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Berlin Brandenburg

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  • 1
    Language: English
    In: Experimental and Applied Acarology, 2014, Vol.64(1), pp.109-119
    Description: The ranges of many tick species are changing due to climate change and human alteration of the landscape. Understanding tick responses to environmental conditions and how sampling method influences measurement of tick communities will improve our assessment of human disease risk. We compared tick sampling by three collection methods (dragging, CO 2 trapping and rodent surveys) in adjacent forested and grassland habitats in the lower Midwest, USA, and analyzed the relationship between tick abundance and microclimate conditions. The study areas were within the overlapping ranges of three tick species, which may provide conditions for pathogen exchange and spread into new vectors. Dermacentor variabilis (American dog tick) was found using all methods, Amblyomma americanum (lonestar tick) was found by dragging and CO 2 trapping and Ixodes scapularis (blacklegged deer tick) was found only on rodents. Proportion of each species differed significantly among sampling methods. More ticks were found in forests compared to open habitats. Further, more ticks were collected by dragging and from rodents in hotter, drier conditions. Our results demonstrate that multiple sampling methodologies better measure the tick community and that microclimate conditions strongly influence the abundance and activity of individual tick species.
    Keywords: Amblyomma americanum ; Dermacentor variabilis ; Ixodes scapularis ; Sampling methods ; Microclimate
    ISSN: 0168-8162
    E-ISSN: 1572-9702
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  • 2
    In: Molecular Ecology, May 2015, Vol.24(10), pp.2566-2579
    Description: High‐throughput sequencing is revealing that most macro‐organisms house diverse microbial communities. Of particular interest are disease vectors whose microbiome could potentially affect pathogen transmission and vector competence. We investigated bacterial community composition and diversity of the ticks ( = 68) and ( = 15) and blood of their shared rodent host, ( = 45) to quantify bacterial diversity and concordance. The 16S gene was amplified from genomic from field‐collected tick and rodent blood samples, and 454 pyrosequencing was used to elucidate their bacterial communities. After quality control, over 300 000 sequences were obtained and classified into 118 operational taxonomic units (s, clustered at 97% similarity). Analysis of rarefied communities revealed that the most abundant s were tick species‐specific endosymbionts, and and the commonly flea‐associated bacterium in rodent blood. An and additional endosymbiont were also present in samples. was found in both tick species but not in rodent blood, suggesting that it is not transmitted during feeding. was present in larvae and nymphs of both tick species, even those scored as unengorged. Relatively, few s (e.g. ,) were found in all sample types. Overall, bacterial communities from each sample type were significantly different and highly structured, independent of their dominant s. Our results point to complex microbial assemblages inhabiting ticks and host blood including infectious agents, tick‐specific endosymbionts and environmental bacteria that could potentially affect arthropod‐vectored disease dynamics.
    Keywords: Bartonella ; Blood ; Dermacentor ; Francisella ; Ixodes ; Microbiome ; Peromyscus ; Rickettsia
    ISSN: 0962-1083
    E-ISSN: 1365-294X
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  • 3
    Language: English
    In: Trends in Parasitology, May 2015, Vol.31(5), pp.212-221
    Description: Hosts are typically coinfected by multiple parasite species, resulting in potentially overwhelming levels of complexity. We argue that an individual host can be considered to be an ecosystem in that it is an environment containing a diversity of entities (e.g., parasitic organisms, commensal symbionts, host immune components) that interact with each other, potentially competing for space, energy, and resources, ultimately influencing the condition of the host. Tools and concepts from ecosystem ecology can be applied to better understand the dynamics and responses of within-individual host–parasite ecosystems. Examples from both wildlife and human systems demonstrate how this framework is useful in breaking down complex interactions into components that can be monitored, measured, and managed to inform the design of better disease-management strategies.
    Keywords: Biology ; Veterinary Medicine
    ISSN: 1471-4922
    E-ISSN: 1471-5007
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  • 4
    Language: English
    In: Parasitology Research, 2013, Vol.112(4), pp.1763-1770
    Description: Immune function is an important component of host fitness, and high investment in immunity should occur when the benefits outweigh the costs, such as when risk of parasitism is high. We sampled two rodent hosts, white-footed mice ( Peromyscus leucopus ), and prairie voles ( Microtus ochrogaster ), and their tick, flea, and mite ectoparasites. A bacterial killing assay was used to measure the host’s innate immune function. We hypothesized that classes of hosts (species, sexes, or age classes) with overall higher tick burdens would have a higher innate immune function as an evolutionary response to historically greater exposure. We hypothesized a weaker relationship between the fleas and mites and immune function because of high host specificity in fleas and the absence of known vector function in North American mites. Ectoparasites were significantly overdispersed on hosts. In accordance with our hypothesis, Peromyscus that had higher tick burdens also exhibited significantly higher bacterial killing ability compared to Microtus . There was no significant difference in total flea burden between rodent species and no relationship with bacterial killing ability. Microtus had higher burdens of mites in each order than Peromyscus , and female rodents had higher mite burdens than males. The benefits of maintaining high levels of innate immune factors appear to be greater than the energetic costs for Peromyscus compared to Microtus .
    Keywords: Zoology;
    ISSN: 0932-0113
    E-ISSN: 1432-1955
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  • 5
    Language: English
    In: Israel journal of ecology & evolution, 2010, Vol.56(3), pp.417-431
    Description: Microbial infections typically do not occur in isolation but co-occur within diverse communities of bacteria, fungi, protozoans, and viruses. Co-infections can lead to increased disease severity, lead to selection for increased virulence, and complicate disease diagnosis and treatment. Co-infections also occur in disease vectors, and represent one source of co-infections in hosts. We examined patterns of co-infections in ticks (Order Acari), which vector diverse human and wildlife pathogens, and asked whether the frequency of microbial co-infections deviated significantly from independent associations. Most published data were from Ixodes species and reported infection and co-infection frequencies of Borrelia burgdorferi and Anaplasma phagocytophilum. A total of 18 datasets representing 4978 adult ticks met our criteria for inclusion in the meta-analysis. Significant deviations from independent co-infection were detected in eight of the 18 populations. Five populations exhibited a significant excess of A. phagocytophilum/B. burgdorferi co-infections, including all populations of I. ricinus that deviated from independence. In contrast, both populations of I. persulcatus and one of two populations of I. scapularis exhibited a significant deficit of co-infection. The single population of I. pacificus examined had a significant excess of co-infection. Our meta-analyses indicate that tick-borne microbes are often distributed non-randomly, but the direction of deviation was not consistent, indicating that multiple mechanisms contribute to these patterns. Unfortunately, most published studies were not designed to describe patterns of co-infection, and provided insufficient data for our meta-analysis. Future studies should more explicitly measure and report co-infections in ticks, including co-infections by endosymbionts. ; p. 417-431.
    Keywords: Ixodes ; Data Collection ; Ticks ; Mixed Infection ; Borrelia Burgdorferi ; Anaplasma Phagocytophilum ; Endosymbionts ; Wildlife ; Pathogens ; Bacterial Communities ; Disease Severity ; Meta-Analysis ; Fungi ; Disease Diagnosis ; Adults ; Hosts ; Virulence ; Disease Vectors
    ISSN: 1565-9801
    E-ISSN: 22244662
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  • 6
    In: The ISME Journal, 2012, Vol.7(1), p.221
    Description: Bacterial community composition in blood-sucking arthropods can shift dramatically across time and space. We used 16S rRNA gene amplification and pyrosequencing to investigate the relative impact of vertebrate host-related, arthropod-related and environmental factors on bacterial community composition in fleas and ticks collected from rodents in southern Indiana (USA). Bacterial community composition was largely affected by arthropod identity, but not by the rodent host or environmental conditions. Specifically, the arthropod group (fleas vs ticks) determined the community composition of bacteria, where bacterial communities of ticks were less diverse and more dependent on arthropod traits--especially tick species and life stage--than bacterial communities of fleas. Our data suggest that both arthropod life histories and the presence of arthropod-specific endosymbionts may mask the effects of the vertebrate host and its environment.
    Keywords: Biology;
    ISSN: 1751-7362
    E-ISSN: 17517370
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  • 7
    Language: English
    In: Frontiers in Immunology, 01 February 2018, Vol.9
    Description: Parasitic helminths are extremely resilient in their ability to maintain chronic infection burdens despite (or maybe because of) their hosts’ immune response. Explaining how parasites maintain these lifelong infections, identifying the protective immune mechanisms that regulate helminth infection burdens, and designing prophylactics and therapeutics that combat helminth infection, while preserving host health requires a far better understanding of how the immune system functions in natural habitats than we have at present. It is, therefore, necessary to complement mechanistic laboratory-based studies with studies on wild populations and their natural parasite communities. Unfortunately, the relative paucity of immunological tools for non-model species has held these types of studies back. Thankfully, recent progress in high-throughput ‘omics platforms provide powerful and increasingly practical means for immunologists to move beyond traditional lab-based model organisms. Yet, assigning both metabolic and immune function to genes, transcripts, and proteins in novel species and assessing how they interact with other physiological and environmental factors requires identifying quantitative relationships between their expression and infection. Here, we used supervised machine learning to identify gene networks robustly associated with burdens of the gastrointestinal nematode Heligmosomoides polygyrus in its natural host, the wild wood mice Apodemus sylvaticus. Across 34 mice spanning two wild populations and across two different seasons, we found 17,639 transcripts that clustered in 131 weighted gene networks. These clusters robustly predicted H. polygyrus burden and included well-known effector and regulatory immune genes, but also revealed a number of genes associated with the maintenance of tissue homeostasis and hematopoiesis that have so far received little attention. We then tested the effect of experimentally reducing helminth burdens through drug treatment on those putatively protective immune factors. Despite the near elimination of H. polygyrus worms, the treatment had surprisingly little effect on gene expression. Taken together, these results suggest that hosts balance tissue homeostasis and protective immunity, resulting in relatively stable immune and, consequently, parasitological profiles. In the future, applying our approach to larger numbers of samples from additional populations will help further increase our ability to detect the immune pathways that determine chronic gastrointestinal helminth burdens in the wild.
    Keywords: Wild Immunology ; Apodemus Sylvaticus ; Transcriptome ; Machine Learning Applied to Immunology ; Heligmosomoides Polygyrus ; Anthelminthics ; Biology
    E-ISSN: 1664-3224
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  • 8
    Description: Background: Wild hosts are commonly co-infected with complex, genetically diverse, pathogen communities. Competition is expected between genetically or ecologically similar pathogen strains which may influence patterns of coexistence. However, there is little data on how specific strains of these diverse pathogen species interact within the host and how this impacts pathogen persistence in nature. Ticks are the most common disease vector in temperate regions with Borrelia burgdorferi, the causative agent of Lyme disease, being the most common vector-borne pathogen in North America. Borrelia burgdorferi is a pathogen of high public health concern and there is significant variation in infection phenotype between strains, which influences predictions of pathogen dynamics and spread. Methods: In a laboratory experiment, we investigated whether two closely-related strains of B. burgdorferi (sensu stricto) showed...
    Keywords: Ixodes Scapularis ; Peromyscus Leucopus ; Borrelia Burgdorferi ; Parasitology ; Ecology
    ISBN: 〈relatedIdentifier relatedIdentifierType="ISBN" relationType="IsPartOf"/〉
    ISSN: 1756-3305
    Source: DataCite
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  • 9
    Language: English
    In: Parasites & vectors, 06 February 2017, Vol.10(1), pp.64
    Description: Wild hosts are commonly co-infected with complex, genetically diverse, pathogen communities. Competition is expected between genetically or ecologically similar pathogen strains which may influence patterns of coexistence. However, there is little data on how specific strains of these diverse pathogen species interact within the host and how this impacts pathogen persistence in nature. Ticks are the most common disease vector in temperate regions with Borrelia burgdorferi, the causative agent of Lyme disease, being the most common vector-borne pathogen in North America. Borrelia burgdorferi is a pathogen of high public health concern and there is significant variation in infection phenotype between strains, which influences predictions of pathogen dynamics and spread. In a laboratory experiment, we investigated whether two closely-related strains of B. burgdorferi (sensu stricto) showed similar transmission phenotypes, how the transmission of these strains changed when a host was infected with one strain, re-infected with the same strain, or co-infected with two strains. Ixodes scapularis, the black-legged tick, nymphs were used to sequentially infect laboratory-bred Peromyscus leucopus, white-footed mice, with one strain only, homologous infection with the same stain, or heterologous infection with both strains. We used the results of this laboratory experiment to simulate long-term persistence and maintenance of each strain in a simple simulation model. Strain LG734 was more competitive than BL206, showing no difference in transmission between the heterologous infection groups and single-infection controls, while strain BL206 transmission was significantly reduced when strain LG734 infected first. The results of the model show that this asymmetry in competition could lead to extinction of strain BL206 unless there was a tick-to-host transmission advantage to this less competitive strain. This asymmetric competitive interaction suggests that strain identity and the biotic context of co-infection is important to predict strain dynamics and persistence.
    Keywords: Co-Infection ; Ixodes Scapularis ; Peromyscus Leucopus ; Strain Diversity ; Antibiosis ; Arachnid Vectors ; Genetic Fitness ; Borrelia Burgdorferi -- Physiology ; Ixodes -- Microbiology
    E-ISSN: 1756-3305
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  • 10
    Keywords: Microbiome ; Tick ; Blood ; Indiana ; Usa ; Dermacentor Variabilis ; Ixodes Scapularis ; Peromyscus Leucopus ; Bartonella ; Francisella ; Rickettsia
    Source: DataCite
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