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Shanebeck KM, Besson AA, Lagrue C, Green SJ. The energetic costs of sub-lethal helminth parasites in mammals: a meta-analysis. Biol Rev Camb Philos Soc 2022; 97:1886-1907. [PMID: 35678252 DOI: 10.1111/brv.12867] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 05/02/2022] [Accepted: 05/05/2022] [Indexed: 01/07/2023]
Abstract
Parasites, by definition, have a negative effect on their host. However, in wild mammal health and conservation research, sub-lethal infections are commonly assumed to have negligible health effects unless parasites are present in overwhelming numbers. Here, we propose a definition for host health in mammals that includes sub-lethal effects of parasites on the host's capacity to adapt to the environment and maintain homeostasis. We synthesized the growing number of studies on helminth parasites in mammals to assess evidence for the relative magnitude of sub-lethal effects of infection across mammal taxa based on this expanded definition. Specifically, we develop and apply a framework for organizing disparate metrics of parasite effects on host health and body condition according to their impact on an animal's energetic condition, defined as the energetic burden of pathogens on host physiological and behavioural functions that relate directly to fitness. Applying this framework within a global meta-analysis of helminth parasites in wild, laboratory and domestic mammal hosts produced 142 peer-reviewed studies documenting 599 infection-condition effects. Analysing these data within a multiple working hypotheses framework allowed us to evaluate the relative weighted contribution of methodological (study design, sampling protocol, parasite quantification methods) and biological (phylogenetic relationships and host/parasite life history) moderators to variation in the magnitude of health effects. We found consistently strong negative effects of infection on host energetic condition across taxonomic groups, with unusually low heterogeneity in effect sizes when compared with other ecological meta-analyses. Observed effect size was significantly lower within cross-sectional studies (i.e. observational studies that investigated a sub-set of a population at a single point in time), the most prevalent methodology. Furthermore, opportunistic sampling led to a weaker negative effect compared to proactive sampling. In the model of host taxonomic group, the effect of infection on energetic condition in carnivores was not significant. However, when sampling method was included, it explained substantial inter-study variance; proactive sampling showing a strongly significant negative effect while opportunistic sampling detected only a weak, non-significant effect. This may partly underlie previous assumptions that sub-lethal parasites do not have significant effects on host health. We recommend future studies adopt energetic condition as the framework for assessing parasite effects on wildlife health and provide guidelines for the selection of research protocols, health proxies, and relating infection to fitness.
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Affiliation(s)
- Kyle M Shanebeck
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, Alberta, Canada
| | - Anne A Besson
- Department of Zoology, University of Otago, 340 Great King Street, Dunedin, 9016, New Zealand
| | - Clement Lagrue
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, Alberta, Canada.,Department of Zoology, University of Otago, 340 Great King Street, Dunedin, 9016, New Zealand.,Department of Conservation, 265 Princes Street, Dunedin, 9016, New Zealand
| | - Stephanie J Green
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, Alberta, Canada
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Wilson CS, Jenkins DJ, Brookes VJ, Barnes TS. An eight-year retrospective study of hydatid disease (Echinococcus granulosus sensu stricto) in beef cattle slaughtered at an Australian abattoir. Prev Vet Med 2019; 173:104806. [PMID: 31704561 DOI: 10.1016/j.prevetmed.2019.104806] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 10/09/2019] [Accepted: 10/11/2019] [Indexed: 10/25/2022]
Abstract
A retrospective study was conducted on 1,178,329 cattle slaughtered at an eastern Australian abattoir between 2010 and 2018. The data were searched for records in which a diagnosis of hydatid disease was made by routine meat inspection and apparent prevalence was calculated. True prevalence of hydatid disease in any organ was then estimated using previously reported sensitivity and specificity for diagnosis of hepatic hydatid disease by routine meat inspection. Mixed effects logistic regression was conducted to assess putative associations between dentition (age), sex, and feed-type (grass- or grain-fed), and hydatid disease reported at slaughter, with origin (Property Identification Code [PIC] region) included as a random effect. Regression was also conducted on subsets stratified by dentition and feed-type to account for measurement bias resulting from differences in sensitivity and specificity between groups of cattle. Discrete-Poisson models (SaTScan, v.9.5) were used to detect spatio-temporal clustering of hydatid-positive cattle within PIC regions. The apparent prevalence of hydatid disease reported in any organ was 8.8% (n = 104,038; 95% confidence interval [CI] 8.8-8.9%). The liver, lungs, heart, spleen, and kidneys were reported infected with hydatid cysts. Of cattle reported infected with hydatid cysts, 75.6% had both the liver and lungs reported infected. True prevalence was estimated to be 33.0% (95% CI 24.4-44.4%). Significant interaction between dentition and feed-type was identified. Risk of reported hydatid disease was highest in both eight-tooth grass- and eight-tooth grain-fed cattle (OR 17.5, 95% CI 17.0-18.1, reference level [ref] zero-tooth; OR 4.8, 95% CI 4.4-5.2, ref zero-tooth, respectively). Sex was also significantly associated with reported cases of hydatid disease at slaughter, with the highest odds in females (two-tooth group, OR 1.2, 95% CI 1.1-1.2, ref male). Three spatio-temporal clusters of hydatid-positive regions were identified. The most likely cluster was located in north eastern New South Wales from June 2012 to September 2015 (log likelihood ratio 4774, P < 0.001). This study indicates a higher prevalence of hydatid disease than previously recognised and demonstrates that an effect of sex cannot be ruled out. The identification of clusters could indicate periods when hosts of Echinococcus were more abundant, or localised climatic events that facilitated transmission to cattle. Given the high prevalence, the financial impact of hydatid disease on the Australian beef industry and risk factors associated with variation in spatial distribution should be determined to target interventions.
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Affiliation(s)
- Cara S Wilson
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW 2678, Australia; Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW 2650, Australia.
| | - David J Jenkins
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW 2678, Australia; Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW 2650, Australia
| | - Victoria J Brookes
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW 2678, Australia; Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW 2650, Australia
| | - Tamsin S Barnes
- The University of Queensland, School of Veterinary Science, Gatton, QLD 4343, Australia; The University of Queensland, Queensland Alliance for Agriculture and Food Innovation, Gatton, QLD 4343, Australia
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Wilson CS, Brookes VJ, Barnes TS, Woodgate RG, Peters A, Jenkins DJ. Revisiting cyst burden and risk factors for hepatic hydatid disease (Echinococcus granulosus sensu stricto) in Australian beef cattle. Prev Vet Med 2019; 172:104791. [PMID: 31627165 DOI: 10.1016/j.prevetmed.2019.104791] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 08/07/2019] [Accepted: 10/02/2019] [Indexed: 10/25/2022]
Abstract
The characteristics and risk factors associated with hepatic Echinococcus granulosus sensu stricto infection (hydatid disease) were investigated in beef cattle slaughtered at an abattoir in eastern Australia. Sampled cattle were sourced from all eastern states, predominantly from regions associated with the Great Dividing Range. Livers and corresponding demographic data were collected from 601 carcasses. Livers were examined for the number, size, viability, and fertility of hydatid cysts. Mixed effects logistic regression was used to evaluate associations of sex, feed-type (grass- or grain-fed), and dentition (age) on hydatid disease. Hydatid cysts were detected in all dentition groups. The most commonly sampled dentition group was zero-tooth cattle (less than 18 months). Twenty-nine percent of infected livers had only one cyst, and 48% of infected livers contained viable cysts. Thirty-seven percent of infected livers had cysts that were 3-10 mm in diameter. The size and number of cysts were positively correlated with age of the animal. Regression analysis showed that the odds of hydatid disease were highest in eight-tooth cattle (>42 months; OR 26.9; 95% CI 11.8-61.6; reference level [ref] zero-tooth). Being grass-fed was also significantly associated with the presence of hydatid disease (total effect; OR 3.0; 95% CI 1.7-5.5; ref grain-fed). Although there was no evidence of a total effect of sex across the study population, males of a given dentition group and feed-type (grass- or grain-fed) were more likely to be infected than respective females. Despite changes in Australian agriculture in the last 30 years, the burden (number, size, and viability of cysts) of hydatid disease in individual infected animals remains similar to previous Australian studies.
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Affiliation(s)
- Cara S Wilson
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW 2678, Australia; Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW 2650, Australia.
| | - Victoria J Brookes
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW 2678, Australia; Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW 2650, Australia; Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, NSW 2570, Australia
| | - Tamsin S Barnes
- The University of Queensland, School of Veterinary Science, Gatton, QLD 4343, Australia; The University of Queensland, Queensland Alliance for Agriculture and Food Innovation, Gatton, QLD 4343, Australia
| | - Rob G Woodgate
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW 2678, Australia; Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW 2650, Australia
| | - Andrew Peters
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW 2678, Australia; Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW 2650, Australia
| | - David J Jenkins
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW 2678, Australia; Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW 2650, Australia
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Romig T, Deplazes P, Jenkins D, Giraudoux P, Massolo A, Craig PS, Wassermann M, Takahashi K, de la Rue M. Ecology and Life Cycle Patterns of Echinococcus Species. ADVANCES IN PARASITOLOGY 2017; 95:213-314. [PMID: 28131364 DOI: 10.1016/bs.apar.2016.11.002] [Citation(s) in RCA: 252] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The genus Echinococcus is composed of eight generally recognized species and one genotypic cluster (Echinococcus canadensis cluster) that may in future be resolved into one to three species. For each species, we review existing information on transmission routes and life cycles in different geographical contexts and - where available - include basic biological information of parasites and hosts (e.g., susceptibility of host species). While some Echinococcus spp. are transmitted in life cycles that involve predominantly domestic animals (e.g., dog - livestock cycles), others are wildlife parasites that do or do not interact with domestic transmission. In many cases, life cycle patterns of the same parasite species differ according to geography. Simple life cycles contrast with transmission patterns that are highly complex, involving multihost systems that may include both domestic and wild mammals. Wildlife transmission may be primary or secondary, i.e., resulting from spillovers from domestic animals. For most of the species and regions, existing information does not yet permit a conclusive description of transmission systems. Such data, however, would be highly relevant, e.g., for anticipation of geographical changes of the presence and frequency of these parasites in a warming world, or for initiating evidence-based control strategies.
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Affiliation(s)
- T Romig
- University of Hohenheim, Stuttgart, Germany
| | - P Deplazes
- University of Zürich, Zurich, Switzerland
| | - D Jenkins
- Charles Sturt University, Wagga Wagga, NSW, Australia
| | - P Giraudoux
- University of Franche-Comté and Institut Universitaire de France, Besancon, France
| | - A Massolo
- University of Calgary, Calgary, Alberta, Canada
| | - P S Craig
- University of Salford, Greater Manchester, United Kingdom
| | | | | | - M de la Rue
- University of Santa Maria, Santa Maria RS, Brazil
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Fleming PJS, Ballard G, Reid NCH, Tracey JP. Invasive species and their impacts on agri-ecosystems: issues and solutions for restoring ecosystem processes. RANGELAND JOURNAL 2017. [DOI: 10.1071/rj17046] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Humans are the most invasive of vertebrates and they have taken many plants and animals with them to colonise new environments. This has been particularly so in Australasia, where Laurasian and domesticated taxa have collided with ancient Gondwanan ecosystems isolated since the Eocene Epoch. Many plants and animals that humans introduced benefited from their pre-adaptation to their new environments and some became invasive, damaging the biodiversity and agricultural value of the invaded ecosystems. The invasion of non-native organisms is accelerating with human population growth and globalisation. Expansion of trade has seen increases in purposeful and accidental introductions, and their negative impacts are regarded as second only to activities associated with human population growth. Here, the theoretical processes, economic and environmental costs of invasive alien species (i.e. weeds and vertebrate pests) are outlined. However, defining the problem is only one side of the coin. We review some theoretical underpinnings of invasive species science and management, and discuss hypotheses to explain successful biological invasions. We consider desired restoration states and outline a practical working framework for managing invasive plants and animals to restore, regenerate and revegetate invaded Australasian ecosystems.
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Rogan MT, Bodell AJ, Craig PS. Post-encystment/established immunity in cystic echinococcosis: is it really that simple? Parasite Immunol 2014; 37:1-9. [DOI: 10.1111/pim.12149] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 09/29/2014] [Indexed: 11/30/2022]
Affiliation(s)
- M. T. Rogan
- Cestode Zoonoses Research Group; School of Environment and Life Sciences; University of Salford; Salford M54WT UK
| | - A. J. Bodell
- Cestode Zoonoses Research Group; School of Environment and Life Sciences; University of Salford; Salford M54WT UK
| | - P. S. Craig
- Cestode Zoonoses Research Group; School of Environment and Life Sciences; University of Salford; Salford M54WT UK
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Echinococcus as a model system: biology and epidemiology. Int J Parasitol 2014; 44:865-77. [DOI: 10.1016/j.ijpara.2014.07.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 07/19/2014] [Accepted: 07/21/2014] [Indexed: 12/22/2022]
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Atkinson JAM, Williams GM, Yakob L, Clements ACA, Barnes TS, McManus DP, Yang YR, Gray DJ. Synthesising 30 years of mathematical modelling of Echinococcus transmission. PLoS Negl Trop Dis 2013; 7:e2386. [PMID: 24009786 PMCID: PMC3757076 DOI: 10.1371/journal.pntd.0002386] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 07/15/2013] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Echinococcosis is a complex zoonosis that has domestic and sylvatic lifecycles, and a range of different intermediate and definitive host species. The complexities of its transmission and the sparse evidence on the effectiveness of control strategies in diverse settings provide significant challenges for the design of effective public health policy against this disease. Mathematical modelling is a useful tool for simulating control packages under locally specific transmission conditions to inform optimal timing and frequency of phased interventions for cost-effective control of echinococcosis. The aims of this review of 30 years of Echinococcus modelling were to discern the epidemiological mechanisms underpinning models of Echinococcus granulosus and E. multilocularis transmission and to establish the need to include a human transmission component in such models. METHODOLOGY/PRINCIPAL FINDINGS A search was conducted of all relevant articles published up until July 2012, identified from the PubMED, Web of Knowledge and Medline databases and review of bibliographies of selected papers. Papers eligible for inclusion were those describing the design of a new model, or modification of an existing mathematical model of E. granulosus or E. multilocularis transmission. A total of 13 eligible papers were identified, five of which described mathematical models of E. granulosus and eight that described E. multilocularis transmission. These models varied primarily on the basis of six key mechanisms that all have the capacity to modulate model dynamics, qualitatively affecting projections. These are: 1) the inclusion of a 'latent' class and/or time delay from host exposure to infectiousness; 2) an age structure for animal hosts; 3) the presence of density-dependent constraints; 4) accounting for seasonality; 5) stochastic parameters; and 6) inclusion of spatial and risk structures. CONCLUSIONS/SIGNIFICANCE This review discusses the conditions under which these mechanisms may be important for inclusion in models of Echinococcus transmission and proposes recommendations for the design of dynamic human models of transmission. Accounting for the dynamic behaviour of the Echinococcus parasites in humans will be key to predicting changes in the disease burden over time and to simulate control strategies that optimise public health impact.
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Affiliation(s)
- Jo-An M Atkinson
- School of Population Health, Infectious Disease Epidemiology Unit, University of Queensland, Brisbane, Australia.
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Abstract
Marsupial immune responses were previously touted as ‘primitive’ but we now know that the marsupial immune system is complex and on par with that of eutherian mammals. In this manuscript we review the field of marsupial immunology, focusing on basic anatomy, developmental immunology, immunogenetics and evolution. We concentrate on advances to our understanding of marsupial immune gene architecture, made possible by the recent sequencing of the opossum, tammar wallaby and Tasmanian devil genomes. Characterisation of immune gene sequences now paves the way for the development of immunological assays that will allow us to more accurately study health and disease in marsupials.
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Barnes T, Deplazes P, Gottstein B, Jenkins D, Mathis A, Siles-Lucas M, Torgerson P, Ziadinov I, Heath D. Challenges for diagnosis and control of cystic hydatid disease. Acta Trop 2012; 123:1-7. [PMID: 22410539 DOI: 10.1016/j.actatropica.2012.02.066] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2011] [Revised: 02/14/2012] [Accepted: 02/26/2012] [Indexed: 12/12/2022]
Abstract
This paper is based on the experience of the authors, with the aim to define the challenges for Echinococcus granulosus (E.g./CE) diagnosis and control for those countries that may now or in the future be contemplating control of hydatid disease. A variety of methods are available for diagnosis in humans but a universal gold standard is lacking. Diagnosis in definitive hosts can avoid necropsy by the use of methods such as coproantigen detection but test performance is variable between populations. A sylvatic cycle adds challenges in some countries and the epidemiology of the parasite in these hosts is poorly understood. Control by solely administering praziquantel to dogs is not effective in developing countries where the disease is endemic. Additional avenues to pursue include the instigation of participatory planning, use of an existing vaccination for intermediate hosts and development of a vaccine and long-acting anthelmitic implants for definitive hosts. Promoting public acceptance of control of the dog population by humane euthanasia and reduced reproduction is also essential.
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Molecular epidemiology of Echinococcosis from food producing animals in north India. Vet Parasitol 2012; 186:503-6. [DOI: 10.1016/j.vetpar.2011.11.064] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 11/16/2011] [Accepted: 11/18/2011] [Indexed: 11/18/2022]
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12
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Abdybekova A, Torgerson P. Frequency distributions of helminths of wolves in Kazakhstan. Vet Parasitol 2012; 184:348-51. [DOI: 10.1016/j.vetpar.2011.09.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2011] [Revised: 09/01/2011] [Accepted: 09/06/2011] [Indexed: 11/24/2022]
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Barnes T, Hinds L, Jenkins D, Bielefeldt-Ohmann H, Lightowlers M, Coleman G. Comparative Pathology of Pulmonary Hydatid Cysts in Macropods and Sheep. J Comp Pathol 2011; 144:113-22. [DOI: 10.1016/j.jcpa.2010.07.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 05/17/2010] [Accepted: 07/22/2010] [Indexed: 01/01/2023]
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Young LJ, Harrison GA. Molecular characterization of interleukin-1Beta in the tammar wallaby (Macropus eugenii). J Vet Med Sci 2010; 72:1521-6. [PMID: 20628231 DOI: 10.1292/jvms.10-0100] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Interleukin-1beta (IL-1β) plays a significant role in the onset and pathogenesis of inflammation in mammalian hosts. Although well characterized in a range of vertebrate species, little is known about this important cytokine in marsupial mammals. We report here the molecular cloning and characterization of IL-1β in the tammar wallaby (Macropus eugenii). M. eugenii IL-1β has an open-reading frame of 813 nucleotides, coding for a putative protein of 270 amino acids to the termination codon. The IL-1 family motif and potential caspase cleavage site (necessary for production of the mature protein) is also present in the sequence. Molecular characterization of tammar wallaby IL-1β provides fundamental information necessary to progress the study of functional immune responses in this unique group of mammals.
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Affiliation(s)
- Lauren J Young
- Marsupial Immunology Research Laboratory, Centre for Environmental Management CQUniversity Australia, New South Wale, Australia.
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Unravelling causality from correlations: revealing the impacts of endemic ectoparasites on a protected species (tuatara). Parasitology 2009; 137:275-86. [DOI: 10.1017/s0031182009991314] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARYUnderstanding the impacts of endemic parasites on protected hosts is an essential element of conservation management. However, where manipulative experiments are unethical, causality cannot be inferred from observational correlative studies. Instead, we used an experimental structure to explore temporal associations between body condition of a protected reptile, the tuatara (Sphenodon punctatus) and infestation with ectoparasites (ticks and mites). We surveyed tuatara in a mark-recapture study on Stephens Island (New Zealand), which encompassed the pre-peak, peak and post-peak infestation periods for each ectoparasite. Tick loads during the peak infestation period were negatively related to body condition of tuatara. Body condition before the peak was not related to subsequent infestation rates; however, tick loads in the peak were negatively related to subsequent changes in body condition. Mite loads during the peak infestation period were not correlated with body condition of tuatara. Body condition before the peak had no effect on subsequent mite infestation rates, but mite loads of small males during the peak were negatively related to subsequent changes in body condition. Our results suggest that both ectoparasites reduce the body condition of tuatara, which has implications for the long-term conservation management of this host and its parasites.
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Molecular and morphological characterisation of Echinococcus from food producing animals in India. Vet Parasitol 2009; 165:58-65. [DOI: 10.1016/j.vetpar.2009.06.021] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Revised: 06/11/2009] [Accepted: 06/15/2009] [Indexed: 11/18/2022]
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Abstract
SUMMARYIn Australia, macropodids are common intermediate hosts for the cestodeEchinococcus granulosus, and sylvatic transmission is maintained via wild dogs. The parasite causes mortality in a number of macropodid species and the sylvatic cycle provides a source of infection to domestic livestock and humans. We determined the efficacy of the hydatid vaccine, EG95 in the tammar wallaby,Macropus eugenii, challenging either 1 or 9 months post-vaccination. EG95 provides similar protection to that seen in sheep (96–100%). Control tammars were significantly more likely to become infected (odds ratio 29·44; CI 4·13, 209·97;P=0·001) and to develop more cysts (count ratio 26·69; CI 5·83, 122·19;P<0·001). The vaccination may be beneficial if administered pre-release in captive breeding programmes for endangered macropodids. Further work to develop oral delivery methods may enable vaccine administration of wild animals and thereby a reduction in sylvatic transmission.
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Zhang W, Ross AG, McManus DP. Mechanisms of Immunity in Hydatid Disease: Implications for Vaccine Development. THE JOURNAL OF IMMUNOLOGY 2008; 181:6679-85. [DOI: 10.4049/jimmunol.181.10.6679] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Cystic echinococcosis in a wild population of the brush-tailed rock-wallaby (Petrogale penicillata), a threatened macropodid. Parasitology 2008; 135:715-23. [DOI: 10.1017/s0031182008004423] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARYInfection of small macropodids with the larval stage ofEchinococcus granulosuscan cause fatalities as well as significant pulmonary impairment and other adverse sequelae. The brush-tailed rock-wallaby (Petrogale penicillata) is a small macropodid listed as vulnerable on the IUCN'sRed List of Threatened Species. This study used radiographic techniques to determine the prevalence and severity of pulmonary hydatid infection and growth rates of hydatid cysts in a wild population of this macropodid. The overall prevalence was 15·3% (9/59 animals) with 20·0% (8/40 animals) of adults infected. During the study period, the death of at least 1 infected animal was directly attributed to pulmonary hydatidosis. Rapid cyst growth occurred in some animals (up to 43% increase in cyst volume in 3 months). Cyst volume reduced lung capacity by up to 17%. Secondary pulmonary changes were uncommon but, in 1 animal, resulted in reduction in lung capacity by approximately 50%. Infection was associated with a higher blood urea concentration, but no significant differences in other blood variables were detected. These results indicate that hydatid infection may be a significant risk to threatened populations of small macropodids and should be addressed in conservation management plans for these animals.
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