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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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Wright SE, Adkesson MJ, Schnelle AN, Allender MC, Cárdenas-Alayza S. Agreement Study between Total Leukocyte Count Methodologies in South American Sea Lions (Otaria byronia) and Peruvian Fur Seals (Arctocephalus australis). J Wildl Dis 2023; 59:315-321. [PMID: 37074799 DOI: 10.7589/jwd-d-22-00001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 11/23/2022] [Indexed: 04/20/2023]
Abstract
South American sea lions (Otaria byronia) and Peruvian fur seals (Arctocephalus australis) are sympatric species inhabiting the coastal Peruvian marine ecosystem. Declining abundance has prompted population health monitoring programs, including temporal monitoring of blood parameters. Several methods exist to determine total leukocyte count, yet no studies have evaluated agreement between methods in pinnipeds. We assessed agreement between total leukocyte counts determined by blood film estimate, Leuko-TIC, HemoCue, and UNOPETTE methods by using archival results from pinnipeds at Punta San Juan, Peru. Blood film estimates were prospectively performed, and resulting data were compared with retrospective leukocyte counts obtained from both species between 2009 and 2019 by using the other methodologies. Agreement in hematologic counts between methods was evaluated using Passing-Bablok regression and Bland-Altman plots (α=0.05). In total, 295 individuals (201 A. australis and 94 O. byronia) were included in the analysis. The blood film estimate method resulted in the highest leukocyte values (P<0.0001). Leuko-TIC counts were significantly higher than HemoCue counts (P<0.0001). Constant and proportional error was present in the agreement between the blood film estimate method and the other methods. Given the variation demonstrated between the different methodologies, additional research is needed to further evaluate agreement between these methodologies. The results underscore the importance of maintaining consistency in leukocyte count methodology for monitoring trends in population health over time. Method consistency may be the more important clinical consideration for assessing changes in leucocyte count over time and avoiding apparent changes depending on the methodology used.
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Affiliation(s)
- Sarah E Wright
- VCA Aurora Animal Hospital, 2600 West Galena Boulevard, Aurora, Illinois 60506, USA
| | - Michael J Adkesson
- Chicago Zoological Society, Brookfield Zoo, 3300 Golf Road, Brookfield, Illinois 60513, USA
| | - Amy N Schnelle
- Veterinary Diagnostic Laboratory, Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, Illinois 61802, USA
| | - Matthew C Allender
- Chicago Zoological Society, Brookfield Zoo, 3300 Golf Road, Brookfield, Illinois 60513, USA
- Wildlife Epidemiology Laboratory, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, 2001 South Lincoln Avenue, Urbana, Illinois 61802, USA
| | - Susana Cárdenas-Alayza
- Punta San Juan Program, Center for Environmental Sustainability, Universidad Peruana Cayetano Heredia, Av. Honorio Delgado 430, Lima 150102, Peru
- Centro para la Sostenibilidad Ambiental, Universidad Peruana Cayetano Heredia, Av. Armendáriz 445, Lima 15074, Peru
- Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Av. Honorio Delgado 430, Lima 15102, Peru
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3
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Seguel M, Molina-Burgos BE, Perez-Venegas DJ, Chiang G, Harrod C, DeRango E, Paves H. Shifts in maternal foraging strategies during pregnancy promote offspring health and survival in a marine top predator. Oecologia 2022; 199:343-354. [PMID: 35678930 DOI: 10.1007/s00442-022-05200-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 05/21/2022] [Indexed: 11/26/2022]
Abstract
The success of maternal foraging strategies during the rearing period can greatly impact the physiology and survival of dependent offspring. Surprisingly though, little is known on the fitness consequences of foraging strategies during the foetal period. In this study, we characterized variation in maternal foraging strategy throughout pregnancy in a marine top predator (South American fur seal, Arctocephalus australis), and asked if these shifts predicted neonatal health and postnatal survival. We found that during early pregnancy all pregnant females belonged to a single, homogenized foraging niche without evident clusters. Intriguingly though, during late pregnancy, individual fur seal mothers diverged into two distinct foraging niches characterized by a benthic-nearshore and a pelagic-offshore strategy. Females that shifted towards the benthic-nearshore strategy gave birth to pups with greater body mass, higher plasmatic levels of glucose and lower levels of blood urea nitrogen. The pups born to these benthic females were eight times more likely to survive compared to females using the pelagic-offshore foraging strategy during late pregnancy. These survival effects were mediated primarily by the impact of foraging strategies on neonatal glucose independent of protein metabolic profile and body mass. Benthic-nearshore foraging strategies during late pregnancy potentially allow for the greater maternal transfer of glucose to the foetus, leading to higher chances of neonatal survival. These results call for a deeper understanding of the balance between resource acquisition and allocation provided by distinct foraging polymorphisms during critical life-history periods, and how this trade-off may be adaptive under certain environmental conditions.
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Affiliation(s)
- Mauricio Seguel
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, 419 Gordon St, Guelph, ON, N1G2W1, Canada.
| | - Blanca E Molina-Burgos
- Facultad de Medicina Veterinaria y Agronomía, Universidad de las Americas, Manuel Montt 948, 7500000, Santiago, Chile
- Centro de Investigación Para La Sustentabilidad, Facultad de Ciencias de La Vida, Universidad Andres Bello, 8370251, Santiago, Chile
| | - Diego J Perez-Venegas
- Centro de Investigación y Gestión de Recursos Naturales (CIGREN), Instituto de Biología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Gustavo Chiang
- Departamento de Ecología y Biodiversidad and Centro de Investigación Para La Sustentabilidad (CIS), Facultad de Ciencias de La Vida, Universidad Andrés Bello, 8370251, Santiago, Chile
| | - Chris Harrod
- University of Antofagasta Stable Isotope Facility, University of Antofagasta, Antofagasta, Chile
- Instituto de Ciencias Naturales Alexander Von Humboldt, Universidad de Antofagasta, Antofagasta, Chile
- Nucleo Milenio INVASAL, Concepción, Chile
| | - Eugene DeRango
- Department of Animal Behaviour, Bielefeld University, Bielefeld, Germany
| | - Hector Paves
- Departamento de Ciencias Básicas, Facultad de Ciencias, Universidad Santo Tomas, Osorno, Chile
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Michael SA, Hayman DTS, Gray R, Roe WD. Clinical parameters of hypervirulent Klebsiella pneumoniae disease and ivermectin treatment in New Zealand sea lion (Phocarctos hookeri) pups. PLoS One 2022; 17:e0264582. [PMID: 35239682 PMCID: PMC8893627 DOI: 10.1371/journal.pone.0264582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 02/11/2022] [Indexed: 11/30/2022] Open
Abstract
Hypervirulent Klebsiella pneumoniae infection causes significant mortality of endangered New Zealand sea lion pups at Enderby Island, Auckland Islands. Gross necropsy and histopathology findings are well reported, but little is known about the clinical course of disease in affected pups. To determine factors feasible as clinical screening tools for hypervirulent K. pneumoniae in live pups, 150 pups over two field seasons (2016–18) were recruited shortly after birth for a prospective cohort study. A randomised controlled clinical treatment trial with the anthelmintic ivermectin was conducted concurrently and risk factor data and biological samples were collected approximately fortnightly. Treatment with ivermectin has been demonstrated to reduce the risk of hypervirulent K. pneumoniae mortality in pups, so effects on clinical parameters between the treated and control cohorts were also investigated. A broader sample of pups were monitored for clinical signs to investigate the course of disease in affected pups. Clinical signs, haematology and oral and rectal swabs to detect gastrointestinal carriage of hypervirulent K. pneumoniae were not useful for detection of disease prior to death. Of those pups that died due to hypervirulent K. pneumoniae, only 26.1% (18/69) had any clinical signs prior, likely a reflection of the peracute course of disease. On comparison of haematological parameters between ivermectin-treated and control pups, significantly lower total plasma protein and higher eosinophil counts were seen in control versus treated pups, however standard length as a surrogate for age was a more important influence on parameters overall than ivermectin treatment. This study also highlighted a cohort of pups with severe clinical signs suggestive of hypervirulent K. pneumoniae infection were lost to follow up at the end of the monitored season, which could be contributing to cryptic juvenile mortality.
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Affiliation(s)
- Sarah A. Michael
- Sydney School of Veterinary Science, The University of Sydney, Camperdown NSW, Australia
- School of Veterinary Science, Massey University, Palmerston North, New Zealand
- * E-mail:
| | - David T. S. Hayman
- Molecular Epidemiology and Public Health Laboratory, Hopkirk Research Institute, Massey University, Palmerston North, New Zealand
| | - Rachael Gray
- Sydney School of Veterinary Science, The University of Sydney, Camperdown NSW, Australia
| | - Wendi D. Roe
- School of Veterinary Science, Massey University, Palmerston North, New Zealand
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CLINICO-PATHOLOGIC FINDINGS AND PATHOGEN SCREENING IN FUR SEALS (ARCTOCEPHALUS AUSTRALIS AND ARCTOCEPHALUS TROPICALIS) STRANDED IN SOUTHEASTERN BRAZIL, 2018. J Wildl Dis 2021; 58:86-99. [PMID: 34724048 DOI: 10.7589/jwd-d-21-00060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 07/29/2021] [Indexed: 11/20/2022]
Abstract
Among pinnipeds, four Otariidae species (eared seals) have been reported as occasional or frequent vagrants along the coast of Brazil, mainly in the southern region. These animals usually arrive debilitated during winter and are directed to rehabilitation. Nevertheless, available information on sanitary aspects of stranded pinnipeds in Brazil is limited. Increased fur seal strandings (n=23) were recorded during the 2018 winter season in southeast Brazil (Iguape, Ilha Comprida, and Ilha do Cardoso, Sao Paulo State) compared to 2017 (n=2). Of these 23 fur seals, two were found dead and were in a good postmortem condition, and four died during rehabilitation and were subsequently necropsied. The remaining fur seals were not analyzed due to advanced decomposition (9/23) or successful rehabilitation (8/23). Herein, we report the antemortem hematology (n=4) and postmortem pathologic, parasitologic, and molecular analysis results as well as the most likely cause of stranding and/or death (CSD) in five free-ranging juvenile South American fur seals (Arctocephalus australis) and one free-ranging juvenile subantarctic fur seal (Arctocephalus tropicalis). All animals were males, and all but one had poor body condition. Pathologic examinations revealed a variety of lesions, predominantly hemodynamic disturbances, endoparasitism, and inflammatory disease processes of suspected infectious nature. Molecular analyses detected gammaherpesvirus infections in two South American seals and one subantarctic fur seal, Sarcocystis sp. in one subantarctic fur seal, and Neospora sp. in two South American fur seals. All seals were PCR-negative for morbillivirus, flavivirus, and Toxoplasma gondii. The most likely CSDs were: starvation (2), aspiration pneumonia (1), asphyxia (1), predator attack (1), and presumed systemic infectious disease (1). These findings expand the geographic range of various pathogens of pinnipeds and may be of value to first responders, clinicians, and diagnosticians.
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Kohyama K, Kiyota M, Inoshima Y. Longitudinal study of northern fur seal (Callorhinus ursinus) hematology. J Vet Med Sci 2021; 83:1128-1137. [PMID: 34092743 PMCID: PMC8349806 DOI: 10.1292/jvms.20-0645] [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] [Indexed: 12/03/2022] Open
Abstract
Although the causes have not been specified yet, wild populations of northern fur seals (Callorhinus ursinus) have been decreasing, which is
why conservation techniques such as captive breeding and health maintenance should be established. Hematological parameters can be used to maintain the health
status of northern fur seals kept in captivity for artificial reproduction and public education. Year-round fluctuations of blood parameters have not been
examined for northern fur seals due to the difficulties in obtaining serial blood samples from wild animals during the oceanic migration period from late autumn
to spring. In this study, blood samples were collected from four captive northern fur seals and analyzed monthly for more than three years to clarify the
seasonal fluctuation patterns in 14 hematological parameters. Many hematological parameters seemed to be seasonal patterns: summer–autumn and winter–spring;
leukocyte-related parameters were higher in summer and autumn than in winter and spring; erythrocyte-related parameters were lower in summer and autumn than in
winter and spring. Significant seasonal differences in nine of the 14 parameters were observed using a generalized linear mixed model (GLMM) analysis. These
results have improved our understanding of the seasonal patterns of hematological characteristics in the northern fur seal and can contribute to the health care
of protected or captive northern fur seals.
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Affiliation(s)
- Kaoru Kohyama
- Izu Mito Sea Paradise, 3-1 Uchiura-nagahama Numazu, Shizuoka 410-0224, Japan
| | - Masashi Kiyota
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Yasuo Inoshima
- Cooperative Department of Veterinary Medicine, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.,The United Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan.,Education and Research Center for Food Animal Health, Gifu University (GeFAH), 1-1 Yanagido, Gifu, Japan.,Joint Graduate School of Veterinary Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan
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Seguel M, Perez-Venegas D, Gutierrez J, Crocker DE, DeRango EJ. Parasitism Elicits a Stress Response That Allocates Resources for Immune Function in South American Fur Seals (Arctocephalus australis). Physiol Biochem Zool 2019; 92:326-338. [PMID: 30986114 DOI: 10.1086/702960] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Parasites can cause chronic stress in some animal species, and this type of stress response has been associated with adverse consequences for the host. In order to know whether parasitism elicited a stress response associated with decreased host fitness, hookworm (Uncinaria sp.) infection was studied in a colony of South American fur seals (Arctocephalus australis) in which hookworms infect nearly all pups born in a reproductive season. A parasite-free group was generated by treating a subset of pups with an antiparasitic drug before they developed patent hookworm infection. Stress and metabolic hormones, energy balance, and humoral and cellular immune parameters were measured in this group and hookworm-infected pups. Hookworms elicited a marked increase in plasma cortisol levels in fur seal pups. These hookworm-infected pups were able to maintain constant glucose levels, despite losing body mass over the course of infection potentially because of increased protein catabolism. Infected pups were able to mount an effective immune response against the parasite and eliminated hookworms from the intestine, recovering partial body mass lost as a result of hookworm infection at the end of the study period. As shown in previous studies, adequate glucose levels are critical for proper T lymphocyte reactivity, and it is possible that, through activation of a stress response, energy can be readily available for immune response against the parasite contributing to early recovery from infection. Although there are potential fitness costs to mounting a sustained stress response, these could also be adaptive and promote survival during critical life-history stages.
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Montalva F, Pérez‐Venegas D, Gutiérrez J, Seguel M. The contrasting hidden consequences of parasitism: Effects of a hematophagous nematode ( Uncinaria sp.) in the development of a marine mammal swimming behavior. Ecol Evol 2019; 9:3689-3699. [PMID: 31015959 PMCID: PMC6468065 DOI: 10.1002/ece3.4914] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 12/05/2018] [Accepted: 12/21/2018] [Indexed: 11/10/2022] Open
Abstract
Parasites are an important part of ecosystems, playing a critical role in their equilibrium. However, the consequences of parasitism beyond the direct effects associated with disease and mortality are not completely understood. This gap in knowledge is in part due to the difficulties to isolate the effect of single parasite species on physiological and behavioral traits in natural systems.The South American fur seal (Arctocephalus australis)-hookworm (Uncinaria sp.) interaction offers an ideal system to overcome these difficulties and study the behavioral and physiological effects of parasites in their hosts.Hookworms cause stunted growth and anemia in pinniped pups, which could affect early life active behaviors such as swimming. The aim of this study was to determine the effects of hookworms (Uncinaria sp.) on the development of swimming capabilities in A. australis through physiological and ethological analyses.Higher parasite burden was associated with reduced growth rates and lower blood hemoglobin concentrations, whereas scaled body mass and blood hemoglobin levels had an important positive effect on the water activity of the pups. However, antihookworm treatment did not affect the level of water activity of the pups, and pups with high hookworm burden increased their time budget in water. This was probably related to lower maternal attendance in heavily parasitized pups, leaving these pups more time to perform water activities. Therefore, pups with heavy hookworm burden, despite having decreased growth rates and blood hemoglobin concentrations, compensated for their handicap in physiological traits related to swimming by spending more time in the water.This work offers new insights to understand the contrasting effects of parasites on aquatic organisms, and the compensatory mechanisms employed by infected animals to avoid the worst consequences of parasitism.
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Affiliation(s)
- Felipe Montalva
- Facultad de Ciencias BiológicasPontificia Universidad Católica de ChileSantiagoChile
| | - Diego Pérez‐Venegas
- PhD Program in Conservation Medicine, Facultad de Ciencias de la VidaUniversidad Andrés BelloSantiagoChile
| | - Josefina Gutiérrez
- Instituto de Patología Animal, Facultad de Ciencias VeterinariasUniversidad Austral de ChileValdiviaChile
- Programa de Investigación Aplicada en Fauna Silvestre, Facultad de Ciencias VeterinariasUniversidad Austral de ChileValdiviaChile
| | - Mauricio Seguel
- Department of Pathology, College of Veterinary MedicineUniversity of GeorgiaAthensGeorgia
- Present address:
Odum School of EcologyUniversity of GeorgiaAthensGeorgia
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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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10
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Seguel M, Montalva F, Perez-Venegas D, Gutiérrez J, Paves HJ, Müller A, Valencia-Soto C, Howerth E, Mendiola V, Gottdenker N. Immune-mediated hookworm clearance and survival of a marine mammal decrease with warmer ocean temperatures. eLife 2018; 7:38432. [PMID: 30398149 PMCID: PMC6245726 DOI: 10.7554/elife.38432] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 10/26/2018] [Indexed: 11/13/2022] Open
Abstract
Increases in ocean temperature are associated with changes in the distribution of fish stocks, and the foraging regimes and maternal attendance patterns of marine mammals. However, it is not well understood how these changes affect offspring health and survival. The maternal attendance patterns and immunity of South American fur seals were assessed in a rookery where hookworm disease is the main cause of pup mortality. Pups receiving higher levels of maternal attendance had a positive energy balance and a more reactive immune system. These pups were able to expel hookworms through a specific immune mediated mechanism and survived the infection. Maternal attendance was higher in years with low sea surface temperature, therefore, the mean hookworm burden and mortality increased with sea surface temperature over a 10-year period. We provide a mechanistic explanation regarding how changes in ocean temperature and maternal care affect infectious diseases dynamics in a marine mammal.
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Affiliation(s)
- Mauricio Seguel
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, United States
| | - Felipe Montalva
- Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, Santiago, Chile
| | - Diego Perez-Venegas
- PhD Program in Conservation Medicine, Facultad de Ecología y Recursos Naturales, Universidad Andrés Bello, Santiago, Chile
| | - Josefina Gutiérrez
- Programa de Investigación Aplicada en Fauna Silvestre, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile.,Facultad de Ciencias Veterinarias, Instituto de Patología Animal, Universidad Austral de Chile, Valdivia, Chile
| | - Hector J Paves
- Departamento de Ciencias Básicas, Universidad Santo Tomas, Osorno, Chile
| | - Ananda Müller
- Instituto de Ciencias Clínicas Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - Carola Valencia-Soto
- Programa de Investigación Aplicada en Fauna Silvestre, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - Elizabeth Howerth
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, United States
| | - Victoria Mendiola
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, United States
| | - Nicole Gottdenker
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, United States
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11
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Respiratory Mites ( Orthohalarachne diminuata) and β-hemolytic Streptococci-Associated Bronchopneumonia Outbreak in South American Fur Seal Pups ( Arctocephalus australis). J Wildl Dis 2018; 54:380-385. [PMID: 29369727 DOI: 10.7589/2017-09-214] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Although mites of the Orthohalarachne genus are common parasites of otariids, their role as agents of disease and in causing population-level mortality is unknown. In the austral summer of 2016, there was an increase in mortality among South American fur seal ( Arctocephalus australis) pups at Guafo Island, Northern Chilean Patagonia. Pups found dead or terminally ill had moderate to marked, multifocal, mucopurulent bronchopneumonia associated with large numbers of respiratory mites ( Orthohalarachne diminuata) and rare Gram-positive cocci. In lung areas less affected by bronchopneumonia, acute interstitial pneumonia with marked congestion and scant hemorrhage was evident. Bacteria from pups dying of bronchopneumonia were isolated and identified as Streptococcus marimammalium and Streptococcus canis. Respiratory mites obstructed airflow, disrupted airway epithelial lining, and likely facilitated the proliferation of pathogenic β-hemolytic streptococci, leading to severe bronchopneumonia and death of fur seal pups. An abrupt increase in sea surface temperature in Guafo Island corresponded to the timing of the bronchopneumonia outbreak. The potential role of environmental factors in the fur seal pup mortality warrants further study.
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Seguel M, Muñoz F, Montalva F, Perez-Venegas D, Pavés H, Gottdenker N. Kelp and dolphin gulls cause perineal wounds in South American fur seal pups ( Arctocephalus australis) at Guafo Island, Chilean Patagonia. ROYAL SOCIETY OPEN SCIENCE 2017; 4:170638. [PMID: 28791178 PMCID: PMC5541573 DOI: 10.1098/rsos.170638] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 06/27/2017] [Indexed: 06/07/2023]
Abstract
During five reproductive seasons, we documented the presence, extent and origin of perineal wounds in South American fur seal pups (Arctocephalus australis) on Guafo Island, Northern Chilean Patagonia. The seasonal prevalence of perineal wounds ranged from 5 to 9%, and new cases were more common at the end of the breeding season (February), when pups were on average two months old and were actively expelling hookworms (Uncinaria sp). Histologically, wounds corresponded to marked ulcerative lymphoplasmacytic and histiocytic dermatitis with granulation tissue and mixed bacterial colonies. In 2015 and 2017, kelp gulls (Larus dominicanus) and dolphin gulls (Leucophaeus scoresbii) were observed picking and wounding the perineal area of marked pups. This behaviour occurred more frequently after the pups' defecation, when sea gulls engaged in consumption of pups' faeces. The affected pups usually had moderate to marked hookworm infections along with bloody diarrhoea and anaemia. Pups with severe wounds (23% of affected animals) had swollen perineal areas and signs of secondary systemic bacterial infection. We propose that seagulls on Guafo Island have learned to consume remains of blood and parasites in the faeces of pups affected by hookworm infection, causing perineal wounds during this process. We conclude that this perineal wounding is an unintentional, occasional negative effect of an otherwise commensal gull-fur seal relationship.
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Affiliation(s)
- Mauricio Seguel
- Department of Pathology, University of Georgia, College of Veterinary Medicine, Athens, GA, USA
| | - Francisco Muñoz
- Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile
| | - Felipe Montalva
- Facultad de Ciencias, Departamento de Biología Marina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Diego Perez-Venegas
- Conservation Medicine Program and Departamento de Ecología y Biodiversidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, 252 Republica St., Santiago, Chile
| | - Héctor Pavés
- Departamento de Ciencias Básicas, Universidad Santo Tomas, Los Carrera 753, Osorno, Chile
| | - Nicole Gottdenker
- Department of Pathology, University of Georgia, College of Veterinary Medicine, Athens, GA, USA
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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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