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Pathogen Exposure (pathogen + exposure)
Selected AbstractsInvertebrate immune systems , not homogeneous, not simple, not well understoodIMMUNOLOGICAL REVIEWS, Issue 1 2004Eric S Loker Summary:, The approximate 30 extant invertebrate phyla have diversified along separate evolutionary trajectories for hundreds of millions of years. Although recent work understandably has emphasized the commonalities of innate defenses, there is also ample evidence, as from completed genome studies, to suggest that even members of the same invertebrate order have taken significantly different approaches to internal defense. These data suggest that novel immune capabilities will be found among the different phyla. Many invertebrates have intimate associations with symbionts that may play more of a role in internal defense than generally appreciated. Some invertebrates that are either long lived or have colonial body plans may diversify components of their defense systems via somatic mutation. Somatic diversification following pathogen exposure, as seen in plants, has been investigated little in invertebrates. Recent molecular studies of sponges, cnidarians, shrimp, mollusks, sea urchins, tunicates, and lancelets have found surprisingly diversified immune molecules, and a model is presented that supports the adaptive value of diversified non-self recognition molecules in invertebrates. Interactions between invertebrates and viruses also remain poorly understood. As we are in the midst of alarming losses of coral reefs, increased pathogen challenge to invertebrate aquaculture, and rampant invertebrate-transmitted parasites of humans and domestic animals, we need a better understanding of invertebrate immunology. [source] Mating triggers dynamic immune regulations in wood ant queensJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 3 2009G. CASTELLA Abstract Mating can affect female immunity in multiple ways. On the one hand, the immune system may be activated by pathogens transmitted during mating, sperm and seminal proteins, or wounds inflicted by males. On the other hand, immune defences may also be down-regulated to reallocate resources to reproduction. Ants are interesting models to study post-mating immune regulation because queens mate early in life, store sperm for many years, and use it until their death many years later, while males typically die after mating. This long-term commitment between queens and their mates limits the opportunity for sexual conflict but raises the new constraint of long-term sperm survival. In this study, we examine experimentally the effect of mating on immunity in wood ant queens. Specifically, we compared the phenoloxidase and antibacterial activities of mated and virgin Formica paralugubris queens. Queens had reduced levels of active phenoloxidase after mating, but elevated antibacterial activity 7 days after mating. These results indicate that the process of mating, dealation and ovary activation triggers dynamic patterns of immune regulation in ant queens that probably reflect functional responses to mating and pathogen exposure that are independent of sexual conflict. [source] Toward quantifying the usage costs of human immunity: Altered metabolic rates and hormone levels during acute immune activation in menAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 4 2010Michael P. Muehlenbein There is a paucity of data on the energetic demands of human immune functions, despite the fact that both clinical medicine and evolutionary biology would benefit from further clarification of these costs. To better understand the energetic requirements of mounting a mild immune response, as well as some of the major hormonal changes underlying these metabolic changes, we examined changes in resting metabolic rate (RMR) and hormones during and after respiratory tract infection in young adult men. An epidemiologic passive detection design was used to recruit 25 nonfebrile subjects naturally infected with respiratory tract pathogens. Symptomology, percent body fat, RMR, salivary testosterone and cortisol, and other information were collected at a minimum of three time points during and after convalescence. Comparisons of the differences in RMR, testosterone, and cortisol between sampling days within individual cases were made using paired t -tests. Participants experienced 8% higher RMR during illness, and a subset of these men experienced a mean increase greater than 14%. The participants also experienced 10% lower testosterone levels during illness, and a subset of these participants experienced a mean decrease of 30%, although cortisol levels did not change significantly. These results document elevated RMR following natural pathogen exposure in adult humans, demonstrating that even mild immune reactions can elicit significant increases in energy expenditure. Understanding the costs of immunity and the immunomodulatory actions of hormones are central to understanding the role of immunity in human life history evolution. Am. J. Hum. Biol. 2010. © 2010 Wiley-Liss, Inc. [source] Androgens and energy allocation: Quasi-experimental evidence for effects of influenza vaccination on men's testosteroneAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 1 2009Zachary L. Simmons Androgens are proposed to allocate finite energetic resources away from immune function and toward anabolic processes related to reproductive effort. In situations of pathogen exposure, the significant energetic demands associated with mounting an immune response are expected to produce a decrease in androgen levels and commensurate redistribution of energy. We tested the hypothesis that even the mild immune challenge associated with vaccination may cause a decline in men's testosterone. As predicted, men who received an influenza vaccination exhibited a more negative change in testosterone over a 2-week period than did men in a nonequivalent control group who were not vaccinated. These results suggest that men's androgen concentrations may be finely calibrated to trade-offs between the energetic demands of immune responses and other life history problems. Am. J. Hum. Biol., 2009. © 2008 Wiley-Liss, Inc. [source] Resistance to chytridiomycosis varies among amphibian species and is correlated with skin peptide defensesANIMAL CONSERVATION, Issue 4 2007D. C. Woodhams Abstract Innate immune mechanisms of defense are especially important to ectothermic vertebrates in which adaptive immune responses may be slow to develop. One innate defense in amphibian skin is the release of abundant quantities of antimicrobial peptides. Chytridiomycosis is an emerging infectious disease of amphibians caused by the skin fungus, Batrachochytrium dendrobatidis. Susceptibility to chytridiomycosis varies among species, and mechanisms of disease resistance are not well understood. Previously, we have shown that Australian and Panamanian amphibian species that possess skin peptides that effectively inhibit the growth of B. dendrobatidis in vitro tend to survive better in the wild or are predicted to survive the first encounter with this lethal pathogen. For most species, it has been difficult to experimentally infect individuals with B. dendrobatidis and directly evaluate both survival and antimicrobial peptide defenses. Here, we demonstrate differences in susceptibility to chytridiomycosis among four Australian species (Litoria caerulea, Litoria chloris, Mixophyes fasciolatus and Limnodynastes tasmaniensis) after experimental infection with B. dendrobatidis, and show that the survival rate increases with the in vitro effectiveness of the skin peptides. We also observed that circulating granulocyte, but not lymphocyte, counts differed between infected and uninfected Lit. chloris. This suggests that innate granulocyte defenses may be activated by pathogen exposure. Taken together, our data suggest that multiple innate defense mechanisms are involved in resistance to chytridiomycosis, and the efficacy of these defenses varies by amphibian species. [source] Enhancement of the innate immune system and disease-resistant activity in Cyprinus carpio by oral administration of ,-glucan and whole cell yeastAQUACULTURE RESEARCH, Issue 6 2010Ayyaru Gopalakannan Abstract The effects of dietary ,- (1,3) glucan and whole cell yeast (Sacharomyces uvarum) on the immune response and disease resistance to Aeromonas hydrophila were investigated in Cyprinus carpio. ,-(1,3) glucan was extracted from the yeast. Both ,-(1,3) glucan and whole yeast were incorporated into the diet at 1% level and fed to common carp C. carpio for a period of 60 days. Control and treated fish were exposed to A. hydrophila on the 30th and the 60th day of the experimental period. Dietary supplementation of glucan significantly increased the white blood cell count in fish on the 60th day (2.91±0.04 × 104), and the highest nuetrophil nitro blue tetrazolium (NBT) activity was also observed in glucan-fed fish (30th day). A consistent increase in neutrophil (NBT) activity was also observed in whole cell fed fish until the end of the experiment. Similarly, ,-(1,3) glucan and whole cell yeast enhanced the serum lysozyme activity from the 15th day onwards but higher activity was reported on the 30th day in glucan and the 60th day in whole cell yeast-fed fish. Suplementation of ,-(1,3) glucan protected the fish from A. hydrophila infection. Nearly 75,80% of the fish survived pathogen exposure (relative percentage survival). However, only 54,60% survival was observed in the whole cell-fed fish. ,-(1,3) glucan and whole cell yeast protect the fish from pathogens by enhancing the cellular and humoral immune response in C. carpio. [source] How to kill a mocking bug?CELLULAR MICROBIOLOGY, Issue 4 2006Vitor B. Pinheiro Summary All metazoans have evolved means to protect themselves from threats present in the environment: injuries, viruses, fungi, bacteria and other parasites. Insect protection includes innate physical barriers and both cellular and humoral responses. The insect innate immune response, best characterized in Drosophila melanogaster, is a rapid broad response, triggered by pathogen-associated molecular patterns (PAMPs) recognition, which produces a limited range of effectors that does not alter upon continued pathogen exposure and lacks immunological memory. The Drosophila response, particularly its humoral response, has been investigated by both low and high-throughput methods. Three signalling pathways conserved between insects and mammals have been implicated in this response: Toll (equivalent to mammalian TLR), Imd (equivalent to TNF,) and Hop (equivalent to JAK/STAT). This review provides an entry point to the insect immune system literature outlining the main themes in D. melanogaster bacterial pathogen detection and humoral and cellular immune responses. The Drosophila immune response is compared with other insects and the mammalian immune system. [source] Occupational exposure to blood and body fluids among health care workers in a general hospital, ChinaAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 2 2009Min Zhang BM Abstract Objectives To understand current status of occupational exposure to blood and body fluids (BBF), and awareness of knowledge about occupational bloodborne pathogen exposures and universal precaution among hospital-based health care workers (HCWs). Methods A cross-sectional study was conducted during April to May 2004 to study incidence of occupational exposure to BBF among 1,144 hospital-based HCWs. Results The total incidence and the average number of episodes exposure to BBF was 66.3/100 HCWs per year and 7.5 per person per year in the past year, respectively. The incidence (per 100/HCWs per year) and the average number of episodes (per HCW per year) of percutaneous injury (PCI), mucous-membrane exposure (MME), and exposure to BBF by damaged skin was 50.3 and 1.8; 34.4 and 1.7; and 37.9 and 4.0, respectively. The leading incidence and the average number of episodes of PCI occurred in delivery room (82.6 and 1.8). The highest percentage of PCI's that occurred during the previous 2 weeks occurred during a surgical operation (22.8%). Of all sharp instruments, the suture needle contributed the highest percentage of PCI's (24.7%) among HCWs in the last 2 weeks. Over two-thirds (68.3%) of respondents were immunized with Hepatitis B vaccine; less than one-half (47%) of HCWs wore gloves while doing procedures on patients. The respondents demonstrated a lack of knowledge regarding transmission of bloodborne diseases and universal precautions. Conclusions Risk for potential exposure to BBF appears high in HCWs, and almost all of episodes are not reported. It is urgent to establish the Guideline for Prevention and Control of Occupational Exposure to Bloodborne Pathogens among HCWs. Am. J. Ind. Med. 52:89,98, 2009. © 2008 Wiley-Liss, Inc. [source] | |||||||||||||