Polyphenols as Potential Geroprotectors.

Significance: Currently, a large amount of evidence of beneficial effects of diets enriched with polyphenols on various aspects of health has been accumulated. These phytochemicals have a geroprotective potential slowing down the pathological processes associated with aging and ensuring longevity. In this study, a comprehensive analysis was conducted to determine the adherence of individual polyphenols to geroprotector criteria. Data from experimental models, clinical trials, and epidemiological studies were analyzed. Recent Advances: Sixty-two polyphenols have been described to increase the life span and improve biomarkers of aging in animal models. They act via evolutionarily conserved molecular mechanisms, including hormesis and maintenance of redox homeostasis, epigenetic regulation, response to cellular damage, metabolic control, and anti-inflammatory and senolytic activity. Epidemiological and clinical studies suggest that certain polyphenols have a potential for prevention and treatment of various diseases, including cancer, metabolic disorders, and cardiovascular conditions in humans. Critical Issues: Among the reviewed phytochemicals, chlorogenic acid, quercetin, epicatechin, genistein, resveratrol, and curcumin were identified as compounds with the highest geroprotective potential. However, there is a lack of unambiguous information on the effectiveness and safety of polyphenols for increasing health span, preventing and treating aging-associated diseases in humans. Future Directions: Further research is needed to fully understand the effects of polyphenols considering their long-term consumption, metabolic modification and bioavailability, complex interactions between different groups of polyphenols and with other phytochemicals, as well as their effects on individuals with different health status. Antioxid. Redox Signal. 40, 564-593.

Spatial variability in herbaceous plant phenology is mostly explained by variability in temperature but also by photoperiod and functional traits.

Whereas temporal variability of plant phenology in response to climate change has already been well studied, the spatial variability of phenology is not well understood. Given that phenological shifts may affect biotic interactions, there is a need to investigate how the variability in environmental factors relates to the spatial variability in herbaceous species' phenology by at the same time considering their functional traits to predict their general and species-specific responses to future climate change. In this project, we analysed phenology records of 148 herbaceous species, which were observed for a single year by the PhenObs network in 15 botanical gardens. For each species, we characterised the spatial variability in six different phenological stages across gardens. We used boosted regression trees to link these variabilities in phenology to the variability in environmental parameters (temperature, latitude and local habitat conditions) as well as species traits (seed mass, vegetative height, specific leaf area and temporal niche) hypothesised to be related to phenology variability. We found that spatial variability in the phenology of herbaceous species was mainly driven by the variability in temperature but also photoperiod was an important driving factor for some phenological stages. In addition, we found that early-flowering and less competitive species characterised by small specific leaf area and vegetative height were more variable in their phenology. Our findings contribute to the field of phenology by showing that besides temperature, photoperiod and functional traits are important to be included when spatial variability of herbaceous species is investigated.

Berberis vulgaris L. extract supplementation exerts regulatory effects on the lifespan and healthspan of Drosophila through its antioxidant activity depending on the sex.

Worldwide the aging population continues to increase, so the concept of healthy longevity medicine has become increasingly significant in modern society. Berberis vulgaris L. fruits serve as a functional food supplement with a high concentration of bioactive compounds, which offer numerous health-promoting benefits. The goal of this study was to investigate the geroprotective effect of Berberis vulgaris L. extract. Here we show that extract of Berberis vulgaris L. can, depending on concentrate, increases lifespan up to 6%, promote healthspan (stress resistance up to 35%, locomotor activity up to 25%, integrity of the intestinal barrier up to 12%, metabolic rate up to 5%) of Drosophila melanogaster (in vitro) and exhibits antioxidant (using red blood cell tests) and antiglycation activity (using glycation of bovine serum albumin) (in vitro). In addition to this, the extract does not exhibit cytotoxic properties in vitro, unlike the well-known polyphenolic compound quercetin. qRT-PCR has revealed the involvement of metabolic, heat shock response and lipid metabolism genes in the observed effects.

Antioxidant Properties and Geroprotective Potential of Wheat Bran Extracts with Increased Content of Anthocyanins.

In recent years, there has been a focus on breeding wheat with high anthocyanin levels in order to improve food quality and human health. The objective of this study was to examine the antioxidant and geroprotective properties of wheat bran extracts using both in vitro and in vivo research methods. Two wheat lines were used: one with uncolored pericarp (anthocyanin-free) and another with colored pericarp (anthocyanin-containing). These lines differed in a specific region of chromosome 2A containing the Pp3/TaMyc1 gene, which regulates anthocyanin production. High-performance liquid chromatography-mass spectrometry revealed the presence of cyanidin glucoside and cyanidin arabinoside in the anthocyanin-containing wheat bran extract (+AWBE), while no anthocyanins were found in the anthocyanin-free wheat bran extract (-AWBE). The +AWBE showed higher radical scavenging activity (DPPH and ABTS assays) and membrane protective activity (AAPH oxidative hemolysis model) compared to the -AWBE. Both extracts extended the lifespan of female Drosophila, indicating geroprotective properties. This study demonstrates that wheat bran extracts with high anthocyanin levels have antioxidant and geroprotective effects. However, other secondary metabolites in wheat bran can also contribute to its antioxidant and geroprotective potential.

Fracture of Epoxy Matrixes Modified with Thermo-Plastic Polymers and Winding Glass Fibers Reinforced Plastics on Their Base under Low-Velocity Impact Condition.

The work is aimed at studying the impact resistance of epoxy oligomer matrices (EO) modified with polysulfone (PSU) or polyethersulfone (PES) and glass fibers reinforced plastics (GFRP) based on them under low-velocity impact conditions. The concentration dependences of strength and fracture energy of modified matrices and GFRP were determined. It has been determined that the type of concentration curves of the fracture energy of GFRP depends on the concentration and type of the modifying polymer. It is shown that strength σ and fracture energy EM of thermoplastic-modified epoxy matrices change little in the concentration range from 0 to 15 wt.%. However, even with the introduction of 20 wt.% PSU into EO, the strength increases from 164 MPa to 200 MPa, and the fracture energy from 32 kJ/m2 to 39 kJ/m2. The effect of increasing the strength and fracture energy of modified matrices is retained in GFRP. The maximum increase in shear strength (from 72 MPa to 87 MPa) is observed for GFRP based on the EO + 15 wt.% PSU matrix. For GFRP based on EO + 20 wt.% PES, the shear strength is reduced to 69 MPa. The opposite effect is observed for the EO + 20 wt.% PES matrix, where the strength value decreases from 164 MPa to 75 MPa, and the energy decreases from 32 kJ/m2 to 10 kJ/m2. The reference value for the fracture energy of GFRP 615 is 741 kJ/m2. The maximum fracture energy for GFRP is based on EO + 20 wt.% PSU increases to 832 kJ/m2 for GFRP based on EO + 20 wt.% PES-up to 950 kJ/m2. The study of the morphology of the fracture surfaces of matrices and GFRP confirmed the dependence of impact characteristics on the microstructure of the modified matrices and the degree of involvement in the process of crack formation. The greatest effect is achieved for matrices with a phase structure "thermoplastic matrix-epoxy dispersion." Correlations between the fracture energy and strength of EO + PES matrices and GFRP have been established.

Relationship Between Patient-Centered Primary Care Provider Communication and Emergency Room Visits in the Medicaid Population in North Carolina, United States.

INTRODUCTION: Medicaid, a joint federal-state program, finances health care for eligible low-income individuals and families in the United States. Medicaid patients use disproportionately more emergency room (ER) services than other patients in the United States. Inadequate provider communication during primary care visits might be one reason for this well-documented phenomenon. The goal of the study was to examine how patient-centered provider communication related to ER use by Medicaid patients in North Carolina. METHODS: A 2015 state-wide cross-sectional telephone survey of NC adult Medicaid patients (n = 2652) was based on the CAHPS methodology. Predictors were 4 patient-centered provider communication characteristics assessed by patients. The outcome was the number of ER visits during 6 months prior to the survey. We used negative binomial regression to examine the relationship. RESULTS: Effective patient-centered provider communication index was associated with 19% fewer ER visits (P < .05). Provider's respect for patients had the biggest impact on the number of visits (37% fewer ER visits, P < .001). Easy to understand provider explanations were associated with 18% fewer ER visits (P < .05). Longer (>1 year) patient continuity with the current primary care provider was associated with 36% to 38% fewer ER visits (P < .001). CONCLUSIONS: Health care quality improvement should focus on training providers how to show respect, give easily understood explanations, and maintain good interpersonal relationships with patients. Relevant agencies should emphasize training and accreditation with a specific emphasis on communication of providers delivering care to Medicaid patients.

New Building Blocks for Self-Healing Polymers.

The healing efficiency in self-healing materials is bound by the ability to form blends between the prepolymer and curing agent. One of the problems in the development of self-healing polymers is the reduced affinity of the bismaleimide curing agent for the elastomeric furan-containing matrix. Even when stoichiometric amounts of both components are applied, incompatibility of components can significantly reduce the effectiveness of self-healing, and lead to undesirable side effects, such as crystallization of the curing agent, in the thickness and on the surface. This is exactly what we have seen in the development of linear and cross-linked PUs using BMI as a hardener. In this work, we present a new series of the di- and tetrafuranic isocyanate-related ureas-promising curing agents for the development of polyurethanes-like self-healing materials via the Diels-Alder reaction. The commonly used isocyanates (4,4'-Methylene diphenyl diisocyanate, MDI; 2,4-Tolylene diisocyanate, TDI; and Hexamethylene diisocyanate, HDI) and furfurylamine, difurfurylamine, and furfuryl alcohol (derived from biorenewables) as furanic compounds were utilized for synthesis. The remendable polyurethane for testing was synthesized from a maleimide-terminated prepolymer and one of the T-series urea. Self-healing properties were investigated by thermal analysis. Molecular mass was determined by gel permeation chromatography. The properties of the new polymer were compared with polyurethane from a furan-terminated analog. Visual tests showed that the obtained material has thermally induced self-healing abilities. Resulting polyurethane (PU) has a rather low fusing point and thus may be used as potential material for Fused Deposition Modeling (FDM) 3D printing.

Anti-Microbiota Vaccine Reduces Avian Malaria Infection Within Mosquito Vectors.

Animal and human pathogens that are transmitted by arthropods are a global concern, particularly those vectored by mosquitoes (e.g., Plasmodium spp. and dengue virus). Vector microbiota may hold the key to vector-borne pathogen control, as mounting evidence suggests that the contributions of the vector microbiota to vector physiology and pathogen life cycle are so relevant that vectorial capacity cannot be understood without considering microbial communities within the vectors. Anti-tick microbiota vaccines targeting commensal bacteria of the vector microbiota alter vector feeding and modulate the taxonomic and functional profiles of vector microbiome, but their impact on vector-borne pathogen development within the vector has not been tested. In this study, we tested whether anti-microbiota vaccination in birds targeting Enterobacteriaceae within mosquito midguts modulates the mosquito microbiota and disrupt Plasmodium relictum development in its natural vector Culex quinquefasciatus. Domestic canaries (Serinus canaria domestica) were experimentally infected with P. relictum and/or immunized with live vaccines containing different strains of Escherichia coli. Immunization of birds induced E. coli-specific antibodies. The midgut microbial communities of mosquitoes fed on Plasmodium-infected and/or E. coli-immunized birds were different from those of mosquitoes fed on control birds. Notably, mosquito midgut microbiota modulation was associated with a significant decrease in the occurrence of P. relictum oocysts and sporozoites in the midguts and salivary glands of C. quinquefasciatus, respectively. A significant reduction in the number of oocysts was also observed. These findings suggest that anti-microbiota vaccines can be used as a novel tool to control malaria transmission and potentially other vector-borne pathogens.

A comparative analysis of the dynamics of Plasmodium relictum (GRW4) development in the blood during single and co-infections.

Although co-infections and interactions of parasites are a very common phenomenon in the wild, information received from studies on avian Plasmodium spp. is scarce and fragmented due to its complex nature. Different interactions of parasites and domination of one parasite may have a detrimental effect on transmission success of another pathogen. Untangling these interactions and competitive behavior of malarial parasites may help understanding why some haemosporidian parasites are dominant in certain host species, while others are observed only occasionally. We investigated the development of Plasmodium relictum (genetic lineage GRW4) during single and co-infection with a closely related lineage SGS1, with the aim to determine whether co-infections affect parasite development and condition of experimentally infected Eurasian siskins (Spinus spinus). For the experimental study of these two closely related lineages, a new qPCR protocol was designed to accurately quantify the parasitemia, i.e. the amount of infected red blood cells, during the blood stages of each of the lineages. Our results show that during co-infection, GRW4 parasitemia was transient and disappeared from peripheral blood during acute increases of SGS1. Health parameters of infected birds did not differ between the GRW4 single infected group and the co-infection group. GRW4 induced infection was outcompeted and suppressed by the presence of the lineage SGS1, which is broadly transmitted in Northern Europe. This suggests that double infections and dominating lineages in the area may influence the transmission success of some avian Plasmodium parasites.

The Impact of Temperature on the Sporogonic Development of the Tropical Avian Malaria Parasite Plasmodium relictum (Genetic Lineage pGRW4) in Culex pipiens Form molestus Mosquitoes.

The avian malaria parasite Plasmodium relictum (genetic lineage pGRW4) is known to cause severe pathology in nonadapted vertebrate hosts. This parasite is prevalent in some bird species in Northern Europe, however the records obtained are only from adult long-distance migrant birds after their return from the wintering grounds. A recent experimental study showed that this parasite completes sporogonic development in the local European vector Culex pipiens at a controlled mean temperature of 19 °C. Thereby, temperature limits for the transmission of this parasite in Northern Europe remain unknown. In this study, we took a step further and tested the impact of different temperature conditions, including some extreme fluctuations between 23 °C down to 7 °C, on the sporogonic development of P. relictum (pGRW4) in the vector Culex pipiens form molestus. Mosquitoes were exposed to infection and kept under different air-temperature conditions: (i) constant warm temperature, (ii) natural outdoor temperatures and (iii) temporary exposure to low temperatures. Plasmodium relictum (pGRW4) completed sporogony in mosquitoes of all experimental groups, however different patterns of the sporogonic development depending on temperature conditions were observed. Based on these results, we conclude that the cool air temperature of Northern Europe in summer is not a limiting factor in successful development of the parasite. However, delayed sporogony caused by low summer temperatures may have a detrimental impact on the active transmission of this parasite in Northern Europe.

Thermally Remendable Polyurethane Network Cross-Linked via Reversible Diels-Alder Reaction.

We prepared a series of thermally remendable and recyclable polyurethanes crosslinked via reversible furan-maleimide Diels-Alder reaction based on TDI end-caped branched Voranol 3138 terminated with difurfurylamine and 4,4'-bis(maleimido)diphenylmethane (BMI). We showed that Young modulus strongly depends on BMI content (from 8 to 250 MPa) that allows us to obtain materials of different elasticity as simple as varying BMI content. The ability of DA and retro-DA reactions between furan and maleimide to reversibly bind material components was investigated by NMR spectroscopy, differential scanning calorimetry, and recycle testing. All polymers obtained demonstrated high strengths and could be recovering without significant loss in mechanical properties for at least five reprocessing cycles.

Experimental study of newly described avian malaria parasite Plasmodium (Novyella) collidatum n. sp., genetic lineage pFANTAIL01 obtained from South Asian migrant bird.

BACKGROUND: Avian malaria parasites are microorganisms parasitizing erythrocytes and various tissues of the birds; they are common and distributed worldwide. These parasites are known to infect birds of different taxa and be the cause of the deaths of birds in the wild and in captivity. The species of parasites with the ability to colonize new territories and infect local non-migratory birds are of particular interest. This scenario is likely in temperate zones of Europe, because of climate change and its contribution in spreading vectors of southern origin, which can be involved in the transmission of malaria parasites. In the present study, a tropical Plasmodium parasite from a naturally infected long-distance migrant bird was isolated and tested for its ability to develop in common species of mosquitoes and European short-distance migrant birds. METHODS: Plasmodium sp. (pFANTAIL01) was isolated on the Curonian spit of the Baltic sea coast from the naturally infected Common rosefinch, Carpodacus erythrinus in June 2019. The parasite was described based on the morphological features of its blood stages, the partial mitochondrial cytochrome b gene and development after experimental infection of birds and mosquitoes. The parasite was inoculated into Eurasian siskins, Carduelis spinus. Parasitaemia, haematocrit and weight of birds were monitored. At the end of the survey, internal organs were collected to study exoerythrocytic stages of this parasite. Experimental infection of mosquitoes Culex pipiens form molestus and Culex quinquefasciatus was applied to study sporogonic development of the parasite. RESULTS: Based on morphological features, the parasite was described as a new species, Plasmodium collidatum n. sp., and attributed to subgenus Novyella. It was revealed that the obtained pFANTAIL01 lineage is a generalist parasite infecting a wide range of avian hosts and most likely is transmitted in South and Southeast (SE) Asia and Oceania. In Europe, this strain was recorded only in adult migratory birds wintering in South Asia. This parasite developed high parasitaemia in experimentally infected siskins and caused 25 % mortality. Exoerythrocytic stages of pFANTAIL01 were found in the lungs, liver, spleen and kidney of the deceased birds. Sporogonic development did not occur in Cx. pipiens form molestus and Cx. quinquefasciatus mosquitoes. CONCLUSIONS: Plasmodium collidatum is a highly virulent for Eurasian siskin and completes its development in these birds, which can be considered as a potential vertebrate host if the transmission of the infection starts occurring in Europe and temperate zones.

Culicoides biting midges involved in transmission of haemoproteids.

BACKGROUND: Culicoides biting midges (Diptera, Ceratopogonidae) are known vectors of avian Haemoproteus parasites. These parasites cause diseases, pathology and even mortality in birds. The diversity of biting midges in Europe is great, but only four Culicoides species are known to be vectors of avian Haemoproteus parasites. In general, our knowledge about the role of the particular Culicoides species in the transmission of Haemoproteus parasites remains insufficient. Information gaps hinder a better understanding of parasite biology and the epizootiology of parasite-caused diseases. The aim of this study was to determine new Culicoides species involved in the transmission of Haemoproteus parasites. METHODS: Biting midges were collected using a UV trap as well as sticky traps installed in bird nest boxes. Individual parous females were diagnosed for the presence of haemoproteids using both PCR-based and microscopic methods. RESULTS: We collected and dissected 232 parous Culicoides females from 9 species using a UV trap and 293 females from 11 species from bird nest boxes. Culicoides obsoletus was the dominant species collected using a UV trap, and Culicoides kibunensis dominated among midges collected in nest boxes. PCR-based screening showed that 5.2% of parous biting midges collected using a UV trap and 4.4% of midges collected from nest boxes were infected with avian haemosporidian parasites. Haemoproteid DNA was detected in C. kibunensis, Culicoides pictipennis, Culicoides punctatus, Culicoides segnis and Culicoides impunctatus females. The sporozoites of Haemoproteus minutus (genetic lineages hTURDUS2 and hTUPHI01) were detected in the salivary glands of two C. kibunensis females using microscopy, and this finding was confirmed by PCR. CONCLUSIONS: Culicoides kibunensis was detected as a new natural vector of Haemoproteus minutus (hTURDUS2 and hTUPHI01). Haemoproteid DNA was detected in females from five Culicoides species. This study contributes to the epizootiology of avian Haemoproteus infections by specifying Culicoides species as vectors and species that are likely to be responsible for the transmission of haemoproteids in Europe.

Dynamics of blood stage and sporozoite-induced malarial infections in experimentally infected passerines.

Complex experimental studies of vertebrate host, vector, and parasite interactions are essential in understanding virulence, but are difficult or impossible to conduct if vector species are unknown. Subinoculation of erythrocytic meronts of avian malarial parasites into susceptible hosts can avoid this problem, but this approach omits early exoerythrocytic stages, e.g. cryptozoites and metacryptozoites, that normally develop from sporozoites. A fundamental question that has remained unanswered is whether blood stage and sporozoite-induced malarial infections lead to differences in the dynamics of parasitemia in acute infections, patterns of parasite development, and host mortality. Here we demonstrate in a Carduelis spinus - Plasmodium relictum (genetic lineage pSGS1) system that experimental infections using inoculation of infected blood and using mosquito bite show similar peaks of parasitemias, but some measures of parasite development in the vertebrate host differ. Infected birds from all groups show decreased activity during the peak of parasitemia. There is no doubt that experimental infections using vectors provide the most precise information about the development of a parasite and its virulence in the host, but experimental infections using blood stages demonstrate similar parasitemias and effects on the host. These results are important for further experimental research of malarial parasites, especially studying avian Plasmodium parasites with unknown vectors.

Terpenoids as Potential Geroprotectors.

Terpenes and terpenoids are the largest groups of plant secondary metabolites. However, unlike polyphenols, they are rarely associated with geroprotective properties. Here we evaluated the conformity of the biological effects of terpenoids with the criteria of geroprotectors, including primary criteria (lifespan-extending effects in model organisms, improvement of aging biomarkers, low toxicity, minimal adverse effects, improvement of the quality of life) and secondary criteria (evolutionarily conserved mechanisms of action, reproducibility of the effects on different models, prevention of age-associated diseases, increasing of stress-resistance). The number of substances that demonstrate the greatest compliance with both primary and secondary criteria of geroprotectors were found among different classes of terpenoids. Thus, terpenoids are an underestimated source of potential geroprotectors that can effectively influence the mechanisms of aging and age-related diseases.

Complete sporogony of the blood parasite Haemoproteus nucleocondensus in common biting midges: why is its transmission interrupted in Europe?

Haemoproteus species (Haemoproteidae) are widespread blood parasites and are transmitted by Culicoides biting midges and Hippoboscidae louse flies. Although these pathogens may cause morbidity or mortality, the vectors and patterns of transmission remain unknown for the great majority of avian haemoproteids. Haemoproteus nucleocondensus has been frequently reported in Europe in great reed warblers Acrocephalus arundinaceus after their arrival from African wintering grounds, but this infection has not been found in juveniles at the breeding sites. The factors that prevent its transmission remain unclear. This study was designed to test whether the sporogony of H. nucleocondensus (lineage hGRW8) can be completed in Culicoides impunctatus, one of the most abundant European biting midge species. Wild-caught females were infected with H. nucleocondensus from great reed warblers. Microscopic examination and PCR-based methods were used to detect sporogonic stages and to confirm species identity. This study showed that H. nucleocondensus completes sporogony in C. impunctatus, suggesting that there are no obstacles to its transmission from the point of view of vector availability and average temperature in Northern Europe. We discuss other ecological factors which should be considered to explain why the transmission of H. nucleocondensus and some other Southern origin haemosporidians are interrupted in North Europe.

The Relationship between Patient-Centered Medical Home Characteristics and Patient Dissatisfaction at a Federally Qualified Health Center.

This cross-sectional study examined the relationship between patients' assessment of patient-centered medical home (PCMH) characteristics and patient experiences at a federally qualified health center. The survey was based on the Consumer Assessment of Health care Providers and Systems (CAHPS) instrument. Patient-centered medical home characteristics include access to care and coordination, provider communication, office staff helpfulness, and discrimination. Outcomes were related to patient experiences reflecting their dissatisfaction and lack of trust. Our sample (N = 257) was 76% female, 39% older than 50, 40% with college education, and 84% African American. We performed multiple logistic regression to examine the association between PCMH characteristics and patient dissatisfaction, adjusting for demographics. Approximately 26% of the participants reported dissatisfaction with at least one outcome. Effective provider communication was the primary contributor to decreased odds of patient dissatisfaction and lack of trust. The study highlights the prominence of provider communication for patients using safety-net providers.

The experimental study on susceptibility of common European songbirds to Plasmodium elongatum (lineage pGRW6), a widespread avian malaria parasite.

BACKGROUND: Plasmodium elongatum (cytochrome b lineage pGRW6) is a widespread avian malaria parasite, often causing severe disease in non-adapted hosts. This parasite lineage is of global distribution however, its virulence remains insufficiently understood, particularly in wild birds. Surprisingly, this infection has never been reported in Common starlings Sturnus vulgaris and Common crossbills Loxia curvirostra, common European songbirds which were extensively sampled across Europe. A hypothesis was proposed that these birds might be resistant to the pGRW6 infection. The aim of this study was to test this hypothesis. METHODS: Lineage pGRW6 was isolated from a naturally infected Eurasian reed warbler, multiplied in vivo and inoculated in Common starlings and Common crossbills. Experimental and control groups (8 birds in each) were maintained in controlled conditions and examined microscopically every 4 days. Haematocrit value and body mass were monitored in parallel. At the end of the experiment (44 days post exposure), samples of internal organs were collected and examined using histological methods for possible presence of phanerozoites. RESULTS: All control birds remained uninfected. Experimental starlings were resistant. All exposed crossbills were susceptible and survived until the end of this study. Prepatent period was 12-16 days post exposure. Light parasitaemia (< 0.7%) developed in all birds, and only few phanerozoites were seen in bone marrow cells of 5 of 8 experimentally infected crossbills. Significant changes were reported only in haematocrit value but not body mass in the exposed crossbills compared to controls. CONCLUSION: Plasmodium elongatum (pGRW6) is of low virulence in Common crossbills and is unable to develop in Common starlings, indicating innate resistance of the later bird species. Low virulence in Common crossbills is likely due to the inability or low ability of this parasite lineage to develop phanerozoites resulting in light (if at all) damage of stem bone marrow cells. This study suggests that susceptibility of different bird species to the lineage pGRW6 is markedly variable. The global distribution of this parasite might be due to low virulence in wild adapted avian hosts, which survive this infection and serve as reservoirs host for non-adapted birds in whom this infection is often lethal.