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Parasite Burden (parasite + burden)
Selected AbstractsIL-4,/, mice with lethal Mesocestoides corti infections , reduced Th2 cytokines and alternatively activated macrophagesPARASITE IMMUNOLOGY, Issue 12 2009A. E. O'CONNELL Summary Protection against Mesocestoides corti, a cestode that invades vital organs, is dependent on the production of IL-4, as IL-4,/, mice were found to have higher parasite burdens when compared with wild-type mice. The goal of this study was to investigate the role of IL-4 in immunity to M. corti, focusing on the immunological profile and on potential mediators of pathology. IL-4,/, mice infected with M. corti showed 100% mortality by 32 days, whereas wild-type mice survived for approximately 1 year. Parasite burdens were significantly increased in the liver, peritoneal, and thoracic cavities of IL-4,/, mice, associated with impaired recruitment of inflammatory cells and a reduction in monocytes and macrophages. IL-5 production by splenocytes and expression in liver tissue was decreased in infected IL-4,/, mice compared with wild-type mice. In contrast, IL-4,/, mice produced increased amounts of IFN, and TNF,. Alternatively activated macrophages were a major feature of liver granulomas in wild-type mice evidenced by Arginase I expression, while livers from infected IL-4,/, mice showed impaired alternative macrophage activation without increased classical macrophage activation. Thus, lethality during M. corti infection of IL-4,/, mice is associated with decreased Th2 cytokines, increased Th1 cytokines and impairment of alternatively activated macrophages. [source] Life history correlates of oxidative damage in a free-living mammal populationFUNCTIONAL ECOLOGY, Issue 4 2009Daniel H. Nussey Summary 1Reactive oxygen species, produced as a by-product of normal metabolism, can cause intracellular damage and negatively impact on cell function. Such oxidative damage has been proposed as an evolutionarily important cost of growth and reproduction and as a mechanistic explanation for organismal senescence, although few tests of these ideas have occurred outside the laboratory. 2Here, we examined correlations between a measure of phospholipid oxidative damage in plasma samples and age, growth rates, parasite burden and investment in reproduction in a population of wild Soay sheep on St. Kilda, Scotland. 3We found that, amongst females of different ages, lambs had significantly elevated levels of oxidative damage compared to all other age classes and there was no evidence of increasing damage with age amongst adult sheep. 4Amongst lambs, levels of oxidative damage increased significantly with increasing growth rates over the first 4 months of life. Neither mean damage nor the effect of growth rate on damage differed between male and female lambs. 5Amongst adult female sheep, there was no evidence that body mass, current parasite burden or metrics of recent and past reproductive effort significantly predicted oxidative damage levels. 6This study is the first to examine age variation in an assay of oxidative damage and correlations between oxidative damage, growth and reproduction in a wild mammal. Our results suggest strong links between early conditions and oxidative damage in lambs, but also serve to highlight the limitations of cross-sectional data for studies examining associations between oxidative stress, ageing and life history in free-living populations. [source] Sex and age influence intestinal parasite burden in three boreal grouse speciesJOURNAL OF AVIAN BIOLOGY, Issue 5 2006Marja Isomursu Parasite infections are often more common in male vertebrates than in females. Sexual selection leading to dimorphism can cause sexual differences in immune defence, behaviour or body size. Possible proximate explanations for male bias in parasitism are the immunosuppressive effect of male sex hormones and the large body size of males which increases the likelihood of being parasitized. To evaluate these hypotheses, we studied the prevalence and abundance of intestinal helminth parasites in three boreal grouse species, the capercaillie Tetrao urogallus, the black grouse Tetrao tetrix, and the hazel grouse Bonasa bonasia. The first two are sexually dimorphic polygynous species while the latter species is sexually monomorphic and monogamous. We found a male-bias in the prevalence and abundance of the nematode Ascaridia compar. The bias was most pronounced in the polygynous black grouse and capercaillie. In the monogamous hazel grouse, there was a slight male-bias in occurrence of ascarids, but no bias in abundance. In juvenile grouse, the male-bias was larger than in adult grouse. No sexual bias was found in regard to the cestodes (Skrjabinia cesticillus, Paroniella urogalli and Hymenolepis spp.). However, age was a factor in cestode prevalence: juvenile grouse were more commonly infected than adults. Differences in growth rates and body size are potential factors that may lead to male-biased parasitism in these grouse species, and their impact requires further studies. [source] Dispersion patterns of parasites in 0+ year three-spined sticklebacks: a cross population comparisonJOURNAL OF FISH BIOLOGY, Issue 6 2002M. Kalbe Two ciliates and 16 metazoan parasites were identified in 434 0+ year three-spined sticklebacks Gasterosteus aculeatus collected from two small rivers and four lakes located in Schleswig-Holstein, Germany. By repeated sampling and analysis of dispersion patterns of six frequently occurring parasites no consistent evidence was found for mortality induced by a single parasite species. Linear log-variance to log-mean abundance ratios with slopes of c. 2 indicated negative binomial distributions for five of the six parasites. The numbers of these six parasites were combined as multiples of S.D. of each parasite species over all samples to form an ,individual parasitation index' (IPI), which showed that only in one locality a slight decrease in parasite burden occurred between September and April. In two of the lake populations, however, there was a distinct decline in the degree of dispersion in spring samples. This indicates that a combination of different species might cause parasite-induced host mortality, undetectable by patterns obtained from single species. There were differences in parasite diversity and intensity of infection among river compared to lake populations suggesting a role for parasites as selective agents in the ecological divergence of three-spined sticklebacks. [source] The relationship between flesh quality and numbers of Kudoa thyrsites plasmodia and spores in farmed Atlantic salmon, Salmo salar L.JOURNAL OF FISH DISEASES, Issue 8 2003J A Dawson-Coates Abstract Atlantic salmon, Salmo salar L., were exposed to Kudoa thyrsites (Myxozoa, Myxosporea)-containing sea water for 15 months, and then harvested and assessed for parasite burden and fillet quality. At harvest, parasites were enumerated in muscle samples from a variety of somatic and opercular sites, and mean counts were determined for each fish. After 6 days storage at 4 °C, fillet quality was determined by visual assessment and by analysis of muscle firmness using a texture analyzer. Fillet quality could best be predicted by determining mean parasite numbers and spore counts in all eight tissue samples (somatic and opercular) or in four fillet samples, as the counts from opercular samples alone showed greater variability and thus decreased reliability. The variability in both plasmodia and spore numbers between tissue samples taken from an individual fish indicated that the parasites were not uniformly distributed in the somatic musculature. Therefore, to best predict the probable level of fillet degradation caused by K. thyrsites infections, multiple samples must be taken from each fish. If this is performed, a mean plasmodia count of 0.3 mm,2 or a mean spore count of 4.0 × 105 g,1 of tissue are the levels where the probability of severe myoliquefaction becomes a significant risk. [source] Cellular responses and cytokine profiles in Ascaris lumbricoides and Trichuris trichiura infected patientsPARASITE IMMUNOLOGY, Issue 11-12 2002Stefan M. Geiger SUMMARY The impact of intestinal helminth infection, i.e. Ascaris lumbricoides and Trichuris trichiura, on cellular responsiveness and cytokine production was investigated in young adults. Ascaris -specific cellular responsiveness was higher in parasite-free endemic controls than in patients infected with T. trichiura, or A. lumbricoides, or patients co-infected with both parasites. Also, mitogen-induced tumour necrosis factor (TNF)-,, interleukin (IL)-12 and interferon (IFN)-, secretion by peripheral blood mononuclear cells (PBMC) was higher in negative endemic controls than in infected individuals. Ascaris antigen-specific production of TNF-,, IL-12 and IFN-, was low in singly Ascaris as well as in co-infected patients, whereas secretion of IL-10 and IL-13 was elevated and similarly high in all patient groups. The detection of Trichuris -specific and Ascaris -specific IgG4 revealed significantly higher serum antibody levels in Trichuris or Ascaris patients when compared to endemic controls (P < 0·05), whereas parasite-specific IgE antibody levels were similarly high in infected individuals and in endemic controls. In summary, chronically infected Ascaris and Trichuris patients with a high parasite load presented reduced cellular reactivity and lower type 1 TNF-,, IFN-, and IL-12 responses when compared with endemic controls, whereas type 2 IL-10 and IL-13 productions were similar in all groups from the endemic area. The former may support parasite persistence, whereas substantial type 2 cytokine release may promote protective immunity, suggesting an adaptation of the host to control the parasite burden while minimizing immune-mediated host self-damage. [source] A new standard for the assessment of disease progression in murine cutaneous leishmaniasisPARASITE IMMUNOLOGY, Issue 5 2000Lynden J.roberts Infection of mice with Leishmania major has been used both as a model for the cutaneous disease in humans and as a model for the more general control and function of helper T cells in immunity. In both cases, disease patterns and disease progression have been assessed by two complementary methods, lesion size and parasite burden in the draining lymph nodes. We propose a much improved method for the graphical representation of lesion development which conveys more information with better accuracy. We also describe a polymerase chain reaction method for determining parasite burden, which is faster and allows the analysis of larger numbers of experimental animals than the current limiting dilution analysis. Moreover, these methods are equally applicable to other infectious diseases, an obvious one being schistosomiasis. [source] Do helminth parasites protect against atopy and allergic disease?CLINICAL & EXPERIMENTAL ALLERGY, Issue 1 2009C. Flohr Summary Allergic diseases are rare in areas with high helminth parasite exposure and common where helminth exposure is lacking or significantly reduced, such as urban areas of developing countries and industrialized nations. Studies suggest that helminths induce a systemic immuno-modulatory network, including regulatory T cells and anti-inflammatory IL-10, which might play a key role in the protection against the allergic phenotype. Here, we review the current cross-sectional, birth cohort, and intervention study evidence for a protective effect of helminth infection on allergy. There is increasing evidence for a causal relationship between helminth infection and reduced skin prick test responsiveness to allergens. Cross-sectional studies have shown a consistent negative relationship, and these results have been confirmed in several, although not all, intervention studies. The immunological basis for this protective effect is less clear. Recent studies do not support the mast-cell IgE saturation hypothesis, but suggest that protection is associated with IL-10 production. As for allergic disease, cross-sectional studies support a negative relationship between clinical asthma and infection with some helminth species, particularly hookworm, but more studies are required to draw conclusions for eczema and rhinitis. In addition, none of the few intervention studies to date have demonstrated an increase in clinical allergy after helminth treatment, and further studies are needed. Furthermore, we are only beginning to understand the host genetic factors that are potentially involved. A genetically predetermined T-helper type 2 cell-dominated cytokine milieu reduces parasite burden and may enhance host survival in an environment where helminth parasites are prevalent. Lack of parasite exposure in such hosts might lead to hypersensitivity to seemingly minor environmental allergen stimuli. Large birth cohort studies in helminth-endemic areas that use epidemiological, genetic, and immunological tools are required to further examine how helminth parasites affect the development of atopy and allergic disease. Intervention studies with hookworm in parasite-naïve allergic individuals are currently ongoing in the United Kingdom to test the above hypotheses further. [source] An evidence-based approach to equine parasite control: It ain't the 60s anymoreEQUINE VETERINARY EDUCATION, Issue 6 2010R. M. Kaplan Summary Most veterinarians continue to recommend anthelmintic treatment programmes for horses that derive from knowledge and concepts more than 40 years old. However, much has changed since these recommendations were first introduced and current approaches routinely fail to provide optimal or even adequate levels of parasite control. There are many reasons for this. Recent studies demonstrate that anthelmintic resistance in equine parasites is highly prevalent and multiple-drug resistance is common in some countries, but few veterinarians take this into account when making treatment decisions or when recommending rotation of anthelmintics. Furthermore, the current approach of treating all horses at frequent intervals was designed specifically to control the highly pathogenic large strongyle, Strongylus vulgaris. But this parasite is now quite uncommon in managed horses in most of the world. Presently, the cyathostomins (small strongyles) are the principal parasitic pathogens of mature horses. The biology and pathogenesis of cyathostomins and S. vulgaris are very different and therefore require an entirely different approach. Furthermore, it is known that parasites are highly over-dispersed in hosts, such that a small percentage of hosts harbour most of the parasites. The common practices of recommending the same treatment programme for all horses despite great differences in parasite burdens, recommending prophylactic treatment of all horses without indication of parasitic disease or knowing what species of parasites are infecting the horses, recommending use of drugs without knowledge of their efficacy and failing to perform diagnostic (faecal egg count) surveillance for estimating parasite burdens and determining treatment efficacy, are all incompatible with current standards of veterinary practice. Consequently, it is necessary that attitudes and approaches to parasite control in horses undergo a complete overhaul. This is best achieved by following an evidence-based approach that takes into account all of these issues and is based on science, not tradition. [source] Intradermal NKT cell activation during DNA priming in heterologous prime-boost vaccination enhances T cell responses and protection against LeishmaniaEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2008Blaise Dondji Abstract Heterologous prime-boost vaccination employing DNA-vaccinia virus (VACV) modality using the Leishmania homologue of receptors for activated C,kinase (LACK) (p36) antigen has been shown to elicit protective immunity against both murine cutaneous and visceral leishmaniasis. However, DNA priming is known to have limited efficacy; therefore in the current study the effect of NKT cell activation using ,-galactosyl-ceramide (,GalCer) during intradermal DNAp36 priming was examined. Vaccinated mice receiving ,GalCer,+ DNAp36 followed by a boost with VVp36 appeared to be resolving their lesions and had at ten- to 20-fold higher reductions in parasite burdens. NKT cell activation during ,GalCer,+ DNAp36 priming resulted in higher numbers of antigen-reactive effector CD4+ and CD8+ T cells producing granzyme and IFN-,, with lower levels of IL-10. Although immunodepletion studies indicate that both CD4 and CD8 T cells provide protection in the vaccinated mice, the contribution of CD4+ T cells was significantly increased in mice primed with DNAp36 together with ,GalCer. Notably 5,months after boosting, mice vaccinated with DNAp36,+ ,GalCer continued to show sustained and heightened T cell immune responses. Thus, heterologous prime-boost vaccination using ,GalCer during priming is highly protective against murine cutaneous leishmaniasis, resulting in the heightened activation and development of CD4 and CD8 T cells (effector and memory T cells). [source] Supplementary winter feeding of wild red deer Cervus elaphus in Europe and North America: justifications, feeding practice and effectivenessMAMMAL REVIEW, Issue 4 2004R. J. PUTMAN ABSTRACT 1.,Supplementary winter feeding of game animals, and particularly deer, is a common practice throughout northern (continental) Europe and parts of North America. Feeding is normally associated with maintaining high densities of animals for hunting, in terms of: (i) maintaining or increasing body weights and condition overwinter; (ii) improving reproductive performance and fertility; (iii) increasing overwinter survival; and (iv) reducing levels of damage caused to agriculture and forestry or the natural heritage. We consider the balance of evidence on the effectiveness of winter feeding of red deer Cervus elaphus in achieving these objectives. Where that evidence is equivocal, we attempt to reconcile apparent contradictions to evaluate the circumstances under which winter feeding may or may not be effective. 2.,In general, feeding of red deer on open range appears to have relatively little effect on body weights or fecundity. Effects on increasing antler size and quality are variable and seem to depend on the degree to which animals may be mineral limited on native range. Effects on survival are similarly ambiguous. It is apparent, however, that to be effective in reducing mortality, any supplementation is required early in the season and not simply when heavy mortalities are already being experienced. If provision of supplementary foods is delayed until animals are perceived already to be in poor condition, such feeding may have little effect. 3.,One of the primary goals of winter feeding in both Europe and the USA has become the prevention of environmental damage, particularly damage to commercial and native forests, while maintaining deer populations at densities suitable for hunting. Again, empirical evidence for effectiveness in this regard is inconclusive, with some studies showing a decrease in damage caused, some showing no effect and others showing a significant increase in local impact. 4.,There are equally a number of problems associated with the provision of supplementary feeds overwinter. Those animals which come to the feeding stations may develop a reliance on the food supplement provided, reducing intake of natural forages to near zero; where feed provided is less than 100% of daily requirement, such animals may regularly lose, rather than gain condition. Feed provision is also extremely uneven at such feeding stations; dominant stags displace younger stags and hinds from the feed provided until they have themselves finished feeding. Concentrations of high densities of animals around small feed-areas may also increase the risk of infection and lead to development of high parasite burdens. 5.,In an attempt to assess the current status and distribution of supplementary winter feeding in Scotland, a questionnaire was circulated to a number of individual across the country. Results of this survey are summarized and conclusions presented on the likely effectiveness of current feeding practices in achieving their aims. [source] IL-4,/, mice with lethal Mesocestoides corti infections , reduced Th2 cytokines and alternatively activated macrophagesPARASITE IMMUNOLOGY, Issue 12 2009A. E. O'CONNELL Summary Protection against Mesocestoides corti, a cestode that invades vital organs, is dependent on the production of IL-4, as IL-4,/, mice were found to have higher parasite burdens when compared with wild-type mice. The goal of this study was to investigate the role of IL-4 in immunity to M. corti, focusing on the immunological profile and on potential mediators of pathology. IL-4,/, mice infected with M. corti showed 100% mortality by 32 days, whereas wild-type mice survived for approximately 1 year. Parasite burdens were significantly increased in the liver, peritoneal, and thoracic cavities of IL-4,/, mice, associated with impaired recruitment of inflammatory cells and a reduction in monocytes and macrophages. IL-5 production by splenocytes and expression in liver tissue was decreased in infected IL-4,/, mice compared with wild-type mice. In contrast, IL-4,/, mice produced increased amounts of IFN, and TNF,. Alternatively activated macrophages were a major feature of liver granulomas in wild-type mice evidenced by Arginase I expression, while livers from infected IL-4,/, mice showed impaired alternative macrophage activation without increased classical macrophage activation. Thus, lethality during M. corti infection of IL-4,/, mice is associated with decreased Th2 cytokines, increased Th1 cytokines and impairment of alternatively activated macrophages. [source] Usefulness of PCR Strategies For Early Diagnosis of Chagas' Disease Reactivation and Treatment Follow-Up in Heart TransplantationAMERICAN JOURNAL OF TRANSPLANTATION, Issue 6 2007M. Diez Heart transplantation (HTx) is a useful therapy for end-stage Chaga, cardiomyopathy; however, Chagas reactivation remains a mayor complication. Parasitological methods offer poor diagnostic sensitivity, and use of more sensitive tools such as the Polymerase chain reaction (PCR) is usually necessary. In the present study, reactivation incidence and PCR usefulness for early reactivation diagnosis, as well as for treatment response evaluation during follow-up, were analyzed using Strout parasite detection test, in 10 of 222 consecutive HTx patients suffering Chagas cardiomyopathy. PCR strategies targeted to minicircle sequences (kDNA, detection limit 1 parasite/ 10 mL blood) and miniexon genes (SL-DNA, 200 parasite/10 mL) were performed to compare parasite burdens between samples. No patients received prophylactic antiprotozoal therapy (benznidazole). Five patients (50%) exhibited clinical reactivation within a mean period of 71.6 days; positive Strout results were observed in most cases presenting clinical manifestations. kDNA-PCR was positive 38,85 days before reactivation, whereas SLDNA-PCR became positive only 7,21 days later, revealing post-HTx parasitic load enhancement present prior to clinical reactivation development. Reactivations were successfully treated with benznidazole and generated negative PCR results. Results observed in this study indicate the value of PCR testing for an early diagnosis of Chagas reactivation as well as for monitoring treatment efficacy. [source] | ||||||||||||||||