Autoantibodies to iron-binding proteins in pigs infested with Sarcoptes scabiei
- Authors: Toet, Hayley , Fischer, Katja , Mounsey, Kate , Sandeman, Mark
- Date: 2014
- Type: Text , Journal article
- Relation: Veterinary Parasitology Vol. 205, no. 1-2 (2014), p. 263-270
- Full Text: false
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- Description: Despite the availability of effective treatments, Sarcoptes scabiei remains a major health problem in the pig industry. Unsuccessful control of the disease is often due to the lack of reliable detection methods, with current tests relying on skin scrapings and crude antigen ELISAs. A previous analysis of antigens in pig skin scrapings reported that anti-transferrin antibodies were present in S. scabiei infected animals and that this finding might be considered as a useful diagnostic tool. This paper confirms IgG autoantibodies against transferrin, including the first report of IgM autoantibodies, in both naturally and experimentally infected pigs using ELISA and dot blot assays. Autoantibodies were also detected in pigs to ferritin and to a lesser extent lactoferrin. Immunoblotting confirmed the presence of IgG and IgM autoantibodies in mange positive pigs, as well as IgM antibodies to transferrin and albumin in mange negative pigs. These findings suggest the presence of natural autoantibodies to transferrin and albumin in pigs. The development of the IgG autoimmune response may either be a host mechanism for limiting iron to the mite via antibody mediated clearance, the result of host exposure to mite iron-binding homologues or because of a mite-induced antigenic change to host transferrin. Further investigation into the formation of these autoantibodies may provide insights into the importance of iron in scabies infections and the development and perseverance of S. scabiei infections in pigs. The specificity and sensitivity of the anti-transferrin response reinforces its potential in the diagnosis of scabies in pigs. © 2014 Elsevier B.V.
Control of the sheep blowfly in Australia and New Zealand - are we there yet?
- Authors: Sandeman, Mark , Levot, Garry , Heath, Allen , James, Peter , Greeff, Johan , Scott, Max , Batterham, Philip , Bowles, Vern
- Date: 2014
- Type: Text , Journal article
- Relation: International Journal for Parasitology Vol. 44, no. 12 (2014), p. 879-891
- Full Text: false
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- Description: The last 50. years of research into infections in Australia and New Zealand caused by larvae of the sheep blowfly, Lucilia cuprina, have significantly advanced our understanding of this blowfly and its primary host, the sheep. However, apart from some highly effective drugs it could be argued that no new control methodologies have resulted. This review addresses the major areas of sheep blowfly research over this period describing the significant outcomes and analyses, and what is still required to produce new commercial control technologies. The use of drugs against this fly species has been very successful but resistance has developed to almost all current compounds. Integrated pest management is becoming basic to control, especially in the absence of mulesing, and has clearly benefited from computer-aided technologies. Biological control has more challenges but natural and perhaps transformed biopesticides offer possibilities for the future. Experimental vaccines have been developed but require further analysis of antigens and formulations to boost protection. Genetic technologies may provide potential for long-term control through more rapid indirect selection of sheep less prone to flystrike. Finally in the future, genetic analysis of the fly may allow suppression and perhaps eradication of blowfly populations or identification of new and more viable targets for drug and vaccine intervention. Clearly all these areas of research offer potential new controls but commercial development is perhaps inhibited by the success of current chemical insecticides and certainly requires a significant additional injection of resources.
Current status for gastrointestinal nematode diagnosis in small ruminants: where are we and where are we going?
- Authors: Preston, Sarah , Sandeman, Mark , Gonzalez, Jorge , Piedrafita, David
- Date: 2014
- Type: Text , Journal article
- Relation: Journal of immunology research Vol. 2014, no. September (2014), p. Article no. 210350
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- Description: Gastrointestinal nematode (GIN) parasites pose a significant economic burden particularly in small ruminant production systems. Anthelmintic resistance is a serious concern to the effective control of GIN parasites and has fuelled the focus to design and promote sustainable control of practices of parasite control. Many facets of sustainable GIN parasite control programs rely on the ability to diagnose infection both qualitatively and quantitatively. Diagnostics are required to determine anthelmintic efficacies, for targeted treatment programs and selection of animals for parasite resistant breeding. This review describes much of the research investigated to date to improve the current diagnostic for the above practices which is based on counting the number of parasite eggs in faeces.
Genetic resistance to growth of Lucilia cuprina larvae
- Authors: Smith, J. , Colditz, Ian , Piper, L. , Sandeman, Mark , Dominik, S.
- Date: 2008
- Type: Text , Journal article
- Relation: Animal Production Science Vol. 48, no. (2008), p. 1210-1216
- Full Text: false
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- Description: Cutaneous myiasis (fly strike), caused by Lucilia cuprina, is a major ectoparasitic infection of sheep. Previous research has identified contributions of body conformation, wool characteristics and resistance to bacterial dermatoses to resistance to fly strike. This paper investigates whether genetic variation occurs amongst sheep in growth of larvae on skin. Mixed sex Merino sheep in 27 half-sibling groups were challenged with freshly hatched Lucilia cuprina larvae, and survival and growth of larvae were measured after 50 h. Growth but not survival of larvae had moderate heritability (0.29 ± 0.22), comparable to that seen for resistance to nematode parasites in sheep. Phenotypic correlations between resistance to larval growth and wool traits, skin wheal response to intradermal injection of larval excretory secretory products and resistance to internal parasites were negligible; however, there was a significant negative phenotypic correlation with fleece rot score after exposure of sheep to simulated rain at a time independent to that of measurement of larval growth. Larval growth was negatively correlated with peripheral blood eosinophil numbers measured either before or after larval challenge. In addition, larval growth in vitro on serum collected from challenged sheep was moderately associated with larval growth in vivo. A search for quantitative trait loci (QTL) for larval survival and growth was conducted in data from 94 half-sibling progeny of a Merino × Romney sire backcrossed to Merino ewes. Potential QTL for larval growth were identified on chromosome 11 and for larval survival on chromosome 18, although phenotyping greater numbers of sheep and a higher marker density on these chromosomes is necessary to confirm the result. We conclude that this study has identified a novel level of resistance of Merino sheep to growth of L. cuprina larvae that may be mediated in part through actions of anti-larval factors in serum and eosinophils. Further studies are required to establish the impact of growth retardation on the severity of systemic responses of sheep to fly strike and on the biology of adult flies
Hc-daf-2 encodes an insulin-like receptor kinase in the barber's pole worm, Haemonchus contortus, and restores partial dauer regulation
- Authors: Li, Facai , Lok, James , Gasser, Robin , Korhonen, Pasi , Sandeman, Mark , Shi, Deshi , Zhou, Rui , Li, Xiangrui , Zhou, Yanqin , Zhao, Junlong , Hu, Min
- Date: 2014
- Type: Text , Journal article
- Relation: International Journal for Parasitology Vol. 44, no. 7 (2014), p. 485-496
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- Description: Infective L3s (iL3s) of parasitic nematodes share common behavioural, morphological and developmental characteristics with the developmentally arrested (dauer) larvae of the free-living nematode Caenorhabditis elegans. It is proposed that similar molecular mechanisms regulate entry into or exit from the dauer stage in C. elegans, and the transition from free-living to parasitic forms of parasitic nematodes. In C. elegans, one of the key factors regulating the dauer transition is the insulin-like receptor (designated Ce-DAF-2) encoded by the gene Ce-daf-2. However, nothing is known about DAF-2 homologues in most parasitic nematodes. Here, using a PCR-based approach, we identified and characterised a gene (Hc-daf-2) and its inferred product (Hc-DAF-2) in Haemonchus contortus (a socioeconomically important parasitic nematode of ruminants). The sequence of Hc-DAF-2 displays significant sequence homology to insulin receptors (IR) in both vertebrates and invertebrates, and contains conserved structural domains. A sequence encoding an important proteolytic motif (RKRR) identified in the predicted peptide sequence of Hc-DAF-2 is consistent with that of the human IR, suggesting that it is involved in the formation of the IR complex. The Hc-daf-2 gene was transcribed in all life stages of H. contortus, with a significant up-regulation in the iL3 compared with other stages. To compare patterns of expression between Hc-daf-2 and Ce-daf-2, reporter constructs fusing the Ce-daf-2 or Hc-daf-2 promoter to sequence encoding GFP were microinjected into the N2 strain of C. elegans, and transgenic lines were established and examined. Both genes showed similar patterns of expression in amphidial (head) neurons, which relate to sensation and signal transduction. Further study by heterologous genetic complementation in a daf-2-deficient strain of C. elegans (CB1370) showed partial rescue of function by Hc-daf-2. Taken together, these findings provide a first insight into the roles of Hc-daf-2/. Hc-DAF-2 in the biology and development of H. contortus, particularly in the transition to parasitism. © 2014 Australian Society for Parasitology Inc.
Prevalence of infestation with gastrointestinal nematodes in Pony Club horses in Victoria
- Authors: Flanagan, Katie , Morton, J. , Sandeman, Mark
- Date: 2013
- Type: Text , Journal article
- Relation: Australian Veterinary Journal Vol. 91, no. 6 (2013), p. 241-245
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- Description: Background The aims of the present study were to identify the common gastrointestinal nematodes, to assess the prevalence of infestation with gastrointestinal nematodes, and to assess some potential indirect determinants of nematode parasitism in Victorian Pony Club horses. Methods A total of 106 horses from five Pony Clubs from outer Melbourne and Geelong, Victoria, Australia, were enrolled in a cross-sectional study. Fresh faecal samples were collected and faecal egg counts (FECs) performed on site within 2 h of collection. Potential determinants of the FEC were analysed using logistic and negative binomial regression. Results FECs ranged from 0 to 3750 eggs per gram (epg), with an average of 422 epg. Eggs were detected in the faeces of 52% of horses (55/106) and the average count was 813 epg. Counts were 500 epg or greater in 27% (29/106) of horses. Pony Club, season and sex of the horse were not associated with the FEC. Among horses treated with anthelmintics 8 weeks or less prior to sampling, FECs were commonly ≥50 epg, and high FECs were relatively common. Conclusions The results indicate that treatment efficacy is commonly low and/or rapid re-infection after treatment is common, and show that management practices for internal parasite control are often inadequate for preventing high FECs among Pony Club horses in Victoria.
The composition and stability of the faecal microbiota of merino sheep
- Authors: Mamun, Mohammed , Sandeman, Mark , Rayment, Philip , Brook-Carter, Phillip , Scholes, Emily , Kasinadhuni, Naga , Piedrafita, David , Greenhill, Andrew
- Date: 2020
- Type: Text , Journal article
- Relation: Journal of Applied Microbiology Vol. 128, no. 1 (2020), p. 280-291
- Full Text: false
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- Description: Aims: To determine the composition and temporal stability of the gut (faecal) microbiota of sheep (Ovis aries). Methods and Results: Microbial population dynamics was conducted using ARISA (28 sheep) and 16S rRNA sequencing (11 sheep). Firmicutes and Bacteroidetes were the predominant bacterial phyla, constituting ~80% of the total population. The core faecal bacterial microbiota of sheep consisted of 67 of 136 detected families and 91 of 215 detected species. Predominant microbial taxa included Ruminococcaceae, unassigned families in Bacteroidales and Clostridiales, Verrucomicrobiaceae and Paraprevotellaceae. Diversity indices and core microbiota composition demonstrated the stability of the core microbiota over 2–4 weeks. The core microbiota remained similar over ~5 months. Conclusions: Temporal stability of the sheep microbiota is high over 2–4 weeks in the absence of experimental variables. The core microbiota of Merino sheep shares taxa found in other breeds of sheep and other ruminants. Significance and Impact of the Study: Numerous studies seek to investigate the impact of experimental variables on gut microbiota composition. To do so, knowledge of the innate stability (or instability) of the microbiota over an experimental time course is required, independent of other variables. We have demonstrated high stability of the gut microbiota in sheep over 3–4 weeks, with moderate stability over ~5 months. © 2019 The Society for Applied Microbiology
The current status of anthelmintic resistance in a temperate region of Australia; implications for small ruminant farm management
- Authors: Preston, Sarah , Piedrafita, David , Sandeman, Mark , Cotton, Steve
- Date: 2019
- Type: Text , Journal article
- Relation: Veterinary Parasitology: Regional Studies and Reports Vol. 17, no. (2019), p.
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- Description: Widespread anthelmintic resistance in small ruminants is a constraint on the profitability of the meat/wool industry. Limited published data is available on the prevalence and efficacy of anthelmintics, particularly in Australia where parasites affecting ruminant systems vary greatly between geographic regions. This paper reports on the anthelmintic resistance status in a temperate region of Victoria, Australia, a major sheep producing state largely affected by Trichostrongylus species and Teladorsagia circumcincta. The prevalence of anthelmintic resistance to any product was high (71%), with farms reporting varying levels of drug efficacies (21–100%). Resistance to older chemical groups (i.e. fenbendazole and levamisole) and single active macrocyclic lactone treatments was higher than newer chemical groups and combination treatments. This report provides clarity on anthelmintic resistance in the temperate region of Victoria and more importantly suggests that more comprehensive, regional specific anthelmintic resistance studies are required to understand the real level of chemical resistance threatening the effective control of worms. © 2019
The immunobiology of myiasis infections--whatever happened to vaccination?
- Authors: Sandeman, Mark , Bowles, Vern , Colwell, Doug
- Date: 2014
- Type: Text , Journal article
- Relation: Parasite immunology Vol. 36, no. 11 (2014), p. 605-615
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- Description: The current state of myiasis vaccine technologies are reviewed mainly in the primary research genera of Lucilia and Hypoderma. The importance of myiasis flies as primary causes of morbidity and mortality in agricultural species and man has not diminished despite the existence of good control strategies. However, the development of vaccines against myiasis infections has been relatively quiescent for more than 10 years despite the rapid development of genomic and proteomic analysis and of skills in data interpretation. The value of vaccine research in an era of chemical primacy is analysed. In fact, recent findings of drug resistance and the impact of animal welfare concerns should mean a renewed interest in alternative controls. The reasons that this has not been true to date are explored and new possibilities discussed.
The use of detector dogs in the diagnosis of nematode infections in sheep feces
- Authors: Richards, Kate , Cotton, Stephen , Sandeman, Mark
- Date: 2008
- Type: Text , Journal article
- Relation: Journal of Veterinary Behavior: Clinical Applications and Research Vol. 3, no. 1 (2008), p. 25-31
- Full Text: false
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- Description: This study was conducted to assess a dog's ability to differentiate between nematode-infected and uninfected sheep feces. Two German shepherd bitches were trained for scent detection over a 6-month period using operant/clicker conditioning. On completion of the training, testing was undertaken with 9 paper bags containing uninfected and 1 with infected feces, placed randomly around a circle. The dog and handler were not able to observe the placement of the bags. The 10th bag contained feces from sheep infected with either Teladorsagia circumcincta, Trichostrongylus vitrinus, Haemonchus contortus, or a mixed infection of all 3 species. Over 80 trials the dog had a mean success rate of greater than 80% in the detection of T. circumcincta- or T. vitrinus-infected feces and H. contortus-infected feces was detected with a slightly lower reliability of 76%, but mixed infections were detected at 92% reliability (one-proportion binomial analysis, P < 0.05). Trials were then undertaken to determine the time after administration of infective larvae that the dog was first able to differentiate T. circumcincta infection in sheep feces. At 7 days postinfection (dpi), the dog was capable of identifying T. circumcincta at least 85% of the time. These trials demonstrate that dogs are able to detect the common parasite infections in sheep with reliability equal to immunological assays. The results suggest that diagnostics based on odor detection using dogs to identify signature odors which could then be used to create sensitive detection devices might allow parasite detection on-farm and on all sheep in a flock.