Recent studies show that host switching is much more frequent than originally believed and constitutes an important driver in evolution of host-parasite associations. However, its frequency and ecological mechanisms at the population level have been rarely investigated. We address this issue by analyzing phylogeny and population genetics of an extensive sample, from a broad geographic area, for commonly occurring parasites of the genus Eimeria within the abundant rodent genera Apodemus, Microtus and Myodes, using two molecular markers. At the most basal level, we demonstrate polyphyletic arrangement, i.e. multiple origin, of the rodent-specific clusters within the Eimeria phylogeny, and strong genetic/phylogenetic structure within these lineages determined at least partially by specificities to different host groups. However, a novel and the most important observation is a repeated occurrence of host switches among closely related genetic lineages which may become rapidly fixed. Within the studied model, this phenomenon applies particularly to the switches between the eimerians from Apodemus flavicollis/Apodemus sylvaticus and Apodemus agrarius groups. We show that genetic differentiation and isolation between A. flavicollis/A. sylvaticus and A. agrarius faunas is a secondary recent event and does not reflect host-parasite coevolutionary history. Rather, it provides an example of rapid ecology-based differentiation in the parasite population.

• Klíčová slova
• Coevolution, Ecological fitting, Host specificity, Host switching, Parasite, Rodent,
• MeSH
• biodiverzita * MeSH
• časové faktory MeSH
• Coccidia klasifikace   genetika   fyziologie   MeSH
• fylogeneze MeSH
• haplotypy genetika   MeSH
• hostitelská specificita * MeSH
• interakce hostitele a parazita * genetika   MeSH
• Murinae parazitologie   MeSH
• populační genetika MeSH
• zeměpis MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Mastomys natalensis-borne mammarenaviruses appear specific to subspecific M. natalensis taxa rather than to the whole species. Yet mammarenaviruses carried by M. natalensis are known to spill over and jump hosts in northern sub-Saharan Africa. Phylogeographic studies increasingly show that, like M. natalensis, small mammals in sub-Saharan Africa are often genetically structured into several subspecific taxa. Other mammarenaviruses may thus also form virus-subspecific host taxon associations. To investigate this, and if mammarenaviruses carried by M. natalensis in southern Africa are less prone to spill-over, we screened 1225 non-M. natalensis samples from Tanzania where many small mammal taxa meet. We found mammarenavirus RNA in 6 samples. Genetic/genomic characterisation confirmed they were not spill-over from M. natalensis. We detected host jumps among rodent tribe members and an association between mammarenaviruses and subspecific taxa of Mus minutoides and Grammomys surdaster, indicating host genetic structure may be crucial to understand virus distribution and host specificity.

• Klíčová slova
• Berega virus, Comparative phylogeography, Grammomys surdaster, Host genetic structure, Host jump, Host specificity, Mus minutoides, Ngerengere virus, Songea virus, Spill-over,
• MeSH
• Arenaviridae * genetika   MeSH
• fylogeografie MeSH
• hostitelská specificita MeSH
• Murinae MeSH
• nemoci hlodavců * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Tanzanie MeSH

Interplay between conserved host specificity and occasional host switches is an important process determining the evolution of host-parasite systems. Here, we address the dynamics of host switches at the population level in rodent-associated Eimeria. Focusing mainly on two ecologically similar host groups, Murinae and Arvicolinae, we show that the Eimeria infecting those hosts form a complex system of many genetic lineages with different host specificities. The broad geographic distribution of lineages indicates that they are well-established genetic forms which retained their host specificities while spreading across large geographic areas. We also demonstrate that genetic structure is only partially reflected by morphological traits.

• Klíčová slova
• Arvicolinae, Coccidia, Coevolution, Host specificity, Murinae, Phylogeny,
• MeSH
• Arvicolinae MeSH
• Eimeria * MeSH
• fylogeneze MeSH
• hostitelská specificita MeSH
• interakce hostitele a parazita MeSH
• lidé MeSH
• Murinae MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Generalist parasites have the capacity to infect multiple hosts. The temporal pattern of host specificity by generalist parasites is rarely studied, but is critical to understanding what variables underpin infection and thereby the impact of parasites on host species and the way they impose selection on hosts. Here, the temporal dynamics of infection of four species of freshwater mussel by European bitterling fish (Rhodeus amarus) was investigated over three spawning seasons. Bitterling lay their eggs in the gills of freshwater mussels, which suffer reduced growth, oxygen stress, gill damage and elevated mortality as a result of parasitism. The temporal pattern of infection of mussels by European bitterling in multiple populations was examined. Using a Bernoulli Generalized Additive Mixed Model with Bayesian inference it was demonstrated that one mussel species, Unio pictorum, was exploited over the entire bitterling spawning season. As the season progressed, bitterling showed a preference for other mussel species, which were inferior hosts. Temporal changes in host use reflected elevated density-dependent mortality in preferred hosts that were already infected. Plasticity in host specificity by bitterling conformed with the predictions of the host selection hypothesis. The relationship between bitterling and their host mussels differs qualitatively from that of avian brood parasites.

• Klíčová slova
• Brood parasite, Host–parasite co-evolution, Oviposition, Spawning site, Superparasitism,
• MeSH
• Bayesova věta MeSH
• Cyprinidae MeSH
• hostitelská specificita * MeSH
• interakce hostitele a parazita * MeSH
• paraziti MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Protozoan parasites of the Eimeria genus have undergone extensive speciation and are now represented by a myriad of species that are specialised to different hosts. These species are highly host-specific and usually parasitise single host species, with only few reported exceptions. Doubts regarding the strict host specificity were frequent in the original literature describing coccidia parasitising domestic turkeys. The availability of pure characterised lines of turkey and chicken Eimeria species along with the recently developed quantitative PCR identification of these species allowed to investigate the issue of host specificity using well-controlled cross-transmission experiments. Seven species of gallinaceous birds (Gallus gallus, Meleagris gallopavo, Alectoris rufa, Perdix perdix, Phasianus colchicus, Numida meleagris and Colinus virginianus) were inoculated with six species and strains of turkey Eimeria and six species of chicken coccidia and production of oocysts was monitored. Turkey Eimeria species E. dispersa, E. innocua and E. meleagridis could complete their development in the hosts from different genera or even different families. Comparison of phylogenetic positions of these Eimeria species according to 18S rDNA and COI showed that the phylogeny cannot explain the observed patterns of host specificity. These findings suggest that the adaptation of Eimeria parasites to foreign hosts is possible and might play a significant role in the evolution and diversification of this genus.

• Klíčová slova
• Chicken, Coccidia, Eimeria, Host specificity, Turkey,
• MeSH
• Eimeria klasifikace   fyziologie   MeSH
• fylogeneze * MeSH
• Galliformes * MeSH
• hostitelská specificita * MeSH
• kokcidióza parazitologie   veterinární   MeSH
• nemoci drůbeže parazitologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Lankesterella parasites are blood coccidians that have recently gained attention as their records in common passerine species emerge. To date, their occurrence has been molecularly confirmed in several passerine genera, mainly among members of the families Paridae and Acrocephalidae. Despite their relatively high prevalence in some host populations, their life cycles remain unclear, mosquitoes or mites being the proposed vectors. The aim of this study was to reveal Lankesterella host specificity, focusing mainly on parasites of tit and warbler species (families Paridae and Acrocephalidae). We have determined the 18S rRNA gene sequences of Lankesterella from 35 individuals belonging to eight different host species. Phylogenetic analysis revealed that passerine Lankesterella are host-specific, with specificity at the host genus or species level. Besides Lankesterella, Isospora sequences were obtained from avian blood as well, pointing out the need for barcoding.

• Klíčová slova
• Acrocephalus, Avian parasites, Cyanistes, Parus, Poecile, Sturnus,
• MeSH
• Apicomplexa * MeSH
• Coccidia * genetika   MeSH
• Eucoccidiida * MeSH
• fylogeneze MeSH
• hostitelská specificita MeSH
• lidé MeSH
• Passeriformes * parazitologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Acanthocephalans of the genus Bolbosoma Porta, 1908 are trophically transmitted parasites that infect marine mammals (mostly cetaceans and less frequently pinnipeds) worldwide. There are 12 species currently considered as valid; however, most records lack information on the maturity stage of the specimens. This, coupled with the scarce phylogenetic information available, hinders a correct understanding of their patterns of host specificity, evolutionary history, and taxonomy. A particularly intriguing case is that of Bolbosoma vasculosum (Rudolphi, 1819), which has been frequently reported in odontocetes but rarely as an adult, having been suggested to be synonymous with Bolbosoma capitatum (von Linstow, 1880). METHODS: We used a comprehensive approach to investigate the concept of Bolbosoma. First, we conducted a bibliographic review of records of Bolbosoma spp. to clarify which are the final hosts for each species. We paid particular attention to B. vasculosum, using morphological and molecular analyses to compare it with B. capitatum. Second, we characterized the complete mitochondrial genome of Bolbosoma balaenae (Gmelin, 1790), Bolbosoma turbinella (Diesing, 1851), B. capitatum, and B. vasculosum. Then, we reconstructed the phylogenetic relationships of Bolbosoma spp. and related taxa using full mitochondrial genomes (or only cox1 when full mitogenomes were unavailable) and nuclear ribosomal genes (18S and 28S). RESULTS: Bolbosoma spp. exhibit high specificity for cetaceans, with no confirmed records of adult specimens in other host groups. Within this genus, B. vasculosum appears to be conspecific with B. capitatum based on both morphological and molecular evidence. This species shows high affinity to odontocetes, while the remaining species are specific to mysticetes. Phylogenetic analyses showed strong support for the monophyly of Bolbosoma spp., which appeared as sister taxa to Corynosoma spp. and Andracantha spp.. The resulting topology aligns with the patterns of specificity indicated by host records, revealing two distinct clades for species specific to odontocetes and mysticetes, respectively. CONCLUSIONS: The phylogenetic relationships obtained support the hypothesis that the association of Bolbosoma spp. with cetaceans originated through a host-switching event from aquatic birds.

• Klíčová slova
• Bolbosoma, 18S rDNA, 28S rDNA, Acanthocephala, Cetaceans, Host-specificity, Mitogenome, Systematics,
• MeSH
• Acanthocephala * klasifikace   genetika   fyziologie   anatomie a histologie   MeSH
• Cetacea parazitologie   MeSH
• fylogeneze * MeSH
• genom mitochondriální MeSH
• hostitelská specificita * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Bats are recognized as key reservoir hosts for a variety of trypanosomes, yet their full diversity and host associations remain underexplored in Africa. In this study, we investigated the diversity and phylogenetic relationships of trypanosomes infecting bats in Uganda and the Central African Republic (CAR) using molecular tools. A total of 22 distinct genotypes were identified, clustering into seven well-supported phylogroups, including known species such as Trypanosoma dionisii, T. livingstonei, T. vespertilionis, and T. erneyi, alongside several novel lineages. Notably, T. erneyi was restricted to Mops condylurus, reaffirming its narrow host specificity. Phylogenetic analyses revealed substantial intraspecific diversity in T. livingstonei and T. vespertilionis, suggesting potential cryptic species, while T. dionisii exhibited limited genetic divergence across a broad geographic range. Intriguingly, a unique and highly diverse phylogroup was detected exclusively in fruit bats (Pteropodidae) from Uganda, closely related to the Australian T. teixeirae, and likely represents a novel species. The absence of trypanosomes in fruit bats from CAR, despite similar sampling effort, hints at ecological or evolutionary factors shaping parasite distribution. Our findings expand the current knowledge of bat-trypanosome diversity and highlight the importance of African bat populations in understanding the evolutionary dynamics of trypanosomes.

• Klíčová slova
• African Chiroptera, Bat trypanosomes, Host specificity, Phylogenetic diversity,
• MeSH
• Chiroptera * parazitologie   MeSH
• fylogeneze MeSH
• genetická variace * MeSH
• genotyp MeSH
• hostitelská specificita * MeSH
• Trypanosoma * genetika   klasifikace   izolace a purifikace   MeSH
• trypanozomiáza * veterinární   parazitologie   epidemiologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Středoafrická republika epidemiologie   MeSH
• Uganda MeSH

Myxobolus pseudodispar Gorbunova, 1936 (Myxozoa) is capable of infecting and developing mature myxospores in several cyprinid species. However, M. pseudodispar isolates from different fish show up to 5% differences in the SSU rDNA sequences. This is an unusually large intraspecific difference for myxozoans and only some of the muscle-dwelling myxozoan species possess such a high genetic variability. We intended to study the correlation between the host specificity and the phylogenetic relationship of the parasite isolates, and to find experimental proof for the putatively wide host range of M. pseudodispar with cross-infection experiments and phylogenetic analyses based on SSU rDNA. The experimental findings distinguished 'primary' and less-susceptible 'secondary' hosts. With some exceptions, M. pseudodispar isolates showed a tendency to cluster according to the fish host on the phylogenetic tree. Experimental and phylogenetic findings suggest the cryptic nature of the species. It is likely that host-shift occurred for M. pseudodispar and the parasite speciation in progress might explain the high genetic diversity among isolates which are morphologically indistinguishable.

• Klíčová slova
• Cyprinidae, Myxozoa, SSU rDNA, cross-infection, host specificity, molecular phylogeny,
• MeSH
• fylogeneze MeSH
• genetická variace * MeSH
• hostitelská specificita * MeSH
• Myxobolus genetika   fyziologie   MeSH
• nemoci ryb parazitologie   MeSH
• parazitární nemoci u zvířat parazitologie   MeSH
• ribozomální DNA genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ribozomální DNA MeSH

BACKGROUND: The patterns and processes linked to the host specificity of parasites represent one of the central themes in the study of host-parasite interactions. We investigated the evolution and determinants of host specificity in gill monogeneans of Cichlidogyrus and Scutogyrus species parasitizing African freshwater fish of Cichlidae. METHODS: We analyzed (1) the link between host specificity and parasite phylogeny, (2) potential morphometric correlates of host specificity (i.e. parasite body size and the morphometrics of the attachment apparatus), and (3) potential determinants of host specificity following the hypothesis of ecological specialization and the hypothesis of specialization on predictable resources (i.e. host body size and longevity were considered as measures of host predictability), and (4) the role of brooding behavior of cichlids in Cichlidogyrus and Scutogyrus diversification. RESULTS: No significant relationships were found between host specificity and phylogeny of Cichlidogyrus and Scutogyrus species. The mapping of host specificity onto the parasite phylogenetic tree revealed that an intermediate specialist parasitizing congeneric cichlid hosts represents the ancestral state for the Cichlidogyrus/Scutogyrus group. Only a weak relationship was found between the morphometry of the parasites' attachment apparatus and host specificity. Our study did not support the specialization on predictable resources or ecological specialization hypotheses. Nevertheless, host specificity was significantly related to fish phylogeny and form of parental care. CONCLUSIONS: Our results confirm that host specificity is not a derived condition for Cichlidogyrus/Scutogyrus parasites and may reflect other than historical constraints. Attachment apparatus morphometry reflects only partially (if at all) parasite adaptation to the host species, probably because of the morphological similarity of rapidly evolved cichlids (analyzed in our study). However, we showed that parental care behavior of cichlids may play an important role linked to host specificity of Cichlidogyrus/Scutogyrus parasites.

• MeSH
• biologická evoluce MeSH
• cichlidy parazitologie   MeSH
• fylogeneze MeSH
• hostitelská specificita * MeSH
• infekce červy třídy Trematoda parazitologie   veterinární   MeSH
• interakce hostitele a parazita * MeSH
• nemoci ryb parazitologie   MeSH
• ploštěnci genetika   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH