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Lindsay SA, Fulham M, Caraguel CGB, Gray R. Mitigating disease risk in an endangered pinniped: early hookworm elimination optimizes the growth and health of Australian sea lion pups. Front Vet Sci 2023; 10:1161185. [PMID: 37180065 PMCID: PMC10168540 DOI: 10.3389/fvets.2023.1161185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 04/04/2023] [Indexed: 05/15/2023] Open
Abstract
The Australian sea lion (Neophoca cinerea) experiences high pup mortality of seasonally alternating severity, partly attributed to endemic hookworm (Uncinaria sanguinis) infection. To further explore health outcomes of early hookworm elimination, a treatment trial was conducted at Seal Bay Conservation Park, South Australia, over consecutive lower and higher mortality breeding seasons (2019, 19.2%; 2020-1; 28.9%). Pups (n = 322) were stratified into two age cohorts (median 14 d and 24 d recruitment ages) and randomly assigned to treated (topical ivermectin 500 μg/kg) or control (untreated) groups. A younger prepatent cohort <14 d old (median 10 d) was identified a posteriori. A seasonally independent growth benefit resulted from hookworm elimination across all age cohorts. The greatest relative improvements (bodyweight + 34.2%, standard length + 42.1%; p ≤ 0.001) occurred in the month post-treatment, in the youngest prepatent cohort. A significant benefit of lesser magnitude (bodyweight + 8.6-11.6%, standard length + 9.5-18.4%; p ≤ 0.033) persisted up to 3 months across all age cohorts - greatest in the youngest pups. Treatment resulted in immediate improvement in hematological measures of health - decreased anemia and inflammation severity (p ≤ 0.012). These results enhance our understanding of host-parasite-environment interactions within the context of hematological ontogenesis, confirm the seasonally independent benefits of hookworm disease intervention, and further inform conservation recommendations for this endangered species.
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Affiliation(s)
- Scott A. Lindsay
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Camperdown, NSW, Australia
- Faculty of Science, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, Australia
| | - Mariel Fulham
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Camperdown, NSW, Australia
| | - Charles G. B. Caraguel
- Faculty of Science, School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, SA, Australia
| | - Rachael Gray
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Camperdown, NSW, Australia
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2
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Fulham M, Power M, Gray R. Gut microbiota of endangered Australian sea lion pups is unchanged by topical ivermectin treatment for endemic hookworm infection. Front Microbiol 2022; 13:1048013. [PMID: 36601397 PMCID: PMC9806137 DOI: 10.3389/fmicb.2022.1048013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 12/02/2022] [Indexed: 12/23/2022] Open
Abstract
The gut microbiota is essential for the development and maintenance of the hosts' immune system. Disturbances to the gut microbiota in early life stages can result in long-lasting impacts on host health. This study aimed to determine if topical ivermectin treatment for endemic hookworm (Uncinaria sanguinis) infection in endangered Australian sea lion (Neophoca cinerea) pups resulted in gut microbial changes. The gut microbiota was characterised for untreated (control) (n = 23) and treated (n = 23) Australian sea lion pups sampled during the 2019 and 2020/21 breeding seasons at Seal Bay, Kangaroo Island. Samples were collected pre- and post-treatment on up to four occasions over a four-to-five-month period. The gut microbiota of untreated (control) and treated pups in both seasons was dominated by five bacterial phyla, Fusobacteria, Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes. A significant difference in alpha diversity between treatment groups was seen in pups sampled during the 2020/21 breeding season (p = 0.008), with higher richness and diversity in treated pups. Modelling the impact of individual pup identification (ID), capture, pup weight (kg), standard length (cm), age and sex on beta diversity revealed that pup ID accounted for most of the variation (35% in 2019 and 42% in 2020/21), with pup ID, capture, and age being the only significant contributors to microbial variation (p < 0.05). There were no statistically significant differences in the composition of the microbiota between treatment groups in both the 2019 and 2020/21 breeding seasons, indicating that topical ivermectin treatment did not alter the composition of the gut microbiota. To our knowledge, this is the first study to characterise the gut microbiota of free-ranging Australian pinniped pups, compare the composition across multiple time points, and to consider the impact of parasitic treatment on overall diversity and microbial composition of the gut microbiota. Importantly, the lack of compositional changes in the gut microbiota with treatment support the utility of topical ivermectin as a safe and minimally invasive management strategy to enhance pup survival in this endangered species.
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Affiliation(s)
- Mariel Fulham
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camperdown, NSW, Australia
| | - Michelle Power
- School of Natural Sciences, Faculty of Science and Engineering, Macquarie University, North Ryde, NSW, Australia
| | - Rachael Gray
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camperdown, NSW, Australia,*Correspondence: Rachael Gray,
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Taylor S, Terkildsen M, McQuilty R, Lee D, Wing-Simpson A, Gray R. Non-essential heavy metals and protective effects of selenium against mercury toxicity in endangered Australian sea lion (Neophoca cinerea) pups with hookworm disease. ENVIRONMENT INTERNATIONAL 2022; 169:107521. [PMID: 36148712 DOI: 10.1016/j.envint.2022.107521] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 08/06/2022] [Accepted: 09/11/2022] [Indexed: 06/16/2023]
Abstract
The endangered Australian sea lion, Neophoca cinerea, faces ongoing population decline. Identification of key threats to N. cinerea population recovery, including disease and pollutants, is an objective of the species' recovery plan. Previous studies have identified Uncinaria sanguinis, an intestinal nematode, as a significant cause of disease and mortality in N. cinerea pups. Given the impact of heavy metals on the immune response, investigation of these pollutants is critical. To this end, the concentrations of arsenic (As), total mercury (Hg), cadmium (Cd), chromium (Cr), lead (Pb) and selenium (Se) were determined in blood collected from N. cinerea pups sampled during the 2017/18, 2019 and 2020/21 breeding seasons at Seal Bay Conservation Park, South Australia. Significant differences (p < 0.05) in Hg, As, Cr, and Se concentrations and molar ratio of Se:Hg were seen between breeding seasons. Pup age, maternal parity and inter-individual foraging behaviour were considered factors driving these differences. The concentrations of Hg (357, 198 and 241 µg/L) and As (225, 834 and 608 µg/L) were high in 2017/18, 2019 and 2020/21 respectively with Hg concentrations in the blood of N. cinerea pups above toxicological thresholds reported for marine mammals. The concentration of Se (1332, 647, 763 µg/L) and molar ratio of Se:Hg (9.47, 7.98 and 6.82) were low compared to other pinniped pups, indicating potential vulnerability of pups to the toxic effects of Hg. Significant (p < 0.05) negative associations for Pb and Cd with several red blood cell parameters suggest they could be exacerbating the anaemia caused by hookworm disease. Temporal (age-related) changes in element concentrations were also seen, such that pup age needs to be considered when interpreting bioaccumulation patterns. Further investigation of the role of elevated heavy metal concentrations on N. cinerea pup health, disease and development is recommended, particularly with respect to immunological impacts.
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Affiliation(s)
- Shannon Taylor
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camperdown, NSW 2006, Australia
| | | | - Robert McQuilty
- Department of Chemical Pathology, Royal Prince Alfred Hospital, Camperdown, Sydney 2050, Australia
| | - David Lee
- Department of Chemical Pathology, Royal Prince Alfred Hospital, Camperdown, Sydney 2050, Australia
| | - Aileen Wing-Simpson
- Department of Chemical Pathology, Royal Prince Alfred Hospital, Camperdown, Sydney 2050, Australia
| | - Rachael Gray
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camperdown, NSW 2006, Australia.
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4
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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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Meza Cerda MI, Gray R, Thomson PC, Butcher L, Simpson K, Cameron A, Marcus AD, Higgins DP. Developing Immune Profiles of Endangered Australian Sea Lion ( Neophoca cinerea) Pups Within the Context of Endemic Hookworm ( Uncinaria sanguinis) Infection. Front Vet Sci 2022; 9:824584. [PMID: 35529837 PMCID: PMC9069138 DOI: 10.3389/fvets.2022.824584] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 03/28/2022] [Indexed: 11/13/2022] Open
Abstract
As a top predator, the endangered Australian sea lion (Neophoca cinerea) is a sentinel of ecosystem change, where population trends can reflect broader shifts in the marine environment. The population of this endemic pinniped was historically diminished by commercial sealing, and recovery has been slowed by fishery interactions, disease and, potentially, pollutants. Hookworm infects 100% of neonatal pups and has been identified as a contributor to population decline. Here, a multivariable approach using traditional serological and novel molecular tools such as qPCR and ddPCR was used to examine immune phenotypes of developing Australian sea lion pups infected with the endemic hookworm (Uncinaria sanguinis) from two South Australian colonies. Results show changing immunophenotypes throughout the patent period of infection represented by pro-inflammatory cytokines (IL-6), IgG and acute-phase proteins. Although cytokines may prove useful as markers of resistance, in this study, IL-6 is determined to be an early biomarker of inflammation in Australian sea lion pups, excluding the alternative hypothesis. Additionally, immunological differences between animals from high- and low-intensity hookworm seasons, as well as ivermectin-treated animals, indicate hookworm infection modulation of the host immune response, as evidenced by a lower IL-6 mRNA expression in the non-treated groups. This study of the Australian sea lion is an example of an ecoimmunological approach to disease investigation, which can be applied to evaluate the impact of environmental and anthropogenic factors on susceptibility to infectious diseases in free-ranging species
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Affiliation(s)
- María-Ignacia Meza Cerda
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Rachael Gray
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Peter C Thomson
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Loreena Butcher
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Kelly Simpson
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Abby Cameron
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Alan D Marcus
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
| | - Damien P Higgins
- Faculty of Science, Sydney School of Veterinary Science, The University of Sydney, Sydney, NSW, Australia
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6
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Komnenou AT, Gkafas GA, Kofidou E, Sarantopoulou J, Exadactylos A, Tounta E, Koemtzopoulos K, Dendrinos P, Karamanlidis AA, Gulland F, Papadopoulos E. First Report of Uncinaria hamiltoni in Orphan Eastern Mediterranean Monk Seal Pups in Greece and Its Clinical Significance. Pathogens 2021; 10:pathogens10121581. [PMID: 34959536 PMCID: PMC8708642 DOI: 10.3390/pathogens10121581] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/29/2021] [Accepted: 12/01/2021] [Indexed: 11/17/2022] Open
Abstract
The Mediterranean monk seal (Monachus monachus) is classified by the IUCN as “endangered,” with a global population estimated to number fewer than 800 individuals. Our understanding of the biology and health status of the species is still limited, rendering every medical case a challenge for conservationists and veterinary clinicians. Although studying and managing disease in wild marine hosts is complex and challenging, studying and mitigating the effects of any disease to the Mediterranean monk seal is of utmost importance for conservation. The aim of this study was to document for the first time the presence of the hookworm Uncinaria hamiltoni in rehabilitated Mediterranean monk seal pups in Greece. A detailed examination protocol was followed for all pups that live-stranded over 30 years in 22 different locations, including physical, parasitological, and other examinations. Hookworms (adults and/or eggs) were detected in all the fecal samples, from all animals. Molecular identification using MtDNA (COI) and ribosomal DNA (D2/D3 28S and internal transcribed spacer [ITS] regions) identified the nematode species as Uncinaria hamiltoni. The clinical impacts and the benefits of anthelmintic treatment as a tool for the conservation management of the species are discussed.
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Affiliation(s)
- Anastasia Th. Komnenou
- School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, 54627 Thessaloniki, Greece; (A.T.K.); (E.K.)
- MOm/Hellenic Society for the Study and Protection of the Monk Seal, 10682 Athens, Greece; (E.T.); (K.K.); (P.D.); (A.A.K.)
| | - George A. Gkafas
- Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, 38446 Volos, Greece; (G.A.G.); (J.S.); (A.E.)
| | - Evangelia Kofidou
- School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, 54627 Thessaloniki, Greece; (A.T.K.); (E.K.)
| | - Joanne Sarantopoulou
- Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, 38446 Volos, Greece; (G.A.G.); (J.S.); (A.E.)
| | - Athanasios Exadactylos
- Department of Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, 38446 Volos, Greece; (G.A.G.); (J.S.); (A.E.)
| | - Eleni Tounta
- MOm/Hellenic Society for the Study and Protection of the Monk Seal, 10682 Athens, Greece; (E.T.); (K.K.); (P.D.); (A.A.K.)
| | - Kimon Koemtzopoulos
- MOm/Hellenic Society for the Study and Protection of the Monk Seal, 10682 Athens, Greece; (E.T.); (K.K.); (P.D.); (A.A.K.)
| | - Panagiotis Dendrinos
- MOm/Hellenic Society for the Study and Protection of the Monk Seal, 10682 Athens, Greece; (E.T.); (K.K.); (P.D.); (A.A.K.)
| | - Alexandros A. Karamanlidis
- MOm/Hellenic Society for the Study and Protection of the Monk Seal, 10682 Athens, Greece; (E.T.); (K.K.); (P.D.); (A.A.K.)
| | - Frances Gulland
- Karen C. Drayer Wildlife Heath Center, School of Veterinary Medicine, University of California, Davis, CA 95616, USA;
- Marine Mammal Commission, Bethesda, MD 20814, USA
| | - Elias Papadopoulos
- School of Veterinary Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, 54627 Thessaloniki, Greece; (A.T.K.); (E.K.)
- Correspondence: ; Tel.: +30-6944882872
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7
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Lindsay SA, Caraguel CG, Gray R. Topical ivermectin is a highly effective seal 'spot-on': A randomised trial of hookworm and lice treatment in the endangered Australian sea lion ( Neophoca cinerea). Int J Parasitol Parasites Wildl 2021; 16:275-284. [PMID: 34877253 PMCID: PMC8633868 DOI: 10.1016/j.ijppaw.2021.11.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/10/2021] [Accepted: 11/10/2021] [Indexed: 12/03/2022]
Abstract
The Australian sea lion (Neophoca cinerea) is an endangered and declining otariid species, with a high rate of pup mortality associated with endemic hookworm (Uncinaria sanguinis) infection a suspected contributor to this decline. Injected ivermectin is an effective treatment for Uncinaria sp. in otariids, with optimal outcomes achieved by the early treatment of pups prior to disease development. This randomised controlled trial evaluated the effectiveness of the novel use of a topical ivermectin formulation against hookworm infection and lice (Antarctophthirus microchir) infestation, in comparison with injected ivermectin. During the 2017 breeding season at Dangerous Reef, South Australia, pups ≤ 70 cm in standard length (≤ 2 weeks of age; n = 85) were randomised to single dose topical (500 μg/kg spot-on; n = 27) or injected (200 μg/kg subcutaneous; n = 29) ivermectin treatment groups, or to an untreated control group (n = 29). Topical ivermectin was highly effective for U. sanguinis elimination, and not significantly different to the injected formulation (estimated effectiveness 96.4% and 96.8%, respectively; P > 0.05). Its application resulted in an 81.6% reduction and 62.7% additional clearance for A. microchir infestation by 15-24 days post-treatment, compared with untreated control pups (also not significantly different to injected ivermectin; 83.1% and 59.4%, respectively; P > 0.05). Treatment with either ivermectin formulation significantly ameliorated increases in inflammatory markers detected in the blood of untreated control pups - peripheral blood eosinophil counts (persisting to 36-41 days post-recruitment P < 0.05) and increased plasma protein concentrations (15-24 days post-recruitment; P < 0.05). Further, an initial short-term decrease in body condition in the control group was not observed in either of the treatment groups. This study demonstrates that topical ivermectin is an effective antiparasitic treatment in N. cinerea. It offers an alternative administration method for ivermectin delivery to a young pup cohort in this species, and an alternative, minimally invasive management tool for species conservation.
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Affiliation(s)
- Scott A. Lindsay
- Sydney School of Veterinary Science, The University of Sydney, Camperdown, New South Wales, Australia
- School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, South Australia, Australia
| | - Charles G.B. Caraguel
- School of Animal and Veterinary Sciences, The University of Adelaide, Roseworthy, South Australia, Australia
| | - Rachael Gray
- Sydney School of Veterinary Science, The University of Sydney, Camperdown, New South Wales, Australia
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Bilgmann K, Armansin N, Ferchaud A, Normandeau E, Bernatchez L, Harcourt R, Ahonen H, Lowther A, Goldsworthy S, Stow A. Low effective population size in the genetically bottlenecked Australian sea lion is insufficient to maintain genetic variation. Anim Conserv 2021. [DOI: 10.1111/acv.12688] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- K. Bilgmann
- Department of Biological Sciences Macquarie University Sydney Australia
| | - N. Armansin
- Department of Biological Sciences Macquarie University Sydney Australia
| | - A.L. Ferchaud
- Département de Biologie Institut de Biologie Intégrative et des Systèmes (IBIS) Université Laval Québec QC Canada
| | - E. Normandeau
- Département de Biologie Institut de Biologie Intégrative et des Systèmes (IBIS) Université Laval Québec QC Canada
| | - L. Bernatchez
- Département de Biologie Institut de Biologie Intégrative et des Systèmes (IBIS) Université Laval Québec QC Canada
| | - R. Harcourt
- Department of Biological Sciences Macquarie University Sydney Australia
| | - H. Ahonen
- Department of Biological Sciences Macquarie University Sydney Australia
- Norwegian Polar Institute Tromsø Norway
| | | | - S.D. Goldsworthy
- South Australian Research and Development Institute Adelaide South Australia
| | - A. Stow
- Department of Biological Sciences Macquarie University Sydney Australia
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Taylor S, Terkildsen M, Stevenson G, de Araujo J, Yu C, Yates A, McIntosh RR, Gray R. Per and polyfluoroalkyl substances (PFAS) at high concentrations in neonatal Australian pinnipeds. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 786:147446. [PMID: 33971603 DOI: 10.1016/j.scitotenv.2021.147446] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 04/26/2021] [Accepted: 04/26/2021] [Indexed: 06/12/2023]
Abstract
Per and polyfluorinated substances (PFAS) exposure was investigated in Australian pinnipeds. Concentrations of 16 PFAS were measured in the livers of Australian sea lion (Neophoca cinerea), Australian fur seal (Arctocephalus pusillus doriferus) and a long-nosed Fur Seal (Arctocephalus forsteri) pup sampled between 2017 and 2020 from colonies in South Australia and Victoria. Findings reported in this study are the first documented PFAS concentrations in Australian pinnipeds. Median and observed range of values in ng/g wet weight were highest for perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) in the liver of N. cinerea (PFOS = 7.14, 1.00-16.9; PFOA = 2.73, 0.32-11.2; PFNA = 2.96, 0.61-8.22; n = 28), A. forsteri (PFOS = 15.98, PFOA = 2.02, PFNA = 7.86; n = 1) and A. p. doriferus (PFOS = 27.4, 10.5-2119; PFOA = 0.98, 0.32-52.2; PFNA = 2.50, 0.91-44.2; n = 20). PFAS concentrations in A. p. doriferus pups were significantly greater (p < 0.05) than in N. cinerea pups for all PFAS except PFOA and were of similar magnitude to those reported in northern hemisphere marine animals. These results demonstrate exposure differences in both magnitude and PFAS profiles for N. cinerea in South Australia and A. p. doriferus in Victoria. This study reports detectable PFAS concentrations in Australian pinniped pups indicating the importance of maternal transfer of these toxicants. As N. cinerea are endangered and recent declines in pup production has been reported for A. p. doriferus at the colony sampled, investigation of potential health impacts of these toxicants on Australian pinnipeds is recommended.
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Affiliation(s)
- Shannon Taylor
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camperdown, NSW 2006, Australia.
| | | | - Gavin Stevenson
- Australian Ultra-Trace Laboratory, National Measurement Institute, North Ryde, NSW 2113, Australia.
| | - Jesuina de Araujo
- Australian Ultra-Trace Laboratory, National Measurement Institute, North Ryde, NSW 2113, Australia
| | - Chunhai Yu
- Australian Ultra-Trace Laboratory, National Measurement Institute, North Ryde, NSW 2113, Australia
| | - Alan Yates
- Australian Ultra-Trace Laboratory, National Measurement Institute, North Ryde, NSW 2113, Australia.
| | - Rebecca R McIntosh
- Conservation Department, Phillip Island Nature Parks, PO Box 97, Cowes, Victoria 3922, Australia.
| | - Rachael Gray
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camperdown, NSW 2006, Australia.
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10
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Goldsworthy SD, Shaughnessy PD, Mackay AI, Bailleul F, Holman D, Lowther AD, Page B, Waples K, Raudino H, Bryars S, Anderson T. Assessment of the status and trends in abundance of a coastal pinniped, the Australian sea lion Neophoca cinerea. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Australian sea lions Neophoca cinerea are endemic to Australia, with their contemporary distribution restricted to South Australia (SA) and Western Australia (WA). Monitoring of the species has proved challenging due to prolonged breeding events that occur non-annually and asynchronously across their range. The most recent available data from 80 extant breeding sites (48 in SA, 32 in WA) enabled us to estimate the species-wide pup abundance to be 2739, with 82% (2246) in SA and 18% (493) in WA, mostly based on surveys conducted between 2014 and 2019. We evaluated 1776 individual site-surveys undertaken between 1970 and 2019 and identified admissible time-series data from 30 breeding sites, which revealed that pup abundance declined on average by 2.0% yr-1 (range 9.9% decline to 1.7% growth yr-1). The overall reduction in pup abundance over 3 generations (42.3 yr) was estimated to be 64%, with over 98% of Monte Carlo simulations producing a decline >50% over a 3-generation period, providing strong evidence that the species meets IUCN ‘Endangered’ criteria (decline ≥50% and ≤80%). The population is much smaller than previously estimated and is declining. There is a strong cline in regional abundances (increasing from west to east), with marked within-region heterogeneity in breeding site pup abundances and trends. Results from this study should improve consistency in the assessment of the species and create greater certainty among stakeholders about its conservation status. To facilitate species management and recovery, we prioritise key data gaps and identify factors to improve population monitoring.
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Affiliation(s)
- SD Goldsworthy
- South Australian Research and Development Institute, West Beach, South Australia 5024, Australia
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5005, Australia
| | - PD Shaughnessy
- South Australian Research and Development Institute, West Beach, South Australia 5024, Australia
- South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia
| | - AI Mackay
- South Australian Research and Development Institute, West Beach, South Australia 5024, Australia
| | - F Bailleul
- South Australian Research and Development Institute, West Beach, South Australia 5024, Australia
| | - D Holman
- Department for Environment and Water, Port Lincoln, South Australia 5066, Australia
| | - AD Lowther
- Norwegian Polar Institute, Framsentret, 9296 Tromsø, Norway
| | - B Page
- Department of Primary Industries and Regions, Urrbrae, South Australia 5064, Australia
| | - K Waples
- Department of Biodiversity, Conservation and Attractions, Kensington, Western Australia 6151, Australia
| | - H Raudino
- Department of Biodiversity, Conservation and Attractions, Kensington, Western Australia 6151, Australia
| | - S Bryars
- Department for Environment and Water, Adelaide, South Australia 5000, Australia
| | - T Anderson
- Helifarm, Ceduna, South Australia 5690, Australia
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11
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Meza Cerda MI, Gray R, Higgins DP. Cytokine RT-qPCR and ddPCR for immunological investigations of the endangered Australian sea lion ( Neophoca cinerea) and other mammals. PeerJ 2020; 8:e10306. [PMID: 33240637 PMCID: PMC7668205 DOI: 10.7717/peerj.10306] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 10/15/2020] [Indexed: 01/23/2023] Open
Abstract
Measurement of cytokine gene expression by reverse transcription quantitative polymerase chain reaction (RT-qPCR) is used widely to assess the immune system of animals and to identify biomarkers of disease, but its application is limited in wildlife species due to a lack of species-specific reagents. The free-ranging endangered Australian sea lion (Neophoca cinerea) experiences significant clinical disease and high pup mortality due to intestinal hookworm infection. Developing immunological tools specific to the species will aid in the assessment of drivers of disease and its impact in population demographics. This study describes the development and validation of cross-reactive RT-qPCR assays to measure five important cytokines involved in innate and Th1/Th2 responses (IL-6, TNFα, IFNγ, IL-4 and IL-10) in unstimulated blood samples from a range of different mammalian species including the Australian sea lion. All RT-qPCR assays efficiencies ranged between 87% (Ovis aries TNFα) and 111% (Bos taurus IL-10) and had strong linearity (R2). IL-4 and IFNγ gene expression for N. cinerea fell below the dynamic range (and therefore quantifiable limits) of RT-qPCR assays but were able to be quantified using the novel droplet digital PCR (ddPCR). This study delivers new immunological tools for eco-immunologists studying cytokine gene expression in wildlife species and is to our knowledge, the first cytokine ddPCR approach to be reported in a pinniped species.
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Affiliation(s)
- María-Ignacia Meza Cerda
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camperdown, NSW, Australia
| | - Rachael Gray
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camperdown, NSW, Australia
| | - Damien P Higgins
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camperdown, NSW, Australia
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12
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Abstract
Marine mammals are long-lived top predators with vagile lifestyles, which often inhabit remote environments. This is especially relevant in the oceanic waters around New Zealand and Australia where cetaceans and pinnipeds are considered as vulnerable and often endangered due to anthropogenic impacts on their habitat. Parasitism is ubiquitous in wildlife, and prevalence of parasitic infections as well as emerging diseases can be valuable bioindicators of the ecology and health of marine mammals. Collecting information about parasite diversity in marine mammals will provide a crucial baseline for assessing their impact on host and ecosystem ecology. New studies on marine mammals in New Zealand and Australian waters have recently added to our knowledge of parasite prevalence, life cycles and taxonomic relationships in the Australasian region, and justify a first host-parasite checklist encompassing all available data. The present checklist comprises 36 species of marine mammals, and 114 species of parasites (helminths, arthropods and protozoans). Mammal species occurring in New Zealand and Australian waters but not included in the checklist represent gaps in our knowledge. The checklist thus serves both as a guide for what information is lacking, as well as a practical resource for scientists working on the ecology and conservation of marine mammals.
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13
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Ferreira SCM, Hofer H, Madeira de Carvalho L, East ML. Parasite infections in a social carnivore: Evidence of their fitness consequences and factors modulating infection load. Ecol Evol 2019; 9:8783-8799. [PMID: 31410280 PMCID: PMC6686355 DOI: 10.1002/ece3.5431] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 05/19/2019] [Accepted: 06/08/2019] [Indexed: 01/03/2023] Open
Abstract
There are substantial individual differences in parasite composition and infection load in wildlife populations. Few studies have investigated the factors shaping this heterogeneity in large wild mammals or the impact of parasite infections on Darwinian fitness, particularly in juveniles. A host's parasite composition and infection load can be shaped by factors that determine contact with infective parasite stages and those that determine the host's resistance to infection, such as abiotic and social environmental factors, and age. Host-parasite interactions and synergies between coinfecting parasites may also be important. We test predictions derived from these different processes to investigate factors shaping infection loads (fecal egg/oocyte load) of two energetically costly gastrointestinal parasites: the hookworm Ancylostoma and the intracellular Cystoisospora, in juvenile spotted hyenas (Crocuta crocuta) in the Serengeti National Park, in Tanzania. We also assess whether parasite infections curtail survival to adulthood and longevity. Ancylostoma and Cystoisospora infection loads declined as the number of adult clan members increased, a result consistent with an encounter-reduction effect whereby adults reduced encounters between juveniles and infective larvae, but were not affected by the number of juveniles in a clan. Infection loads decreased with age, possibly because active immune responses to infection improved with age. Differences in parasite load between clans possibly indicate variation in abiotic environmental factors between clan den sites. The survival of juveniles (<365 days old) to adulthood decreased with Ancylostoma load, increased with age, and was modulated by maternal social status. High-ranking individuals with low Ancylostoma loads had a higher survivorship during the first 4 years of life than high-ranking individuals with high Ancylostoma loads. These findings suggest that high infection loads with energetically costly parasites such as hookworms during early life can have negative fitness consequences.
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Affiliation(s)
| | - Heribert Hofer
- Department of Ecological DynamicsLeibniz Institute for Zoo and Wildlife ResearchBerlinGermany
- Department of Veterinary MedicineFreie Universität BerlinBerlinGermany
- Department of Biology, Chemistry and PharmacyFreie Universität BerlinBerlinGermany
| | - Luis Madeira de Carvalho
- Centre for Interdisciplinary Research in Animal Health (CIISA), Faculdade de Medicina VeterinariaUniversidade de LisboaLisbonPortugal
| | - Marion L. East
- Department of Ecological DynamicsLeibniz Institute for Zoo and Wildlife ResearchBerlinGermany
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14
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George S, George A, Rolfe P, Emery D. Comparative assessment of faecal diagnostics for detection and predictive modelling of endemic Fasciola hepatica infection in sheep and cattle on Australian farms. Vet Parasitol 2019; 1:100001. [PMID: 32909553 PMCID: PMC7458369 DOI: 10.1016/j.vpoa.2018.100001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 12/14/2018] [Accepted: 12/14/2018] [Indexed: 01/30/2023]
Abstract
The diagnosis, monitoring and flukicide efficacy testing of fasciolosis on-farm is reliant on non-terminal methods. The coproantigen ELISA (cELISA) has been recommended for diagnosis of fasciolosis and associated flukicide efficacy testing as an alternative to fluke egg counts for monitoring parasitism. Recently experimental multi-age infections have suggested that the reliability of efficacy results can be improved by a second cELISA testing at 6 weeks post-treatment (wpt) in addition to the generally accepted 1 wpt. A field study was conducted to determine the suitability of faecal fluke egg counts (FFEC) and cELISA as diagnostic, drug efficacy testing and epidemiological tools on Australian sheep and cattle farms. Faecal samples from sheep and/or cattle on three endemic farms were taken at monthly intervals for 12 months and examined by both methods. Normal farm management was maintained during the study period and opportunistic efficacy testing, in line with each farm's normal flukicide management was undertaken. Additionally, the suitability of the Ollerenshaw Index as a predictive model for fasciolosis under Australian conditions was examined. While both diagnostics demonstrated their value in the farm environment, the current data demonstrate a distinct and significant increase in diagnostic sensitivity for epidemiological studies by using the two tests in parallel. The agreement between the two diagnostics was found to be higher in cattle, despite the poor sensitivity of FFEC in this species. Similar levels of agreement between the two tests were demonstrated at both sheep properties, regardless of the marked difference in the intensity of F. hepatica challenge. Linear regression models demonstrated the results of the two diagnostics utilized in parallel were explained substantially (R2 = 0.91) as were series data (R2 = 0.88) when the respective models were fitted. In contrast, the fitted models for FFEC (R2 = 0.54) and cELISA (R2 = 0.58) were poor explanations for test outcomes. The outcomes of these models support previous findings that suggest that the two diagnostic tests are best utilized together, particularly in parallel. The application of the Ollerenshaw Index to Australian conditions requires further investigation.
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Affiliation(s)
- S.D. George
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, New South Wales, Australia
- Elanco Animal Health, Yarrandoo R&D Centre, 245 Western Road, Kemps Creek, NSW, 2178, Australia
| | - A.J. George
- Elanco Animal Health, Yarrandoo R&D Centre, 245 Western Road, Kemps Creek, NSW, 2178, Australia
| | - P.F. Rolfe
- Elanco Animal Health, Yarrandoo R&D Centre, 245 Western Road, Kemps Creek, NSW, 2178, Australia
| | - D.L. Emery
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, New South Wales, Australia
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15
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Seguel M, Muñoz F, Perez-Venegas D, Müller A, Paves H, Howerth E, Gottdenker N. The life history strategy of a fur seal hookworm in relation to pathogenicity and host health status. Int J Parasitol Parasites Wildl 2018; 7:251-260. [PMID: 30069428 PMCID: PMC6067062 DOI: 10.1016/j.ijppaw.2018.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/05/2018] [Accepted: 07/07/2018] [Indexed: 01/23/2023]
Abstract
The strategies that parasites use to exploit their hosts can lead to adverse effects on human and animal populations. Here, we describe the life cycle, epidemiology, and consequences of hookworm (Uncinaria sp.) disease in South American fur seals (Arctocephalus australis), and propose that hookworm adaptation to fur seal life history traits has led to maximizing transmission at high levels of parasite-induced anemia and mortality. Fur seal pups acquire hookworms during their first days of life through their mothers' colostrum and most adult hookworms are expelled from the pups' intestine 30-65 days later. This gives hookworms little time to feed and reproduce. However, despite reaching high within-host densities, female hookworms do not decrease egg output, therefore pups with high hookworm burden contribute disproportionately to parasite egg shedding. These heavily infected pups also suffer severe anemia and high levels of hookworm-induced mortality. Alternative strategies to maximize total egg shedding and/or transmission, such as increased environmental survival of larval stages or avoidance of clearance, have not been developed by this hookworm. We propose that fur seal hookworms exploit a live fast-die young life history strategy, which translates to the highest levels of host anemia and mortality recorded among hookworms.
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Affiliation(s)
- Mauricio Seguel
- Department of Pathology, College of Veterinary Medicine, University of Georgia, 501 DW Brooks Dr, Athens, GA, 30602, USA
| | - Francisco Muñoz
- Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Isla Teja s/n, Valdivia, 509000, Chile
| | - Diego Perez-Venegas
- PhD Program in Conservation Medicine, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, Republica 239, Santiago, 8370134, Chile
| | - Ananda Müller
- Instituto de Ciencias Clínicas Veterinarias, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Isla Teja s/n, Valdivia, 5090000, Chile
| | - Hector Paves
- Departamento de Ciencias Básicas, Facultad de Ciencias, Universidad Santo Tomas, Los Carrera 753, Osorno, 5310431, Chile
| | - Elizabeth Howerth
- Department of Pathology, College of Veterinary Medicine, University of Georgia, 501 DW Brooks Dr, Athens, GA, 30602, USA
| | - Nicole Gottdenker
- Department of Pathology, College of Veterinary Medicine, University of Georgia, 501 DW Brooks Dr, Athens, GA, 30602, USA
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16
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Comparative ecology of Escherichia coli in endangered Australian sea lion (Neophoca cinerea) pups. INFECTION GENETICS AND EVOLUTION 2018; 62:262-269. [PMID: 29730275 DOI: 10.1016/j.meegid.2018.05.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 05/01/2018] [Accepted: 05/02/2018] [Indexed: 02/07/2023]
Abstract
The dissemination of human-associated bacteria into the marine environment has the potential to expose wildlife populations to atypical microbes that can alter the composition of the gut microbiome or act as pathogens. The objective of the study was to determine whether endangered Australian sea lion (Neophoca cinerea) pups from two South Australian colonies, Seal Bay, Kangaroo Island and Dangerous Reef, Spencer Gulf, have been colonised by human-associated Escherichia coli. Faecal samples (n = 111) were collected to isolate E. coli, and molecular screening was applied to assign E. coli isolates (n = 94) to phylotypes and detect class 1 integrons; mobile genetic elements that confer resistance to antimicrobial agents. E. coli phylotype distribution and frequency differed significantly between colonies with phylotypes B2 and D being the most abundant at Seal Bay, Kangaroo Island (55% and 7%) and Dangerous Reef, Spencer Gulf (36% and 49%), respectively. This study reports the first case of antimicrobial resistant E. coli in free-ranging Australian sea lions through the identification of class 1 integrons from an individual pup at Seal Bay. A significant relationship between phylotype and total white cell count (WCC) was identified, with significantly higher WCC seen in pups with human-associated phylotypes at Dangerous Reef. The difference in phylotype distribution and presence of human-associated E. coli suggests that proximity to human populations can influence sea lion gut microbiota. The identification of antimicrobial resistance in a free-ranging pinniped population provides crucial information concerning anthropogenic influences in the marine environment.
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17
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Seguel M, Gottdenker N. The diversity and impact of hookworm infections in wildlife. Int J Parasitol Parasites Wildl 2017; 6:177-194. [PMID: 28765810 PMCID: PMC5526439 DOI: 10.1016/j.ijppaw.2017.03.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/23/2017] [Accepted: 03/31/2017] [Indexed: 12/02/2022]
Abstract
Hookworms are blood-feeding nematodes that parasitize the alimentary system of mammals. Despite their high pathogenic potential, little is known about their diversity and impact in wildlife populations. We conducted a systematic review of the literature on hookworm infections of wildlife and analyzed 218 studies qualitative and quantitatively. At least 68 hookworm species have been described in 9 orders, 24 families, and 111 species of wild mammals. Black bears, red foxes, and bobcats harbored the highest diversity of hookworm species and Ancylostoma pluridentatum, A. tubaeforme, Uncinaria stenocephala and Necator americanus were the hookworm species with the highest host diversity index. Hookworm infections cause anemia, retarded growth, tissue damage, inflammation and significant mortality in several wildlife species. Anemia has been documented more commonly in canids, felids and otariids, and retarded growth only in otariids. Population- level mortality has been documented through controlled studies only in canines and eared seals although sporadic mortality has been noticed in felines, bears and elephants. The main driver of hookworm pathogenic effects was the hookworm biomass in a population, measured as prevalence, mean burden and hookworm size (length). Many studies recorded significant differences in prevalence and mean intensity among regions related to contrasts in local humidity, temperature, and host population density. These findings, plus the ability of hookworms to perpetuate in different host species, create a dynamic scenario where changes in climate and the domestic animal-human-wildlife interface will potentially affect the dynamics and consequences of hookworm infections in wildlife.
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Affiliation(s)
- Mauricio Seguel
- Department of Pathology, College of Veterinary Medicine, University of Georgia, 501 DW Brooks Dr, Athens, GA 30602, USA
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18
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Seguel M, Muñoz F, Navarrete MJ, Paredes E, Howerth E, Gottdenker N. Hookworm Infection in South American Fur Seal ( Arctocephalus australis) Pups. Vet Pathol 2016; 54:288-297. [PMID: 28207376 DOI: 10.1177/0300985816677151] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Tissues of South American fur seal pups naturally infected with hookworms ( Uncinaria sp) were examined. Hookworm infection was found in nearly all pups examined (132/140, 94%), and hookworm enteritis with secondary bacteremia was considered the cause of death in 46 (35%) pups. Common findings in these pups included severe hemorrhagic enteritis and numerous (mean intensity = 761.8) hookworms in the jejunum. Hookworms were recovered from the abdominal cavity in 12 of 55 pups (22%) examined through peritoneal wash; these pups had an average of 1343.3 intestinal hookworms and marked fibrinohemorrhagic peritonitis. In all pups that died as a consequence of hookworm infection, the intestinal villi were short, blunt, and fused, and there were variable numbers of free and intrahistiocytic gram-negative bacteria in submucosal hookworm feeding tracks, mesenteric lymph nodes, spleen, blood vessels, and liver sinusoids. Pups that died of causes unrelated to the hookworm infection (trauma) had hookworm feeding tracks confined to the apical portions of the mucosa, and moderate to marked catarrhal eosinophilic enteritis. The number of hookworms was negatively correlated with intestinal villous length and number of leukocytes in the intestine. Pups with hookworm peritoneal penetration had nematodes with little or no blood in the hookworm intestine, suggesting that lack of food for the nematode could be associated with peritoneal penetration. Findings suggest that the initial burden of larval infection, the level of the host tissue response, or a combination determine the number of nematodes in the intestine, the severity of hookworm tissue damage, and pup mortality.
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Affiliation(s)
- M Seguel
- 1 Department of Pathology, College of Veterinary Medicine, The University of Georgia, Athens, GA
| | - F Muñoz
- 2 Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - M J Navarrete
- 2 Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - E Paredes
- 2 Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - E Howerth
- 1 Department of Pathology, College of Veterinary Medicine, The University of Georgia, Athens, GA
| | - N Gottdenker
- 1 Department of Pathology, College of Veterinary Medicine, The University of Georgia, Athens, GA
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19
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Na-Ek P, Sanpool O, Jongthawin J, Anamnart W, Intapan PM, Chamavit P, Maleewong W. Restoration of hookworm egg development after prolonged storage in stool suspension. Parasitol Res 2016; 115:2817-23. [PMID: 27053130 DOI: 10.1007/s00436-016-5031-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Accepted: 03/23/2016] [Indexed: 11/25/2022]
Abstract
Hookworm infection is still prevalent in southern Thailand despite control measures. Hookworm eggs submerged for an extended period under water from rainfall or in latrines may not survive, but they may recover their ability to develop into infective larvae when exposed to atmospheric air. This study examined the survival of the hookworm eggs in stool suspension and the restoration of development capability after prolonged storage. In stool mass, eggs developed normally and yielded infective filariform larvae (FL) in 7 days. On the contrary, in 1:10 stool suspension, hookworm eggs were found to remain at the 4-8 cell stage; degenerated eggs were observed after 15 days of storage, and the number of degenerated eggs reached 80 % on day 30. Aeration of the suspension, or transferring to a Petri dish or agar plate, restored the capacity of eggs stored for up to 15 days to develop into FL; thereafter, the capacity declined sharply. Retardation of egg development under water or in stool suspension may be due to a lack of atmospheric air. Use of "night soil" from latrines as fertilizer may be one factor in maintaining hookworm transmission, as worm eggs can undergo normal development upon exposure to atmospheric air.
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Affiliation(s)
- Prasit Na-Ek
- School of Medicine, Walailak University, Thasala, Nakhon Si Thammarat, Thailand
| | - Oranuch Sanpool
- Department of Parasitology and Research and Diagnostic Center for Emerging Infectious Diseases, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Jurairat Jongthawin
- Department of Parasitology and Research and Diagnostic Center for Emerging Infectious Diseases, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Witthaya Anamnart
- School of Allied Health Sciences and Public Health, Walailak University, Thasala, Nakhon Si Thammarat, Thailand
| | - Pewpan M Intapan
- Department of Parasitology and Research and Diagnostic Center for Emerging Infectious Diseases, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Pennapa Chamavit
- Department of Parasitology, Faculty of Medical Technology, Huachiew Chalermprakiet University, Samut Prakan, Thailand
| | - Wanchai Maleewong
- Department of Parasitology and Research and Diagnostic Center for Emerging Infectious Diseases, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand.
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20
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Marcus AD, Higgins DP, Gray R. Ivermectin treatment of free-ranging endangered Australian sea lion (Neophoca cinerea) pups: effect on hookworm and lice infection status, haematological parameters, growth, and survival. Parasitol Res 2015; 114:2743-55. [DOI: 10.1007/s00436-015-4481-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 04/09/2015] [Indexed: 02/03/2023]
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21
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Lau Q, Chow N, Gray R, Gongora J, Higgins DP. Diversity of MHCDQBandDRBGenes in the Endangered Australian Sea Lion (Neophoca cinerea). J Hered 2015; 106:395-402. [DOI: 10.1093/jhered/esv022] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 03/25/2015] [Indexed: 01/26/2023] Open
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22
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East ML, Otto E, Helms J, Thierer D, Cable J, Hofer H. Does lactation lead to resource allocation trade-offs in the spotted hyaena? Behav Ecol Sociobiol 2015. [DOI: 10.1007/s00265-015-1897-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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23
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Marcus AD, Higgins DP, Gray R. Health assessment of free-ranging endangered Australian sea lion (Neophoca cinerea) pups: effect of haematophagous parasites on haematological parameters. Comp Biochem Physiol A Mol Integr Physiol 2015; 184:132-43. [PMID: 25724096 DOI: 10.1016/j.cbpa.2015.02.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/19/2015] [Accepted: 02/19/2015] [Indexed: 02/07/2023]
Abstract
Evaluation of the health status of free-ranging populations is important for understanding the impact of disease on individuals and on population demography and viability. In this study, haematological reference intervals were developed for free-ranging endangered Australian sea lion (Neophoca cinerea) pups within the context of endemic hookworm (Uncinaria sanguinis) infection and the effects of pathogen, host, and environment factors on the variability of haematological parameters were investigated. Uncinaria sanguinis was identified as an important agent of disease, with infection causing regenerative anaemia, hypoproteinaemia, and a predominantly lymphocytic-eosinophilic systemic inflammatory response. Conversely, the effects of sucking lice (Antarctophthirus microchir) were less apparent and infestation in pups appears unlikely to cause clinical impact. Overall, the effects of U. sanguinis, A. microchir, host factors (standard length, body condition, pup sex, moult status, and presence of lesions), and environment factors (capture-type and year of sampling) accounted for 26-65% of the total variance observed in haematological parameters. Importantly, this study demonstrated that anaemia in neonatal Australian sea lion pups is not solely a benign physiological response to host-environment changes, but largely reflects a significant pathological process. This impact of hookworm infection on pup health has potential implications for the development of foraging and diving behaviour, which would subsequently influence the independent survival of juveniles following weaning. The haematological reference intervals developed in this study can facilitate long-term health surveillance, which is critical for the early recognition of changes in disease impact and to inform conservation management.
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Affiliation(s)
- Alan D Marcus
- Faculty of Veterinary Science, The University of Sydney, McMaster Building B14, Camperdown, New South Wales 2006, Australia
| | - Damien P Higgins
- Faculty of Veterinary Science, The University of Sydney, McMaster Building B14, Camperdown, New South Wales 2006, Australia
| | - Rachael Gray
- Faculty of Veterinary Science, The University of Sydney, McMaster Building B14, Camperdown, New South Wales 2006, Australia.
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24
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Michael SA, Chilvers BL, Roe WD, Gartrell BD. Long-term survival and reproductive success of New Zealand sea lions (Phocarctos hookeri) treated with ivermectin as pups. WILDLIFE RESEARCH 2015. [DOI: 10.1071/wr15120] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Context
Hookworms (Uncinaria spp.) are a common parasite of neonatal fur seals and sea lions around the world and may contribute to decreased pup growth and survival. Removal of these parasitic burdens by administration of the anthelmintic ivermectin has been trialled in New Zealand (NZ) sea lion (Phocarctos hookeri) pups at Sandy Bay, Enderby Island, with initial benefits in growth and survival reported. Long-term effects, however, are not known.
Aims
To determine the impact of ivermectin treatment administered in the first month of life, on long-term survival and fecundity in a sample of NZ sea lion pups.
Methods
For a sample of treated and control pups born between 2002 and 2004, resighting data to 2012 was assessed with the Cox proportional hazards analysis to evaluate survival to maturity and fecundity.
Key results
Sample size was a limiting factor as juvenile survival was very low, but a trend of improved survival was observed in the ivermectin-treated group. Year of birth was significant due to the effects of a bacterial epizootic in the first year of the trial. Reproductive rate was not significantly different between groups.
Conclusions
The effect of disease and parasitism on the survival of NZ sea lions is apparent, contributing to early pup mortality, with potentially wider-ranging implications for juvenile survival and beyond.
Implications
Further research is warranted to investigate anthelmintic treatment of NZ sea lion pups as a safe and effective management tool to improve survival and recruitment in declining populations.
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25
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Catalano S, Lejeune M, van Paridon B, Pagan CA, Wasmuth JD, Tizzani P, Duignan PJ, Nadler SA. Morphological variability and molecular identification of Uncinaria spp. (Nematoda: Ancylostomatidae) from grizzly and black bears: new species or phenotypic plasticity? J Parasitol 2014; 101:182-92. [PMID: 25548982 DOI: 10.1645/14-621.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
The hookworms Uncinaria rauschi Olsen, 1968 and Uncinaria yukonensis ( Wolfgang, 1956 ) were formally described from grizzly ( Ursus arctos horribilis) and black bears ( Ursus americanus ) of North America. We analyzed the intestinal tracts of 4 grizzly and 9 black bears from Alberta and British Columbia, Canada and isolated Uncinaria specimens with anatomical traits never previously documented. We applied morphological and molecular techniques to investigate the taxonomy and phylogeny of these Uncinaria parasites. The morphological analysis supported polymorphism at the vulvar region for females of both U. rauschi and U. yukonensis. The hypothesis of morphological plasticity for U. rauschi and U. yukonensis was confirmed by genetic analysis of the internal transcribed spacers (ITS-1 and ITS-2) of the nuclear ribosomal DNA. Two distinct genotypes were identified, differing at 5 fixed sites for ITS-1 (432 base pairs [bp]) and 7 for ITS-2 (274 bp). Morphometric data for U. rauschi revealed host-related size differences: adult U. rauschi were significantly larger in black bears than in grizzly bears. Interpretation of these results, considering the historical biogeography of North American bears, suggests a relatively recent host-switching event of U. rauschi from black bears to grizzly bears which likely occurred after the end of the Wisconsin glaciation. Phylogenetic maximum parsimony (MP) and maximum likelihood (ML) analyses of the concatenated ITS-1 and ITS-2 datasets strongly supported monophyly of U. rauschi and U. yukonensis and their close relationship with Uncinaria stenocephala (Railliet, 1884), the latter a parasite primarily of canids and felids. Relationships among species within this group, although resolved by ML, were unsupported by MP and bootstrap resampling. The clade of U. rauschi, U. yukonensis, and U. stenocephala was recovered as sister to the clade represented by Uncinaria spp. from otariid pinnipeds. These results support the absence of strict host-parasite co-phylogeny for Uncinaria spp. and their carnivore hosts. Phylogenetic relationships among Uncinaria spp. provided a framework to develop the hypothesis of similar transmission patterns for the closely related U. rauschi, U. yukonensis, and U. stenocephala.
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Affiliation(s)
- Stefano Catalano
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB T2N 4Z6, Canada
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Haynes BT, Marcus AD, Higgins DP, Gongora J, Gray R, Šlapeta J. Unexpected absence of genetic separation of a highly diverse population of hookworms from geographically isolated hosts. INFECTION GENETICS AND EVOLUTION 2014; 28:192-200. [PMID: 25262830 DOI: 10.1016/j.meegid.2014.09.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 07/29/2014] [Accepted: 09/17/2014] [Indexed: 11/29/2022]
Abstract
The high natal site fidelity of endangered Australian sea lions (Neophoca cinerea) along the southern Australian coast suggests that their maternally transmitted parasitic species, such as hookworms, will have restricted potential for dispersal. If this is the case, we would expect to find a hookworm haplotype structure corresponding to that of the host mtDNA haplotype structure; that is, restricted among geographically separated colonies. In this study, we used a fragment of the cytochrome c oxidase I mitochondrial DNA (mtDNA) gene to investigate the diversity of hookworms (Uncinaria sanguinis) in N. cinerea to assess the importance of host distribution and ecology on the evolutionary history of the parasite. High haplotype (h=0.986) and nucleotide diversity (π=0.013) were seen, with 45 unique hookworm mtDNA haplotypes across N. cinerea colonies; with most of the variation (78%) arising from variability within hookworms from individual colonies. This is supported by the low genetic differentiation co-efficient (GST=0.007) and a high gene flow (Nm=35.25) indicating a high migration rate between the populations of hookworms. The haplotype network demonstrated no clear distribution and delineation of haplotypes according to geographical location. Our data rejects the vicariance hypothesis; that female host natal site fidelity and the transmammary route of infection restrict hookworm gene flow between N. cinerea populations and highlights the value of studies of parasite diversity and dispersal to challenge our understanding of parasite and host ecology.
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Affiliation(s)
- Benjamin T Haynes
- Faculty of Veterinary Science, The University of Sydney, New South Wales, Australia
| | - Alan D Marcus
- Faculty of Veterinary Science, The University of Sydney, New South Wales, Australia
| | - Damien P Higgins
- Faculty of Veterinary Science, The University of Sydney, New South Wales, Australia
| | - Jaime Gongora
- Faculty of Veterinary Science, The University of Sydney, New South Wales, Australia
| | - Rachael Gray
- Faculty of Veterinary Science, The University of Sydney, New South Wales, Australia
| | - Jan Šlapeta
- Faculty of Veterinary Science, The University of Sydney, New South Wales, Australia.
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