Turdus philomelos). This study aimed to describe a new avian Lankesterella species and molecularly characterize and redescribe Splendidofilaria mavis, a common avian filarioid nematode. Additionally, it was possible to investigate the circadian rhythms of the avian blood parasites belonging to Plasmodium, Haemoproteus, Leucocytozoon, and Trypanosoma, which occurred in co-infection in the same avian host individuals. Different circadian rhythms were seen in different parasites, with Plasmodium sp. peaks occurring at midday, Leucocytozoon spp. peaks mainly during the evening and night, and Trypanosoma spp. and microfilariae peaks at midnight. No periodicity was seen in Haemoproteus and Lankesterella species infections. The time of parasitemia peaks most likely coincides with the time of vectors’ activity, and this should be beneficial for transmission. Knowledge about the circadian rhythms is needed for better understanding patterns in host-parasite interactions and disease transmission.

The cestode fauna in shrews of the genus Sorex from the European region consists of seventeen species. Twelve cestode species have broad Palearctic distributions, three belong to the Western-Asian-European faunistic complex, and only two are endemic to the European zone. Postglacial expansion into the European territory resulted in geographic colonization by sixteen species. The large number of cestode species with transpalearctic ranges, as well as paleontological data indicating a nearly complete faunal turnover for species of Sorex in the Pleistocene, suggests that these parasites are more ancient than the assemblage of contemporary hosts in which they now occur, and thus represent ecological relicts. We suggest that origins of the cestode fauna pre-date those of the modern fauna of its hosts, and that initial formation and radiation occurred not later than the Pliocene. In the current review, we outline testable hypotheses to explore the structure, history and development of this fauna which appears limited to species of Sorex.

The helminth fauna and helminth infection in two species of Sorex shrews (S. Araneus and S. Minutus) were studied in various parts of Lithuania. Altogether 34 species of helminths, representing trematodes (5 species), cestodes (15) and nematodes (14), were recorded. The overall prevalence of infection of the common shrew (S. Araneus) was 92.1% and that of the pigmy shrew (S. Minutus) was 91.1%. Most shrews were infected with cestodes (82.0% in S. araneus and 81.3% in S. Minutus) and nematodes (83.9% and 85.4%, respectively), fewer with trematodes (21.1% and 6.3%, respectively). The total number of helminth species and the number of species per host were higher in S. Araneus. High prevalence of infection in shrews shows that these animals play a significant role in spreading of helminth species, especially cestodes and nematodes. Moreover, they are paratenic hosts of parasites of other animals, which are important to farming.