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Gvozdyak, R. I. "«Pathogen-1» Experiment Aggression of pathogenic bacteria in microgravity." Kosmìčna nauka ì tehnologìâ 6, no. 4 (July 30, 2000): 111. http://dx.doi.org/10.15407/knit2000.04.119.
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Conceição, Cinara Souza da, Barbara Victor Souza, Jessica Manya Bittencourt Dias Vieira, and Janaína dos Santos Nascimento. "Pathogen killing pathogen: antimicrobial substance from Acinetobacter active against foodborne pathogens." Journal of Infection in Developing Countries 12, no. 05 (May 31, 2018): 297–304. http://dx.doi.org/10.3855/jidc.9894.
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Introduction: Antimicrobial substances (AMS) produced by bacteria may reduce or prevent the growth of pathogenic and spoilage microorganisms in food. In this study, 16 isolates of Acinetobacter baumannii/calcoaceticus (ABC) complex, previously obtained from reconstituted infant milk formula (IMF) samples and the preparation and distribution utensils from the nursery of a public hospital, were used to screen for AMS production.
Methodology: Antimicrobial substance production and spectrum of activity assays were performed by agar-spot assay. Optimization of growth conditions for AMS production was also evaluated.
Results: Three (17.6%) isolates, namely JE3, JE4, and JE6, produced AMS against the principal indicator strain Salmonella enterica subsp. enterica serotype Typhi ATCC 19214. JE6 was also able to inhibit strains of Klebsiella pneumoniae, Proteus vulgaris, and Bacillus cereus, a Gram-positive bacteria. Remarkably, JE6 was able to inhibit all the tested resistant and multidrug-resistant (MDR) strains of the ABC complex and Shigella dysenteriae associated with IMF and utensils, indicating a potentially valuable application. AMS produced by JE6 does not appear to be affected by proteolytic enzymes and the producer strain showed specific immunity to its own AMS.
Conclusion: This study highlights AMS produced by Acinetobacter with applications against MDR spoilage and foodborne pathogens - some of them, infectious disease causing agents - which, to our knowledge, has not been previously described.
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Sánchez-Vallet, Andrea, Simone Fouché, Isabelle Fudal, Fanny E. Hartmann, Jessica L. Soyer, Aurélien Tellier, and Daniel Croll. "The Genome Biology of Effector Gene Evolution in Filamentous Plant Pathogens." Annual Review of Phytopathology 56, no. 1 (August 25, 2018): 21–40. http://dx.doi.org/10.1146/annurev-phyto-080516-035303.
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Filamentous pathogens, including fungi and oomycetes, pose major threats to global food security. Crop pathogens cause damage by secreting effectors that manipulate the host to the pathogen's advantage. Genes encoding such effectors are among the most rapidly evolving genes in pathogen genomes. Here, we review how the major characteristics of the emergence, function, and regulation of effector genes are tightly linked to the genomic compartments where these genes are located in pathogen genomes. The presence of repetitive elements in these compartments is associated with elevated rates of point mutations and sequence rearrangements with a major impact on effector diversification. The expression of many effectors converges on an epigenetic control mediated by the presence of repetitive elements. Population genomics analyses showed that rapidly evolving pathogens show high rates of turnover at effector loci and display a mosaic in effector presence-absence polymorphism among strains. We conclude that effective pathogen containment strategies require a thorough understanding of the effector genome biology and the pathogen's potential for rapid adaptation.
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Cunze, Sarah, Judith Kochmann, Lisa K. Koch, Korbinian J. Q. Hasselmann, and Sven Klimpel. "Leishmaniasis in Eurasia and Africa: geographical distribution of vector species and pathogens." Royal Society Open Science 6, no. 5 (May 2019): 190334. http://dx.doi.org/10.1098/rsos.190334.
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Leishmaniasis is a vector-borne disease with a broad global occurrence and an increasing number of recorded cases; however, it is still one of the world's most neglected diseases. We here provide climatic suitability maps generated by means of an ecological niche modelling approach for 32 Phlebotomus vector species with proven or suspected vector competence for five Leishmania pathogens occurring in Eurasia and Africa. A GIS-based spatial overlay analysis was then used to compare the distributional patterns of vectors and pathogens to help evaluate the vector species–pathogen relationship currently found in the literature. Based on this single factor of vector incrimination, that is, co-occurrence of both vector and pathogen, most of the pathogens occurred with at least one of the associated vector species. In the case of L. donovani , only a not yet confirmed vector species, P. rodhaini, could explain the occurrence of the pathogen in regions of Africa. Phlebotomus alexandri and P. longiductus on the other hand, proven vector species of L. donovani, do not seem to qualify as vectors for the pathogen. Their distribution is restricted to northern latitudes and does not match the pathogen's distribution, which lies in southern latitudes. Other more locally confined mismatches were discussed for each pathogen species. The comparative geographical GIS-overlay of vector species and pathogens functions as a first indication that testing and re-evaluation of some pathogen–vector relationships might be worthwhile to improve risk assessments of leishmaniasis.
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Mazarei, Mitra, Irina Teplova, M. Hajimorad, and C. Stewart. "Pathogen Phytosensing: Plants to Report Plant Pathogens." Sensors 8, no. 4 (April 14, 2008): 2628–41. http://dx.doi.org/10.3390/s8042628.
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Lepper, Simone, and Sylvia Münter. "Spotlight on pathogens: ‘Imaging Host-Pathogen Interactions’." Cellular Microbiology 11, no. 6 (June 2009): 855–62. http://dx.doi.org/10.1111/j.1462-5822.2009.01321.x.
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Fonville, Judith M. "Expected Effect of Deleterious Mutations on Within-Host Adaptation of Pathogens." Journal of Virology 89, no. 18 (June 24, 2015): 9242–51. http://dx.doi.org/10.1128/jvi.00832-15.
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ABSTRACTAdaptation is a common theme in both pathogen emergence, for example, in zoonotic cross-species transmission, and pathogen control, where adaptation might limit the effect of the immune response and antiviral treatment. When such evolution requires deleterious intermediate mutations, fitness ridges and valleys arise in the pathogen's fitness landscape. The effect of deleterious intermediate mutations on within-host pathogen adaptation is examined with deterministic calculations, appropriate for pathogens replicating in large populations with high error rates. The effect of deleterious intermediate mutations on pathogen adaptation is smaller than their name might suggest: when two mutations are required and each individual single mutation is fully deleterious, the pathogen can jump across the fitness valley by obtaining two mutations at once, leading to a proportion of adapted mutants that is 20-fold lower than that in the situation where the fitness of all mutants is neutral. The negative effects of deleterious intermediates are typically substantially smaller and outweighed by the fitness advantages of the adapted mutant. Moreover, requiring a specific mutation order has a substantially smaller effect on pathogen adaptation than the effect of all intermediates being deleterious. These results can be rationalized when the number of routes of mutation available to the pathogen is calculated, providing a simple approach to estimate the effect of deleterious mutations. The calculations discussed here are applicable when the effect of deleterious mutations on the within-host adaptation of pathogens is assessed, for example, in the context of zoonotic emergence, antigenic escape, and drug resistance.IMPORTANCEAdaptation is critical for pathogens after zoonotic transmission into a new host species or to achieve antigenic immune escape and drug resistance. Using a deterministic approach, the effects of deleterious intermediate mutations on pathogen adaptation were calculated while avoiding commonly made simplifications that do not apply to large pathogen populations replicating with high mutation rates. Perhaps unexpectedly, pathogen adaptation does not halt when the intermediate mutations are fully deleterious. The negative effects of deleterious mutations are substantially outweighed by the fitness gains of adaptation. To gain an understanding of the effect of deleterious mutations on pathogen adaptation, a simple approach that counts the number of routes available to the pathogen with and without deleterious intermediate mutations is introduced. This methodology enables a straightforward calculation of the proportion of the pathogen population that will cross a fitness valley or traverse a fitness ridge, without reverting to more complicated mathematical models.
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Singer, Merrill. "Pathogen-pathogen interaction." Virulence 1, no. 1 (January 2010): 10–18. http://dx.doi.org/10.4161/viru.1.1.9933.
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Chen, Huanhuan, Guangshuo Zhang, Guiling Ding, Jiaxing Huang, Hong Zhang, Mayra C. Vidal, Richard T. Corlett, Cong Liu, and Jiandong An. "Interspecific Host Variation and Biotic Interactions Drive Pathogen Community Assembly in Chinese Bumblebees." Insects 14, no. 11 (November 17, 2023): 887. http://dx.doi.org/10.3390/insects14110887.
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Bumblebees have been considered one of the most important pollinators on the planet. However, recent reports of bumblebee decline have raised concern about a significant threat to ecosystem stability. Infectious diseases caused by multiple pathogen infections have been increasingly recognized as an important mechanism behind this decline worldwide. Understanding the determining factors that influence the assembly and composition of pathogen communities among bumblebees can provide important implications for predicting infectious disease dynamics and making effective conservation policies. Here, we study the relative importance of biotic interactions versus interspecific host resistance in shaping the pathogen community composition of bumblebees in China. We first conducted a comprehensive survey of 13 pathogens from 22 bumblebee species across China. We then applied joint species distribution modeling to assess the determinants of pathogen community composition and examine the presence and strength of pathogen–pathogen associations. We found that host species explained most of the variations in pathogen occurrences and composition, suggesting that host specificity was the most important variable in predicting pathogen occurrences and community composition in bumblebees. Moreover, we detected both positive and negative associations among pathogens, indicating the role of competition and facilitation among pathogens in determining pathogen community assembly. Our research demonstrates the power of a pluralistic framework integrating field survey of bumblebee pathogens with community ecology frameworks to understand the underlying mechanisms of pathogen community assembly.
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Lin, Borong, Xue Qing, Jinling Liao, and Kan Zhuo. "Role of Protein Glycosylation in Host-Pathogen Interaction." Cells 9, no. 4 (April 20, 2020): 1022. http://dx.doi.org/10.3390/cells9041022.
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Host-pathogen interactions are fundamental to our understanding of infectious diseases. Protein glycosylation is one kind of common post-translational modification, forming glycoproteins and modulating numerous important biological processes. It also occurs in host-pathogen interaction, affecting host resistance or pathogen virulence often because glycans regulate protein conformation, activity, and stability, etc. This review summarizes various roles of different glycoproteins during the interaction, which include: host glycoproteins prevent pathogens as barriers; pathogen glycoproteins promote pathogens to attack host proteins as weapons; pathogens glycosylate proteins of the host to enhance virulence; and hosts sense pathogen glycoproteins to induce resistance. In addition, this review also intends to summarize the roles of lectin (a class of protein entangled with glycoprotein) in host-pathogen interactions, including bacterial adhesins, viral lectins or host lectins. Although these studies show the importance of protein glycosylation in host-pathogen interaction, much remains to be discovered about the interaction mechanism.
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Wu, J., S. C. Long, D. Das, and S. M. Dorner. "Are microbial indicators and pathogens correlated? A statistical analysis of 40 years of research." Journal of Water and Health 9, no. 2 (April 25, 2011): 265–78. http://dx.doi.org/10.2166/wh.2011.117.
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Indicator organisms are used to assess public health risk in recreational waters, to highlight periods of challenge to drinking water treatment plants, and to determine the effectiveness of treatment and the quality of distributed water. However, many have questioned their efficacy for indicating pathogen risk. Five hundred and forty cases representing independent indicator–pathogen correlations were obtained from the literature for the period 1970–2009. The data were analyzed to assess factors affecting correlations using a logistic regression model considering indicator classes, pathogen classes, water types, pathogen sources, sample size, the number of samples with pathogens, the detection method, year of publication and statistical methods. Although no single indicator was identified as the most correlated with pathogens, coliphages, F-specific coliphages, Clostridium perfringens, fecal streptococci and total coliforms were more likely than other indicators to be correlated with pathogens. The most important factors in determining correlations between indicator–pathogen pairs were the sample size and the number of samples positive for pathogens. Pathogen sources, detection methods and other variables have little influence on correlations between indicators and pathogens. Results suggest that much of the controversy with regards to indicator and pathogen correlations is the result of studies with insufficient data for assessing correlations.
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Delavaux, Camille S., Josh L. Schemanski, Geoffrey L. House, Alice G. Tipton, Benjamin Sikes, and James D. Bever. "Root pathogen diversity and composition varies with climate in undisturbed grasslands, but less so in anthropogenically disturbed grasslands." ISME Journal 15, no. 1 (September 21, 2020): 304–17. http://dx.doi.org/10.1038/s41396-020-00783-z.
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AbstractSoil-borne pathogens structure plant communities, shaping their diversity, and through these effects may mediate plant responses to climate change and disturbance. Little is known, however, about the environmental determinants of plant pathogen communities. Therefore, we explored the impact of climate gradients and anthropogenic disturbance on root-associated pathogens in grasslands. We examined the community structure of two pathogenic groups—fungal pathogens and oomycetes—in undisturbed and anthropogenically disturbed grasslands across a natural precipitation and temperature gradient in the Midwestern USA. In undisturbed grasslands, precipitation and temperature gradients were important predictors of pathogen community richness and composition. Oomycete richness increased with precipitation, while fungal pathogen richness depended on an interaction of precipitation and temperature, with precipitation increasing richness most with higher temperatures. Disturbance altered plant pathogen composition and precipitation and temperature had a reduced effect on pathogen richness and composition in disturbed grasslands. Because pathogens can mediate plant community diversity and structure, the sensitivity of pathogens to disturbance and climate suggests that degradation of the pathogen community may mediate loss, or limit restoration of, native plant diversity in disturbed grasslands, and may modify plant community response to climate change.
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Li, Mei, Thomas Pommier, Yue Yin, Jianing Wang, Shaohua Gu, Alexandre Jousset, Joost Keuskamp, et al. "Indirect reduction of Ralstonia solanacearum via pathogen helper inhibition." ISME Journal 16, no. 3 (October 20, 2021): 868–75. http://dx.doi.org/10.1038/s41396-021-01126-2.
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AbstractThe rhizosphere microbiome forms a first line of defense against soilborne pathogens. To date, most microbiome enhancement strategies have relied on bioaugmentation with antagonistic microorganisms that directly inhibit pathogens. Previous studies have shown that some root-associated bacteria are able to facilitate pathogen growth. We therefore hypothesized that inhibiting such pathogen helpers may help reduce pathogen densities. We examined tripartite interactions between a model pathogen, Ralstonia solanacearum, two model helper strains and a collection of 46 bacterial isolates recovered from the tomato rhizosphere. This system allowed us to examine the importance of direct (effects of rhizobacteria on pathogen growth) and indirect (effects of rhizobacteria on helper growth) pathways affecting pathogen growth. We found that the interaction between rhizosphere isolates and the helper strains was the major determinant of pathogen suppression both in vitro and in vivo. We therefore propose that controlling microbiome composition to prevent the growth of pathogen helpers may become part of sustainable strategies for pathogen control.
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McLeod, David V., and Troy Day. "Pathogen evolution under host avoidance plasticity." Proceedings of the Royal Society B: Biological Sciences 282, no. 1814 (September 7, 2015): 20151656. http://dx.doi.org/10.1098/rspb.2015.1656.
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Host resistance consists of defences that limit pathogen burden, and can be classified as either adaptations targeting recovery from infection or those focused upon infection avoidance. Conventional theory treats avoidance as a fixed strategy which does not vary from one interaction to the next. However, there is increasing empirical evidence that many avoidance strategies are triggered by external stimuli, and thus should be treated as phenotypically plastic responses. Here, we consider the implications of avoidance plasticity for host–pathogen coevolution. We uncover a number of predictions challenging current theory. First, in the absence of pathogen trade-offs, plasticity can restrain pathogen evolution; moreover, the pathogen exploits conditions in which the host would otherwise invest less in resistance, causing resistance escalation. Second, when transmission trades off with pathogen-induced mortality, plasticity encourages avirulence, resulting in a superior fitness outcome for both host and pathogen. Third, plasticity ensures the sterilizing effect of pathogens has consequences for pathogen evolution. When pathogens castrate hosts, selection forces them to minimize mortality virulence; moreover, when transmission trades off with sterility alone, resistance plasticity is sufficient to prevent pathogens from evolving to fully castrate.
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Basri, Hasan. "Texture Feature Extraction of Pathogen Microscopic Image Using Discrete Wavelet Transform." Jurnal Riset Informatika 5, no. 1 (December 14, 2022): 549–54. http://dx.doi.org/10.34288/jri.v5i1.488.
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This study used a case study of Jabon leaves, and the pathogen is one of the causes of disease that attack the leaves of jabon, one of the leaf spots and leaf blight. Discovery of leaf spot disease in different pathogens and leaf blight. The pathogen was obtained from the leaf spot of Curvularia sp. 1 and Pestalotia sp., while the pathogen came from Curvularia sp. 2 and Botrytis sp. Identify the pathogen as soon as possible to minimize its effects. Improper handling can lead to increased virulence and resistance to the pathogen. Improper handling also can cause a disease outbreak (disease epidemic) in a region. This study is the first step in identifying the pathogens responsible for Jabon leaf disease. In this study, the Application of Koch's Postulates method to achieve the purification of pathogens and retrieve the microscopic pathogen image as the data acquisition stage. Furthermore, use of the segmentation stage to separate the object pathogen from the background, and one of the methods used is Otsu Thresholding. The extraction process of pathogen microscopic image using Discrete Wavelet Transform (DWT), DWT extraction results can be obtained using energy and entropy information.
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MURAKAMI, TAKU. "Filter-Based Pathogen Enrichment Technology for Detection of Multiple Viable Foodborne Pathogens in 1 Day." Journal of Food Protection 75, no. 9 (September 1, 2012): 1603–10. http://dx.doi.org/10.4315/0362-028x.jfp-12-039.
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Conventional foodborne pathogen assays currently used in the food industry often require long culture enrichments to increase pathogen levels so they can be detected. Even using sensitive real-time PCR assays, culture enrichment at least overnight is necessary especially for detection of pathogens with slow growth rates such as Listeria monocytogenes. To eliminate this cumbersome enrichment step and detect minute amounts of pathogens within 1 day, filter-based pathogen enrichment technology was developed utilizing a unique combination of glass fiber depth filter and porous filter aid materials to efficiently separate pathogens from food homogenates and avoid filter clogging by food particles. After pathogen immobilization in depth filters, only viable pathogens were selectively collected in a small volume of growth medium via microbial multiplication and migration; nonviable pathogens remained inside the filters. By assaying viable pathogens using real-time PCRs, multiple species of foodborne pathogens were detected, including L. monocytogenes, Salmonella enterica, and Escherichia coli O157:H7, at around 1 CFU/ml or 1 CFU/g in various food samples. This filter-based pathogen enrichment technology is a unique bacterial enrichment alternative to the conventional culture enrichment step and can significantly shorten the time necessary to obtain assay results.
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Clay, Patrick A., Meghan A. Duffy, and Volker H. W. Rudolf. "Within-host priority effects and epidemic timing determine outbreak severity in co-infected populations." Proceedings of the Royal Society B: Biological Sciences 287, no. 1922 (March 4, 2020): 20200046. http://dx.doi.org/10.1098/rspb.2020.0046.
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Co-infections of hosts by multiple pathogen species are ubiquitous, but predicting their impact on disease remains challenging. Interactions between co-infecting pathogens within hosts can alter pathogen transmission, with the impact on transmission typically dependent on the relative arrival order of pathogens within hosts (within-host priority effects). However, it is unclear how these within-host priority effects influence multi-pathogen epidemics, particularly when the arrival order of pathogens at the host-population scale varies. Here, we combined models and experiments with zooplankton and their naturally co-occurring fungal and bacterial pathogens to examine how within-host priority effects influence multi-pathogen epidemics. Epidemiological models parametrized with within-host priority effects measured at the single-host scale predicted that advancing the start date of bacterial epidemics relative to fungal epidemics would decrease the mean bacterial prevalence in a multi-pathogen setting, while models without within-host priority effects predicted the opposite effect. We tested these predictions with experimental multi-pathogen epidemics. Empirical dynamics matched predictions from the model including within-host priority effects, providing evidence that within-host priority effects influenced epidemic dynamics. Overall, within-host priority effects may be a key element of predicting multi-pathogen epidemic dynamics in the future, particularly as shifting disease phenology alters the order of infection within hosts.
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Qiao, Yongli, Rui Xia, Jixian Zhai, Yingnan Hou, Li Feng, Yi Zhai, and Wenbo Ma. "Small RNAs in Plant Immunity and Virulence of Filamentous Pathogens." Annual Review of Phytopathology 59, no. 1 (August 25, 2021): 265–88. http://dx.doi.org/10.1146/annurev-phyto-121520-023514.
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Gene silencing guided by small RNAs governs a broad range of cellular processes in eukaryotes. Small RNAs are important components of plant immunity because they contribute to pathogen-triggered transcription reprogramming and directly target pathogen RNAs. Recent research suggests that silencing of pathogen genes by plant small RNAs occurs not only during viral infection but also in nonviral pathogens through a process termed host-induced gene silencing, which involves trans-species small RNA trafficking. Similarly, small RNAs are also produced by eukaryotic pathogens and regulate virulence. This review summarizes the small RNA pathways in both plants and filamentous pathogens, including fungi and oomycetes, and discusses their role in host–pathogen interactions. We highlight secondarysmall interfering RNAs of plants as regulators of immune receptor gene expression and executors of host-induced gene silencing in invading pathogens. The current status and prospects of trans-species gene silencing at the host–pathogen interface are discussed.
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Chen, Shanshan, Yijun Ran, Hebo Huang, Zhenzhen Wang, and Ke-ke Shang. "Epidemic Dynamics of Two-Pathogen Spreading for Pairwise Models." Mathematics 10, no. 11 (June 2, 2022): 1906. http://dx.doi.org/10.3390/math10111906.
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In the real world, pathogens do not exist in isolation. The transmission of one pathogen may be affected by the presence of other pathogens, and certain pathogens generate multiple strains with different spreading features. Hence, the behavior of multi-pathogen transmission has attracted much attention in epidemiological research. In this paper, we use the pairwise approximation method to formulate two-pathogen models capturing cross-immunity, super-infection, and co-infection phenomena, in which each pathogen follows a susceptible-infected-susceptible (SIS) mechanism. For each model, we calculate the basic reproduction number and analyze the stability of equilibria, and discuss the differences from the mean-field approach. We demonstrate that simulations are in good agreement with the analytical results.
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WACHTEL, MARIAN R., JAMES L. McEVOY, YAGUANG LUO, ANISHA M. WILLIAMS-CAMPBELL, and MORSE B. SOLOMON. "Cross-Contamination of Lettuce (Lactuca sativa L.) with Escherichia coli O157:H7 via Contaminated Ground Beef†." Journal of Food Protection 66, no. 7 (July 1, 2003): 1176–83. http://dx.doi.org/10.4315/0362-028x-66.7.1176.
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A lettuce outbreak strain of E. coli O157:H7 was used to quantitate the pathogen's survival in ground beef and its transfer to hands, cutting board surfaces, and lettuce. Overnight storage of inoculated beef at 4°C resulted in no pathogen growth, while room-temperature storage allowed multiplication. Hamburger patty formation allowed the transfer of bacteria to hands. Contaminated fingers subsequently transferred the pathogen to lettuce during handling. E. coli was transferred from hamburgers to cutting board surfaces; overnight storage of boards decreased the numbers of recoverable pathogens by ~1 log CFU. A 15-s water rinse failed to remove significant numbers of pathogens from cutting boards whether it was applied immediately after contamination or following overnight room-temperature storage. Three lettuce leaves were successively applied to a single contaminated cutting board area both immediately after contamination and after overnight room-temperature storage of contaminated boards. Another set of leaves was pressed onto boards immediately following contamination and was then stored overnight at 4°C before pathogen enumeration. The numbers of pathogens transferred to the first pressed leaves were larger than those transferred to the second or third leaves. There were no significant differences in the numbers of pathogens recovered from leaves pressed immediately after contamination whether pathogens were enumerated immediately or following overnight storage at 4°C. However, fewer pathogens were transferred to leaves pressed to boards stored overnight at room temperature prior to contact with lettuce. Twenty-five lettuce pieces were successively pressed onto one area on a board containing 1.25 × 102 CFU of E. coli. Pathogens were transferred to 46% of the leaves, including the 25th exposed leaf.
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Gallet, Romain, Colin Fontaine, François Bonnot, Joëlle Milazzo, Christophe Tertois, Henri Adreit, Virginie Ravigné, Elisabeth Fournier, and Didier Tharreau. "Evolution of Compatibility Range in the Rice−Magnaporthe oryzae System: An Uneven Distribution of R Genes Between Rice Subspecies." Phytopathology® 106, no. 4 (April 2016): 348–54. http://dx.doi.org/10.1094/phyto-07-15-0169-r.
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Efficient strategies for limiting the impact of pathogens on crops require a good understanding of the factors underlying the evolution of compatibility range for the pathogens and host plants, i.e., the set of host genotypes that a particular pathogen genotype can infect and the set of pathogen genotypes that can infect a particular host genotype. Until now, little is known about the evolutionary and ecological factors driving compatibility ranges in systems implicating crop plants. We studied the evolution of host and pathogen compatibility ranges for rice blast disease, which is caused by the ascomycete Magnaporthe oryzae. We challenged 61 rice varieties from three rice subspecies with 31 strains of M. oryzae collected worldwide from all major known genetic groups. We determined the compatibility range of each plant variety and pathogen genotype and the severity of each plant−pathogen interaction. Compatibility ranges differed between rice subspecies, with the most resistant subspecies selecting for pathogens with broader compatibility ranges and the least resistant subspecies selecting for pathogens with narrower compatibility ranges. These results are consistent with a nested distribution of R genes between rice subspecies.
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Tsai, Kevin, Sheillah Simiyu, Jane Mumma, Rose Aseyo, Oliver Cumming, Robert Dreibelbis, and Kelly Baker. "Enteric Pathogen Diversity in Infant Foods in Low-Income Neighborhoods of Kisumu, Kenya." International Journal of Environmental Research and Public Health 16, no. 3 (February 12, 2019): 506. http://dx.doi.org/10.3390/ijerph16030506.
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Pediatric diarrheal disease remains the second most common cause of preventable illness and death among children under the age of five, especially in low and middle-income countries (LMICs). However, there is limited information regarding the role of food in pathogen transmission in LMICs. For this study, we examined the frequency of enteric pathogen occurrence and co-occurrence in 127 infant weaning foods in Kisumu, Kenya, using a multi-pathogen PCR diagnostic tool, and assessed household food hygiene risk factors for contamination. Bacterial, viral, and protozoan enteric pathogen DNA and RNA were detected in 62% of the infant weaning food samples collected, with 37% of foods containing more than one pathogen type. Multivariable generalized linear mixed model analysis indicated type of infant food best explained the presence and diversity of enteric pathogens in infant food, while most household food hygiene risk factors considered in this study were not significantly associated with pathogen contamination. Specifically, cow’s milk was significantly more likely to contain a pathogen (adjusted risk ratio = 14.4; 95% confidence interval (CI) 1.78–116.1) and more likely to have higher number of enteric pathogen species (adjusted risk ratio = 2.35; 95% CI 1.67–3.29) than porridge. Our study demonstrates that infants in this low-income urban setting are frequently exposed to diarrhoeagenic pathogens in food and suggests that interventions are needed to prevent foodborne transmission of pathogens to infants.
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Kumar, Himanshu, Taro Kawai, and Shizuo Akira. "Pathogen recognition in the innate immune response." Biochemical Journal 420, no. 1 (April 28, 2009): 1–16. http://dx.doi.org/10.1042/bj20090272.
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Immunity against microbial pathogens primarily depends on the recognition of pathogen components by innate receptors expressed on immune and non-immune cells. Innate receptors are evolutionarily conserved germ-line-encoded proteins and include TLRs (Toll-like receptors), RLRs [RIG-I (retinoic acid-inducible gene-I)-like receptors] and NLRs (Nod-like receptors). These receptors recognize pathogens or pathogen-derived products in different cellular compartments, such as the plasma membrane, the endosomes or the cytoplasm, and induce the expression of cytokines, chemokines and co-stimulatory molecules to eliminate pathogens and instruct pathogen-specific adaptive immune responses. In the present review, we will discuss the recent progress in the study of pathogen recognition by TLRs, RLRs and NLRs and their signalling pathways.
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Recart, Wilnelia, Rover Bernhard, Isabella Ng, Katherine Garcia, and Arietta E. Fleming-Davies. "Meta-Analysis of the Effects of Insect Pathogens: Implications for Plant Reproduction." Pathogens 12, no. 2 (February 18, 2023): 347. http://dx.doi.org/10.3390/pathogens12020347.
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Despite extensive work on both insect disease and plant reproduction, there is little research on the intersection of the two. Insect-infecting pathogens could disrupt the pollination process by affecting pollinator population density or traits. Pathogens may also infect insect herbivores and change herbivory, potentially altering resource allocation to plant reproduction. We conducted a meta-analysis to (1) summarize the literature on the effects of pathogens on insect pollinators and herbivores and (2) quantify the extent to which pathogens affect insect traits, with potential repercussions for plant reproduction. We found 39 articles that fit our criteria for inclusion, extracting 218 measures of insect traits for 21 different insect species exposed to 25 different pathogens. We detected a negative effect of pathogen exposure on insect traits, which varied by host function: pathogens had a significant negative effect on insects that were herbivores or carried multiple functions but not on insects that solely functioned as pollinators. Particular pathogen types were heavily studied in certain insect orders, with 7 of 11 viral pathogen studies conducted in Lepidoptera and 5 of 9 fungal pathogen studies conducted in Hymenoptera. Our results suggest that most studies have focused on a small set of host–pathogen pairs. To understand the implications for plant reproduction, future work is needed to directly measure the effects of pathogens on pollinator effectiveness.
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Lloyd-Smith, James O. "Vacated niches, competitive release and the community ecology of pathogen eradication." Philosophical Transactions of the Royal Society B: Biological Sciences 368, no. 1623 (August 5, 2013): 20120150. http://dx.doi.org/10.1098/rstb.2012.0150.
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A recurring theme in the epidemiological literature on disease eradication is that each pathogen occupies an ecological niche, and eradication of one pathogen leaves a vacant niche that favours the emergence of new pathogens to replace it. However, eminent figures have rejected this view unequivocally, stating that there is no basis to fear pathogen replacement and even that pathogen niches do not exist. After exploring the roots of this controversy, I propose resolutions to disputed issues by drawing on broader ecological theory, and advance a new consensus based on robust mechanistic principles. I argue that pathogen eradication (and cessation of vaccination) leads to a ‘vacated niche’, which could be re-invaded by the original pathogen if introduced. Consequences for other pathogens will vary, with the crucial mechanisms being competitive release, whereby the decline of one species allows its competitors to perform better, and evolutionary adaptation. Hence, eradication can cause a quantitative rise in the incidence of another infection, but whether this leads to emergence as an endemic pathogen depends on additional factors. I focus on the case study of human monkeypox and its rise following smallpox eradication, but also survey how these ideas apply to other pathogens and discuss implications for eradication policy.
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Heck, Michelle. "Insect Transmission of Plant Pathogens: a Systems Biology Perspective." mSystems 3, no. 2 (March 20, 2018): e00168-17. http://dx.doi.org/10.1128/msystems.00168-17.
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ABSTRACT Insect-vectored pathogens pose one of the greatest threats to plant and animal, including human, health on a global scale. Few effective control strategies have been developed to thwart the transmission of any insect-transmitted pathogen. Most have negative impacts on the environment and human health and are unsustainable. Plant pathogen transmission by insect vectors involves a combination of coevolving biological players: plant hosts, insect vectors, plant pathogens, and bacterial endosymbionts harbored by the insect. Our ability to help growers to control vector-borne disease depends on our ability to generate pathogen- and/or disease-resistant crops by traditional or synthetic approaches and to block pathogen transmission by the insect vector. Systems biology studies have led to the reexamination of existing paradigms on how pathogens interact with insect vectors, including the bacterial symbionts, and have identified vector-pathogen interactions at the molecular and cellular levels for the development of novel transmission interdiction strategies.
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Veresoglou, Stavros D., and Matthias C. Rillig. "Suppression of fungal and nematode plant pathogens through arbuscular mycorrhizal fungi." Biology Letters 8, no. 2 (October 19, 2011): 214–17. http://dx.doi.org/10.1098/rsbl.2011.0874.
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Arbuscular mycorrhizal (AM) fungi represent ubiquitous mutualists of terrestrial plants. Through the symbiosis, plant hosts, among other benefits, receive protection from pathogens. A meta-analysis was conducted on 106 articles to determine whether, following pathogen infection of AM-colonized plants, the identity of the organisms involved (pathogens, AM fungi and host plants) had implications for the extent of the AM-induced pathogen suppression. Data on fungal and nematode pathogens were analysed separately. Although we found no differences in AM effectiveness with respect to the identity of the plant pathogen, the identity of the AM isolate had a dramatic effect on the level of pathogen protection. AM efficiency differences with respect to nematode pathogens were mainly limited to the number of AM isolates present; by contrast, modification of the ability to suppress fungal pathogens could occur even through changing the identity of the Glomeraceae isolate applied. N-fixing plants received more protection from fungal pathogens than non-N-fixing dicotyledons; this was attributed to the more intense AM colonization in N-fixing plants. Results have implications for understanding mycorrhizal ecology and agronomic applications.
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Magunda, Forgivemore, Chelsea Wright Thompson, David A. Schneider, and Susan M. Noh. "Anaplasma marginale Actively Modulates Vacuolar Maturation during Intracellular Infection of Its Tick Vector, Dermacentor andersoni." Applied and Environmental Microbiology 82, no. 15 (May 27, 2016): 4715–31. http://dx.doi.org/10.1128/aem.01030-16.
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ABSTRACTTick-borne transmission of bacterial pathogens in the orderRickettsialesis responsible for diverse infectious diseases, many of them severe, in humans and animals. Transmission dynamics differ among these pathogens and are reflected in the pathogen-vector interaction.Anaplasma marginalehas been shown to establish and maintain infectivity withinDermacentorspp. for weeks to months while escaping the complex network of vacuolar peptidases that are responsible for digestion of the tick blood meal. How this prolonged maintenance of infectivity in a potentially hostile environment is achieved has been unknown. Using the natural vectorDermacentor andersoni, we demonstrated thatA. marginale-infected tick vacuoles (AmVs) concurrently recruit markers of the early endosome (Rab5), recycling endosome (Rab4 and Rab11), and late endosome (Rab7), are maintained near neutral pH, do not fuse with lysosomes, exclude the protease cathepsin L, and engage the endoplasmic reticulum and Golgi apparatus for up to 21 days postinfection. Maintenance of this safe vacuolar niche requires activeA. marginaleprotein synthesis; in its absence, the AmVs mature into acidic, protease-active phagolysosomes. Identification of this bacterially directed modeling of the tick midgut endosome provides a mechanistic basis for examination of the differences in transmission efficiency observed amongA. marginalestrains and among vector populations.IMPORTANCETicks transmit a variety of intracellular bacterial pathogens that cause significant diseases in humans and animals. For successful transmission, these bacterial pathogens must first gain entry into the tick midgut digestive cells, avoid digestion, and establish a replicative niche without harming the tick vector. Little is known about how this replicative niche is established and maintained. Using the ruminant pathogenA. marginaleand its natural tick vector,D. andersoni, this study characterized the features of theA. marginaleniche in the tick midgut and demonstrates thatA. marginaleprotein synthesis is required for the maintenance of this niche. This work opens a new line of inquiry about the pathogen effectors and their targets within the tick that mediate tick-pathogen interactions and ultimately serve as the determinants of pathogen success.
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Kang, Seogchan, Jaime E. Blair, David M. Geiser, Chang-Hyun Khang, Sook-Young Park, Mark Gahegan, Kerry O'Donnell, et al. "Plant Pathogen Culture Collections: It Takes a Village to Preserve These Resources Vital to the Advancement of Agricultural Security and Plant Pathology." Phytopathology® 96, no. 9 (September 2006): 920–25. http://dx.doi.org/10.1094/phyto-96-0920.
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Plant pathogen culture collections are essential resources in our fight against plant disease and for connecting discoveries of the present with established knowledge of the past. However, available infrastructure in support of culture collections is in serious need of improvement, and we continually face the risk of losing many of these collections. As novel and reemerging plant pathogens threaten agriculture, their timely identification and monitoring depends on rapid access to cultures representing the known diversity of plant pathogens along with genotypic, phenotypic, and epidemiological data associated with them. Archiving such data in a format that can be easily accessed and searched is essential for rapid assessment of potential risk and can help track the change and movement of pathogens. The underexplored pathogen diversity in nature further underscores the importance of cataloguing pathogen cultures. Realizing the potential of pathogen genomics as a foundation for developing effective disease control also hinges on how effectively we use the sequenced isolate as a reference to understand the genetic and phenotypic diversity within a pathogen species. In this letter, we propose a number of measures for improving pathogen culture collections.
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KNIPL, DIÁNA, and SEYED M. MOGHADAS. "COMPARATIVE DYNAMICS OF MONOVALENT AND BIVALENT VACCINATION FOR IMMUNOLOGICALLY UNRELATED PATHOGENS." Journal of Biological Systems 24, no. 01 (March 2016): 91–115. http://dx.doi.org/10.1142/s0218339016500054.
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Multivalent vaccines are designed to immunize against two or more pathogens in a single dose vaccination. A challenge for wide spread use of these vaccines is their lower protection efficacy compared to monovalent vaccines that immunize individuals against a single pathogen. We sought, for the first time, to evaluate the outcomes of bivalent and monovalent vaccines in terms of the reduction in the number of infections over time. For this evaluation, we developed epidemiological models governing the transmission dynamics of two immunologically unrelated pathogens, where immunity conferred by vaccination or natural infection of one pathogen does not provide any cross-protection against the other pathogen. We assumed that a monovalent vaccine provides full, but temporary, protection against a particular pathogen. While protecting against both pathogens requires two pathogen-specific monovalent vaccines, a single dose of the bivalent vaccine provides partial protection against both pathogens. We analyzed the two models to investigate the impact of vaccination. In addition to examining global behaviors and disease persistence of the models, we performed simulations to show the existence of a biologically feasible region for the bivalent vaccine to outperform monovalent vaccines for prevention of disease transmission using a lower number of vaccines.
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Harwood, Catherine, and Reeta Rao. "Host Pathogen Relations: Exploring Animal Models for Fungal Pathogens." Pathogens 3, no. 3 (June 30, 2014): 549–62. http://dx.doi.org/10.3390/pathogens3030549.
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Rovenich, Hanna, Jordi C. Boshoven, and Bart PHJ Thomma. "Filamentous pathogen effector functions: of pathogens, hosts and microbiomes." Current Opinion in Plant Biology 20 (August 2014): 96–103. http://dx.doi.org/10.1016/j.pbi.2014.05.001.
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Young, John A. T. "PLoS Pathogens—A High-Impact Journal for Pathogen Research." PLoS Pathogens 1, no. 1 (2005): e12. http://dx.doi.org/10.1371/journal.ppat.0010012.
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Catanzariti, Ann-Maree, and David A. Jones. "Effector proteins of extracellular fungal plant pathogens that trigger host resistance." Functional Plant Biology 37, no. 10 (2010): 901. http://dx.doi.org/10.1071/fp10077.
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An understanding of the molecular mechanisms that plant pathogens use to successfully colonise host tissue can be gained by studying the biological activity of pathogen proteins secreted during infection. Several secreted ‘effector’ proteins with possible roles in virulence have been isolated from extracellular fungal pathogens, including three that have been shown to negate host defences. In most cases, significant effector variation is observed between different pathogen isolates, driven by the recognitional capacity of disease resistance proteins arrayed against the pathogen by the host plant. This review summarises what is known about the expression, function and variation of effectors isolated from extracellular fungal pathogens.
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Brugman, E., A. Widiastuti, and A. Wibowo. "Population genetics of Phytophthora species based on short sequence repeat (SSR) marker: a review of its importance and recent studies." IOP Conference Series: Earth and Environmental Science 1230, no. 1 (September 1, 2023): 012102. http://dx.doi.org/10.1088/1755-1315/1230/1/012102.
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Abstract Phytophthora is a genus of oomycete (water molds) whose member species mostly live as plant pathogens and have been reported to cause enormous economic losses on crops worldwide. In recent years, population genetics of Phytophthora pathogens have been broadly studied to evaluate their adaptive evolution. Population genetic studies focus on analyzing the level of genetic diversity and the structure of the pathogen population. A population’s genetic diversity is proportional to its evolutionary potential. The generation and maintenance of genetic variation in pathogen populations are influenced by the biology of the pathogen and its host, environments, agricultural practices, and human activities. Understanding the population genetics of plant pathogens allows us to track the dynamic of the pathogen population and their adaptive ability, assisting the development of sustainable disease management strategies. This review presents the importance of population genetics, short sequence repeat (SSR) marker utilization in population genetic studies, and recent population genetics studies of Phytophthora pathogens related to agricultural practices.
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Kumar, Ankit, Priyanshu Srivastava, PDNN Sirisena, Sunil Dubey, Ramesh Kumar, Jatin Shrinet, and Sujatha Sunil. "Mosquito Innate Immunity." Insects 9, no. 3 (August 8, 2018): 95. http://dx.doi.org/10.3390/insects9030095.
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Mosquitoes live under the endless threat of infections from different kinds of pathogens such as bacteria, parasites, and viruses. The mosquito defends itself by employing both physical and physiological barriers that resist the entry of the pathogen and the subsequent establishment of the pathogen within the mosquito. However, if the pathogen does gain entry into the insect, the insect mounts a vigorous innate cellular and humoral immune response against the pathogen, thereby limiting the pathogen’s propagation to nonpathogenic levels. This happens through three major mechanisms: phagocytosis, melanization, and lysis. During these processes, various signaling pathways that engage intense mosquito–pathogen interactions are activated. A critical overview of the mosquito immune system and latest information about the interaction between mosquitoes and pathogens are provided in this review. The conserved, innate immune pathways and specific anti-pathogenic strategies in mosquito midgut, hemolymph, salivary gland, and neural tissues for the control of pathogen propagation are discussed in detail.
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Penman, Bridget S., and Sunetra Gupta. "Detecting signatures of past pathogen selection on human HLA loci: are there needles in the haystack?" Parasitology 145, no. 6 (August 15, 2017): 731–39. http://dx.doi.org/10.1017/s0031182017001159.
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AbstractHuman leucocyte antigens (HLAs) are responsible for the display of peptide fragments for recognition by T-cell receptors. The gene family encoding them is thus integral to human adaptive immunity, and likely to be under strong pathogen selection. Despite this, it has proved difficult to demonstrate specific examples of pathogen–HLA coevolution. Selection from multiple pathogens simultaneously could explain why the evolutionary signatures of particular pathogens on HLAs have proved elusive. Here, we present an individual-based model of HLA evolution in the presence of two mortality-causing pathogens. We demonstrate that it is likely that individual pathogen species causing high mortality have left recognizable signatures on the HLA genomic region, despite more than one pathogen being present. Such signatures are likely to exist at the whole-population level, and involve haplotypic combinations of HLA genes rather than single loci.
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Tarchevsky, I. A. "Biogenic stress in plants." Kazan medical journal 75, no. 1 (January 15, 1994): 3–9. http://dx.doi.org/10.17816/kazmj89581.
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The picture of the pathogens and plant interaction is presented. That is: recognition; the influence of different hydrolases produced by pathogens on plant biopolimers and lipids; elicitors and phytoalexins formation; pathogen-induced proteins synthesis in plants; induction of supersensitivity in cells, surrounding the pathogen infection area; the influence of plant enzymes and toxins on pathogens and finally working out plant tissues resistance against pathogens (viruses, bacteria and fungi).
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Meyer, Thomas F. "Pathogenic Neisseriae: Complexity of Pathogen‐Host Cell Interplay." Clinical Infectious Diseases 28, no. 3 (March 1999): 433–41. http://dx.doi.org/10.1086/515160.
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Carter, Chris. "Alzheimer's Disease: APP, Gamma Secretase, APOE, CLU, CR1, PICALM, ABCA7, BIN1, CD2AP, CD33, EPHA1, and MS4A2, and Their Relationships with Herpes Simplex,C. Pneumoniae, Other Suspect Pathogens, and the Immune System." International Journal of Alzheimer's Disease 2011 (2011): 1–34. http://dx.doi.org/10.4061/2011/501862.
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Alzheimer's disease susceptibility genes, APP and gamma-secretase, are involved in the herpes simplex life cycle, and that of other suspect pathogens (C. pneumoniae,H. pylori,C. neoformans,B. burgdorferri,P. gingivalis) or immune defence. Such pathogens promote beta-amyloid deposition andtauphosphorylation and may thus be causative agents, whose effects are conditioned by genes. The antimicrobial effects of beta-amyloid, the localisation of APP/gamma-secretase in immunocompetent dendritic cells, and gamma secretase cleavage of numerous pathogen receptors suggest that this network is concerned with pathogen disposal, effects which may be abrogated by the presence of beta-amyloid autoantibodies in the elderly. These autoantibodies, as well as those to nerve growth factor andtau, also observed in Alzheimer's disease, may well be antibodies to pathogens, due to homology between human autoantigens and pathogen proteins. NGF ortauantibodies promote beta-amyloid deposition, neurofibrillary tangles, or cholinergic neuronal loss, and, with other autoantibodies, such as anti-ATPase, are potential agents of destruction, whose formation is dictated by sequence homology between pathogen and human proteins, and thus by pathogen strain and human genes. Pathogen elimination in the ageing population and removal of culpable autoantibodies might reduce the incidence and offer hope for a cure in this affliction.
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Moore, Sean M., Elizabeth T. Borer, and Parviez R. Hosseini. "Predators indirectly control vector-borne disease: linking predator–prey and host–pathogen models." Journal of The Royal Society Interface 7, no. 42 (May 27, 2009): 161–76. http://dx.doi.org/10.1098/rsif.2009.0131.
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Pathogens transmitted by arthropod vectors are common in human populations, agricultural systems and natural communities. Transmission of these vector-borne pathogens depends on the population dynamics of the vector species as well as its interactions with other species within the community. In particular, predation may be sufficient to control pathogen prevalence indirectly via the vector. To examine the indirect effect of predators on vectored-pathogen dynamics, we developed a theoretical model that integrates predator–prey and host–pathogen theory. We used this model to determine whether predation can prevent pathogen persistence or alter the stability of host–pathogen dynamics. We found that, in the absence of predation, pathogen prevalence in the host increases with vector fecundity, whereas predation on the vector causes pathogen prevalence to decline, or even become extinct, with increasing vector fecundity. We also found that predation on a vector may drastically slow the initial spread of a pathogen. The predator can increase host abundance indirectly by reducing or eliminating infection in the host population. These results highlight the importance of studying interactions that, within the greater community, may alter our predictions when studying disease dynamics. From an applied perspective, these results also suggest situations where an introduced predator or the natural enemies of a vector may slow the rate of spread of an emerging vector-borne pathogen.
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Meylan, Sylvain, Ian W. Andrews, and James J. Collins. "Targeting Antibiotic Tolerance, Pathogen by Pathogen." Cell 172, no. 6 (March 2018): 1228–38. http://dx.doi.org/10.1016/j.cell.2018.01.037.
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Jones, Rodney P., and Andrey Ponomarenko. "Roles for Pathogen Interference in Influenza Vaccination, with Implications to Vaccine Effectiveness (VE) and Attribution of Influenza Deaths." Infectious Disease Reports 14, no. 5 (September 23, 2022): 710–58. http://dx.doi.org/10.3390/idr14050076.
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Pathogen interference is the ability of one pathogen to alter the course and clinical outcomes of infection by another. With up to 3000 species of human pathogens the potential combinations are vast. These combinations operate within further immune complexity induced by infection with multiple persistent pathogens, and by the role which the human microbiome plays in maintaining health, immune function, and resistance to infection. All the above are further complicated by malnutrition in children and the elderly. Influenza vaccination offers a measure of protection for elderly individuals subsequently infected with influenza. However, all vaccines induce both specific and non-specific effects. The specific effects involve stimulation of humoral and cellular immunity, while the nonspecific effects are far more nuanced including changes in gene expression patterns and production of small RNAs which contribute to pathogen interference. Little is known about the outcomes of vaccinated elderly not subsequently infected with influenza but infected with multiple other non-influenza winter pathogens. In this review we propose that in certain years the specific antigen mix in the seasonal influenza vaccine inadvertently increases the risk of infection from other non-influenza pathogens. The possibility that vaccination could upset the pathogen balance, and that the timing of vaccination relative to the pathogen balance was critical to success, was proposed in 2010 but was seemingly ignored. Persons vaccinated early in the winter are more likely to experience higher pathogen interference. Implications to the estimation of vaccine effectiveness and influenza deaths are discussed.
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SIMANEK, A. M., J. B. DOWD, A. ZAJACOVA, and A. E. AIELLO. "Unpacking the ‘black box’ of total pathogen burden: is number or type of pathogens most predictive of all-cause mortality in the United States?" Epidemiology and Infection 143, no. 12 (December 18, 2014): 2624–34. http://dx.doi.org/10.1017/s0950268814003215.
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SUMMARYA ‘black box’ paradigm has prevailed in which researchers have focused on the association between the total number of pathogens for which individuals are seropositive (i.e. total pathogen burden) and various chronic diseases, while largely ignoring the role that seropositivity for specific combinations of pathogens may play in the aetiology of such outcomes and consequently mortality. We examined the association between total pathogen burden as well as specific pathogen combinations and all-cause mortality in the United States. Data were from individuals aged ⩾25 years tested for cytomegalovirus (CMV), herpes simplex virus (HSV)-1, HSV-2 andHelicobacter pylori, with mortality follow-up to 31 December 2006 in the National Health and Nutrition Examination Survey (NHANES) III (N= 6522). We did not observe a statistically significant graded relationship between total pathogen burden level and all-cause mortality. Furthermore, compared to those seronegative for all four pathogens, the greatest statistically significant rate of all-cause mortality was for those CMV+/HSV-2+ (hazard ratio 1·95, 95% confidence interval 1·13–3·35) adjusting for age, gender, race/ethnicity, education level, body mass index (kg/m2) and smoking status. Interventions targeting prevention or treatment of particular pathogens may be more effective for reducing mortality than those focused solely on reducing overall pathogen burden.
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Laine, Anna-Liisa, Jeremy J. Burdon, Adnane Nemri, and Peter H. Thrall. "Host ecotype generates evolutionary and epidemiological divergence across a pathogen metapopulation." Proceedings of the Royal Society B: Biological Sciences 281, no. 1787 (July 22, 2014): 20140522. http://dx.doi.org/10.1098/rspb.2014.0522.
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The extent and speed at which pathogens adapt to host resistance varies considerably. This presents a challenge for predicting when—and where—pathogen evolution may occur. While gene flow and spatially heterogeneous environments are recognized to be critical for the evolutionary potential of pathogen populations, we lack an understanding of how the two jointly shape coevolutionary trajectories between hosts and pathogens. The rust pathogen Melampsora lini infects two ecotypes of its host plant Linum marginale that occur in close proximity yet in distinct populations and habitats. In this study, we found that within-population epidemics were different between the two habitats. We then tested for pathogen local adaptation at host population and ecotype level in a reciprocal inoculation study. Even after controlling for the effect of spatial structure on infection outcome, we found strong evidence of pathogen adaptation at the host ecotype level. Moreover, sequence analysis of two pathogen infectivity loci revealed strong genetic differentiation by host ecotype but not by distance. Hence, environmental variation can be a key determinant of pathogen population genetic structure and coevolutionary dynamics and can generate strong asymmetry in infection risks through space.
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Vögeli, Matthias, Jesús A. Lemus, David Serrano, Guillermo Blanco, and José L. Tella. "An island paradigm on the mainland: host population fragmentation impairs the community of avian pathogens." Proceedings of the Royal Society B: Biological Sciences 278, no. 1718 (January 26, 2011): 2668–76. http://dx.doi.org/10.1098/rspb.2010.1227.
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Emergent infectious diseases represent a major threat for biodiversity in fragmented habitat networks, but their dynamics in host metapopulations remain largely unexplored. We studied a large community of pathogens (including 26 haematozoans, bacteria and viruses as determined through polymerase chain reaction assays) in a highly fragmented mainland bird metapopulation. Contrary to recent studies, which have established that the prevalence of pathogens increase with habitat fragmentation owing to crowding and habitat-edge effects, the analysed pathogen parameters were neither dependent on host densities nor related to the spatial structure of the metapopulation. We provide, to our knowledge, the first empirical evidence for a positive effect of host population size on pathogen prevalence, richness and diversity. These new insights into the interplay between habitat fragmentation and pathogens reveal properties of a host–pathogen system resembling island environments, suggesting that severe habitat loss and fragmentation could lower pathogen pressure in small populations.
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Dallas, Tad A., Colin J. Carlson, and Timothée Poisot. "Testing predictability of disease outbreaks with a simple model of pathogen biogeography." Royal Society Open Science 6, no. 11 (November 2019): 190883. http://dx.doi.org/10.1098/rsos.190883.
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Predicting disease emergence and outbreak events is a critical task for public health professionals and epidemiologists. Advances in global disease surveillance are increasingly generating datasets that are worth more than their component parts for prediction-oriented work. Here, we use a trait-free approach which leverages information on the global community of human infectious diseases to predict the biogeography of pathogens through time. Our approach takes pairwise dissimilarities between countries’ pathogen communities and pathogens’ geographical distributions and uses these to predict country–pathogen associations. We compare the success rates of our model for predicting pathogen outbreak, emergence and re-emergence potential as a function of time (e.g. number of years between training and prediction), pathogen type (e.g. virus) and transmission mode (e.g. vector-borne). With only these simple predictors, our model successfully predicts basic network structure up to a decade into the future. We find that while outbreak and re-emergence potential are especially well captured by our simple model, prediction of emergence events remains more elusive, and sudden global emergences like an influenza pandemic are beyond the predictive capacity of the model. However, these stochastic pandemic events are unlikely to be predictable from such coarse data. Together, our model is able to use the information on the existing country–pathogen network to predict pathogen outbreaks fairly well, suggesting the importance in considering information on co-occurring pathogens in a more global view even to estimate outbreak events in a single location or for a single pathogen.
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A Burke, Beatrice. "Ureaplasma: An overlooked pathogen." Journal of Case Reports and Images in Obstetrics and Gynecology 9, no. 1 (February 21, 2023): 21–23. http://dx.doi.org/10.5348/100138z08bb2023cr.
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Ureaplasma is a less recognized pathogen found in women of all ages. Women with unexplained bladder pain, urethritis, or hematuria should be screened with an appropriate culture media; standard urine culture is not sufficient. When given antibiotics effective against ureaplasma (Doxycycline twice daily for at least a week) patients usually experience relief of symptoms within several days.
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Kachroo, Aardra, Paul Vincelli, and Pradeep Kachroo. "Signaling Mechanisms Underlying Resistance Responses: What Have We Learned, and How Is It Being Applied?" Phytopathology® 107, no. 12 (December 2017): 1452–61. http://dx.doi.org/10.1094/phyto-04-17-0130-rvw.
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Plants have evolved highly specific mechanisms to resist pathogens including preformed barriers and the induction of elaborate signaling pathways. Induced signaling requires recognition of the pathogen either via conserved pathogen-derived factors or specific pathogen-encoded proteins called effectors. Recognition of these factors by host encoded receptor proteins can result in the elicitation of different tiers of resistance at the site of pathogen infection. In addition, plants induce a type of systemic immunity which is effective at the whole plant level and protects against a broad spectrum of pathogens. Advances in our understanding of pathogen-recognition mechanisms, identification of the underlying molecular components, and their significant conservation across diverse plant species has enabled the development of novel strategies to combat plant diseases. This review discusses key advances in plant defense signaling that have been adapted or have the potential to be adapted for plant protection against microbial diseases.
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Melgar, Mario, Molly Lamb, Diva M. Calvimontes, Edwin J. Asturias, Ingrid Contreras-Roldan, Samuel Dominguez, Christine C. Robinson, Stephen Berman, and James Gaensbauer. "Enteropathogen Identification by Multiplex PCR in Guatemalan Children with Acute, Non-bloody Diarrhea." Open Forum Infectious Diseases 4, suppl_1 (2017): S361. http://dx.doi.org/10.1093/ofid/ofx163.877.
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Abstract Background Diarrhea is a leading cause of morbidity and mortality in children in low and middle income countries (LMICs). Assessing diarrhea etiology in LMICs is of great importance in order to better develop both therapeutic and public health strategies, but is hampered by the complexity of potential diarrheal pathogens, and diverse methodology needed for pathogen identification Methods Subjects 6 to 35 months old with acute, moderate severity, non-bloody diarrhea were enrolled in a diarrheal treatment trial, conducted at one rural (N = 172) and two urban sites (N = 144) in Guatemala. Diarrheal pathogens were determined in stool by multiplex PCR (FilmArray GI® Biofire) which allows simultaneous identification of 23 bacterial, viral, parasitic pathogens. Descriptive statistics on demographics, pathogen load, and differences in pathogen occurrence by site were performed; differences were assessed with t-test and chi2 test Results Nearly all (96.8%) subjects had pathogens identified, and most had multiple potential pathogens identified (mean pathogen count: 2.7 urban and 4.8 rural; P < 0.001 (Figure 1). Notable pathogen differences were observed between rural and urban populations. Bacteria (particularly E.coli pathotypes and Campylobacter) and protozoa (particularly giardia) were more common in the rural population (Figure2). Viral pathogens were either similar or more common (norovirus; P = 0.04) in the urban population; rotavirus was uncommon in both sites (10 rural and 12 urban cases). A similar pattern of pathogen evolution with patient age was noted in both settings, with a decrease in the relative number of viral and increase in parasitic pathogens (Figure 3). Important demographic and socioeconomic differences between rural and urban were noted: rural subjects had poorer nutritional status, underdeveloped water and sanitation facilities and more domestic animal exposure Conclusion Acute diarrheal episodes in Guatemalan children were associated with a complex spectrum of pathogens when determined by multiplex PCR, with distinct patterns in rural and urban populations. Future studies to precisely determine diarrheal etiologies in LMICs will need to incorporate controls to sort causative organisms from those colonizing the intestine. Disclosures All authors: No reported disclosures.