1
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Berger L, Skerratt LF, Kosch TA, Brannelly LA, Webb RJ, Waddle AW. Advances in Managing Chytridiomycosis for Australian Frogs: Gradarius Firmus Victoria. Annu Rev Anim Biosci 2024; 12:113-133. [PMID: 38358840 DOI: 10.1146/annurev-animal-021122-100823] [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] [Indexed: 02/17/2024]
Abstract
Extensive knowledge gains from research worldwide over the 25 years since the discovery of chytridiomycosis can be used for improved management. Strategies that have saved populations in the short term and/or enabled recovery include captive breeding, translocation into disease refugia, translocation from resistant populations, disease-free exclosures, and preservation of disease refuges with connectivity to previous habitat, while antifungal treatments have reduced mortality rates in the wild. Increasing host resistance is the goal of many strategies under development, including vaccination and targeted genetic interventions. Pathogen-directed strategies may be more challenging but would have broad applicability. While the search for the silver bullet solution continues, we should value targeted local interventions that stop extinction and buy time for evolution of resistance or development of novel solutions. As for most invasive species and infectious diseases, we need to accept that ongoing management is necessary. For species continuing to decline, proactive deployment and assessment of promising interventions are more valid than a hands-off, do-no-harm approach that will likely allow further extinctions.
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Affiliation(s)
- Lee Berger
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
| | - Lee F Skerratt
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
| | - Tiffany A Kosch
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
| | - Laura A Brannelly
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
| | - Rebecca J Webb
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
| | - Anthony W Waddle
- One Health Research Group, Melbourne Veterinary School, Faculty of Science, University of Melbourne, Werribee, Victoria, Australia; , , , ,
- Applied Biosciences, Macquarie University, Sydney, New South Wales, Australia;
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2
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Roth SA, Griffis-Kyle KL, Barnes MA. Batrachochytrium dendrobatidis in the Arid and Thermally Extreme Sonoran Desert. ECOHEALTH 2023; 20:370-380. [PMID: 38243042 DOI: 10.1007/s10393-023-01668-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 12/08/2023] [Indexed: 01/21/2024]
Abstract
Batrachochytrium dendrobatidis (Bd), the causative agent of the devastating global amphibian disease chytridiomycosis, was not projected to threaten amphibians in hot and arid regions due to its sensitivity to heat and desiccation. However, Bd is being detected more frequently than ever in hot and arid regions of Australia and the USA, challenging our current understanding of the environmental tolerances of the pathogen under natural conditions. We surveyed for Bd in an extremely hot and arid portion of the Sonoran Desert, where the pathogen is not projected to occur, and related presence and prevalence of the pathogen to local environmental conditions. We collected eDNA samples from isolated desert water sites including six tinajas and 13 catchments in June and August of 2020 and swabbed a total of 281 anurans of three species (red-spotted toad Anaxyrus punctatus, Couch's spadefoot Scaphiopus couchii, and the Sonoran Desert toad Incillius alvarius) across five catchments and six tinajas from June to September of 2020. Overall, Bd occurred at 68.4% of sites, despite extreme heat and aridity routinely exceeding tolerances established in laboratory studies. Average summer maximum air and water temperatures were 40.7°C and 30.7°C, respectively, and sites received an average of just 16.9 mm of precipitation throughout the summer monsoon season. Prevalence was low (5.7%) across species and life stage. Our results demonstrate that Bd is capable of persisting and infecting amphibians beyond its projected range, indicating a need to account for higher thermal tolerances when quantifying risk of Bd presence and infection.
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Affiliation(s)
- Sadie A Roth
- Department of Natural Resources Management, Texas Tech University, 2500 Broadway, Lubbock, TX, 79409, USA.
| | - Kerry L Griffis-Kyle
- Department of Natural Resources Management, Texas Tech University, 2500 Broadway, Lubbock, TX, 79409, USA
| | - Matthew A Barnes
- Department of Natural Resources Management, Texas Tech University, 2500 Broadway, Lubbock, TX, 79409, USA
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3
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Scheele BC, Heard GW, Cardillo M, Duncan RP, Gillespie GR, Hoskin CJ, Mahony M, Newell D, Rowley JJL, Sopniewski J. An invasive pathogen drives directional niche contractions in amphibians. Nat Ecol Evol 2023; 7:1682-1692. [PMID: 37550511 DOI: 10.1038/s41559-023-02155-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 07/07/2023] [Indexed: 08/09/2023]
Abstract
Global change is causing an unprecedented restructuring of ecosystems, with the spread of invasive species being a key driver. While population declines of native species due to invasives are well documented, much less is known about whether new biotic interactions reshape niches of native species. Here we quantify geographic range and realized-niche contractions in Australian frog species following the introduction of amphibian chytrid fungus Batrachochytrium dendrobatidis, a pathogen responsible for catastrophic amphibian declines worldwide. We show that chytrid-impacted species experienced proportionately greater contractions in niche breadth than geographic distribution following chytrid emergence. Furthermore, niche contractions were directional, with contemporary distributions of chytrid-impacted species characterized by higher temperatures, lower diurnal temperature range, higher precipitation and lower elevations. Areas with these conditions may enable host persistence with chytrid through lower pathogenicity of the fungus and/or greater demographic resilience. Nevertheless, contraction to a narrower subset of environmental conditions could increase host vulnerability to other threatening processes and should be considered in assessments of extinction risk and during conservation planning. More broadly, our results emphasize that biotic interactions can strongly shape species realized niches and that large-scale niche contractions due to new species interactions-particularly emerging pathogens-could be widespread.
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Affiliation(s)
- Ben C Scheele
- Fenner School of Environment and Society, Australian National University, Canberra, Australian Capital Territory, Australia.
- Macroevolution and Macroecology Group, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia.
| | - Geoffrey W Heard
- Terrestrial Ecosystem Research Network and Centre for Biodiversity and Conservation Science, University of Queensland, Brisbane, Queensland, Australia
| | - Marcel Cardillo
- Macroevolution and Macroecology Group, Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Richard P Duncan
- Centre for Conservation Ecology and Genomics, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Graeme R Gillespie
- Science, Economics and Insights Division, Department of Planning and Environment, Parramatta, New South Wales, Australia
- School of Biosciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Conrad J Hoskin
- College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Michael Mahony
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, New South Wales, Australia
| | - David Newell
- Faculty of Science and Engineering, Southern Cross University, Lismore, New South Wales, Australia
| | - Jodi J L Rowley
- Australian Museum Research Institute, Australian Museum, Sydney, New South Wales, Australia
- Centre for Ecosystem Science; School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Jarrod Sopniewski
- Fenner School of Environment and Society, Australian National University, Canberra, Australian Capital Territory, Australia
- School of Biological Sciences, University of Western Australia, Crawley, Western Australia, Australia
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4
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Sun D, Ellepola G, Herath J, Meegaskumbura M. Ecological Barriers for an Amphibian Pathogen: A Narrow Ecological Niche for Batrachochytrium salamandrivorans in an Asian Chytrid Hotspot. J Fungi (Basel) 2023; 9:911. [PMID: 37755019 PMCID: PMC10532633 DOI: 10.3390/jof9090911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 09/02/2023] [Accepted: 09/05/2023] [Indexed: 09/28/2023] Open
Abstract
The chytrid fungal pathogens Batrachochytrium salamandrivorans (Bsal) and B. dendrobatidis (Bd) are driving amphibian extinctions and population declines worldwide. As their origins are believed to be in East/Southeast Asia, this region is crucial for understanding their ecology. However, Bsal screening is relatively limited in this region, particularly in hotspots where Bd lineage diversity is high. To address this gap, we conducted an extensive Bsal screening involving 1101 individuals from 36 amphibian species, spanning 17 natural locations and four captive facilities in the biodiversity-rich Guangxi Zhuang Autonomous Region (GAR). Our PCR assays yielded unexpected results, revealing the complete absence of Bsal in all tested samples including 51 individuals with Bd presence. To understand the potential distribution of Bsal, we created niche models, utilizing existing occurrence records from both Asia and Europe. These models estimated potential suitable habitats for Bsal largely in the northern and southwestern parts of the GAR. Although Bsal was absent in our samples, the niche models identified 10 study sites as being potentially suitable for this pathogen. Interestingly, out of these 10 sites, Bd was detected at 8. This suggests that Bsal and Bd could possibly co-exist in these habitats, if Bsal were present. Several factors seem to influence the distribution of Bsal in Asia, including variations in temperature, local caudate species diversity, elevation, and human population density. However, it is climate-related factors that hold the greatest significance, accounting for a notable 60% contribution. The models propose that the specific climatic conditions of arid regions, primarily seen in the GAR, play a major role in the distribution of Bsal. Considering the increased pathogenicity of Bsal at stable and cooler temperatures (10-15 °C), species-dependent variations, and the potential for seasonal Bd-Bsal interactions, we emphasize the importance of periodic monitoring for Bsal within its projected range in the GAR. Our study provides deeper insights into Bsal's ecological niche and the knowledge generated will facilitate conservation efforts in amphibian populations devastated by chytrid pathogens across other regions of the world.
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Affiliation(s)
- Dan Sun
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530000, China; (D.S.)
| | - Gajaba Ellepola
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530000, China; (D.S.)
- Department of Zoology, Faculty of Science, University of Peradeniya, Peradeniya, Kandy 20400, Sri Lanka
| | - Jayampathi Herath
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530000, China; (D.S.)
- School of Biomedical Sciences, International Institute of Health Sciences (IIHS), No. 704 Negombo Road, Welisara 71722, Sri Lanka
| | - Madhava Meegaskumbura
- Guangxi Key Laboratory for Forest Ecology and Conservation, College of Forestry, Guangxi University, Nanning 530000, China; (D.S.)
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5
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Cooke SJ, Madliger CL, Lennox RJ, Olden JD, Eliason EJ, Cramp RL, Fuller A, Franklin CE, Seebacher F. Biological mechanisms matter in contemporary wildlife conservation. iScience 2023; 26:106192. [PMID: 36895647 PMCID: PMC9988666 DOI: 10.1016/j.isci.2023.106192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023] Open
Abstract
Given limited resources for wildlife conservation paired with an urgency to halt declines and rebuild populations, it is imperative that management actions are tactical and effective. Mechanisms are about how a system works and can inform threat identification and mitigation such that conservation actions that work can be identified. Here, we call for a more mechanistic approach to wildlife conservation and management where behavioral and physiological tools and knowledge are used to characterize drivers of decline, identify environmental thresholds, reveal strategies that would restore populations, and prioritize conservation actions. With a growing toolbox for doing mechanistic conservation research as well as a suite of decision-support tools (e.g., mechanistic models), the time is now to fully embrace the concept that mechanisms matter in conservation ensuring that management actions are tactical and focus on actions that have the potential to directly benefit and restore wildlife populations.
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Affiliation(s)
- Steven J. Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, 1125 Colonel By Dr., Ottawa, ON K1S 5B6, Canada
- Corresponding author
| | - Christine L. Madliger
- Department of Biology, Algoma University, 1520 Queen St. East, Sault Ste. Marie, ON P6A 2G4, Canada
| | - Robert J. Lennox
- Norwegian Research Centre (NORCE), Laboratory for Freshwater Ecology and Inland Fisheries, 5008 Bergen, Norway
| | - Julian D. Olden
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195-5020, USA
| | - Erika J. Eliason
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Rebecca L. Cramp
- School of Biological Sciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Andrea Fuller
- Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa
| | - Craig E. Franklin
- School of Biological Sciences, University of Queensland, Brisbane, QLD 4072, Australia
| | - Frank Seebacher
- School of Life and Environmental Sciences A08, University of Sydney, Sydney, NSW 2006, Australia
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6
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Ghose SL, Yap TA, Byrne AQ, Sulaeman H, Rosenblum EB, Chan-Alvarado A, Chaukulkar S, Greenbaum E, Koo MS, Kouete MT, Lutz K, McAloose D, Moyer AJ, Parra E, Portik DM, Rockney H, Zink AG, Blackburn DC, Vredenburg VT. Continent-wide recent emergence of a global pathogen in African amphibians. FRONTIERS IN CONSERVATION SCIENCE 2023. [DOI: 10.3389/fcosc.2023.1069490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023] Open
Abstract
IntroductionEmerging infectious diseases are increasingly recognized as a global threat to wildlife. Pandemics in amphibians, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), have resulted in biodiversity loss at a global scale. Genomic data suggest a complex evolutionary history of Bd lineages that vary in pathogenicity. Africa harbors a significant proportion of global amphibian biodiversity, and multiple Bd lineages are known to occur there; yet, despite the decline of many host species, there are currently no described Bd-epizootics. Here, we describe the historical and recent biogeographical spread of Bd and assess its risk to amphibians across the continent of Africa.MethodsWe provide a 165-year view of host-pathogen interactions by (i) employing a Bd assay to test 4,623 specimens (collected 1908–2013); (ii) compiling 12,297 published Bd records (collected 1852–2017); (iii) comparing the frequency of Bd-infected amphibians through time by both country and region; (iv) genotyping Bd lineages; (v) histologically identifying evidence of chytridiomycosis, and (vi) using a habitat suitability model to assess future Bd risk.ResultsWe found a pattern of Bd emergence beginning largely at the turn of the century. From 1852–1999, we found low Bd prevalence (3.2% overall) and limited geographic spread, but after 2000 we documented a sharp increase in prevalence (18.7% overall), wider geographic spread, and multiple Bd lineages that may be responsible for emergence in different regions. We found that Bd risk to amphibians was highest in much of eastern, central, and western Africa.DiscussionOur study documents a largely overlooked yet significant increase in a fungal pathogen that could pose a threat to amphibians across an entire continent. We emphasize the need to bridge historical and contemporary datasets to better describe and predict host-pathogen dynamics over larger temporal scales.
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7
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Lambertini C, Ernetti JR, Missassi AFR, Jorge RF, da Silva Leite D, Lima AP, Toledo LF. Chytrid fungus in amphibians from the lowland Brazilian Amazon. DISEASES OF AQUATIC ORGANISMS 2022; 152:115-125. [PMID: 36519683 DOI: 10.3354/dao03709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Infectious diseases are one of the main threats to biodiversity. The fungus Batrachochytrium dendrobatidis (Bd) is associated with several amphibian losses around the globe, and environmental conditions may dictate the success of pathogen spread. The Brazilian Amazon has been considered climatically unsuitable for chytrid fungus, but additional information on Bd dynamics in this ecoregion is still lacking. We sampled 462 amphibians (449 anurans, 4 caudatans and 9 caecilians), representing 57 species from the Brazilian Amazon, and quantified Bd infections using qPCR. We tested whether abiotic variables predicted the risk of Bd infections, and tested for relationships between biotic variables and Bd. Finally, we experimentally tested the effects of Bd strains CLFT 156 and CLFT 102 (from the southern and northern Atlantic Forest, respectively) on Atelopus manauensis. We detected higher Bd prevalence than those previously reported for the Brazilian Amazon, and positive individuals in all 3 orders of amphibians sampled. Both biotic and abiotic predictors were related to prevalence, and no variable explained infection load. Moreover, we detected higher Bd prevalence in forested than open areas, while the host's reproductive biology was not a factor. We detected higher mortality in the experimental group infected with CLFT 156, probably because this strain was isolated from a region characterized by discrepant climatic conditions (latitudinally more distant) when compared with the host's sampling site in Amazon. The lowland Brazilian Amazon is still underexplored and future studies targeting all amphibian orders are essential to better understand Bd infection dynamics in this region.
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Affiliation(s)
- Carolina Lambertini
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo 13083-862, Brazil
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8
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Moubarak M, Fischhoff IR, Han BA, Castellanos AA. A spatially explicit risk assessment of salamander populations to
Batrachochytrium salamandrivorans
in the United States. DIVERS DISTRIB 2022. [DOI: 10.1111/ddi.13627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
| | | | - Barbara A. Han
- Cary Institute of Ecosystem Studies Millbrook New York USA
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9
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Sopniewski J, Scheele BC, Cardillo M. Predicting the distribution of Australian frogs and their overlap with
Batrachochytrium dendrobatidis
under climate change. DIVERS DISTRIB 2022. [DOI: 10.1111/ddi.13533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
- Jarrod Sopniewski
- Macroevolution & Macroecology Research School of Biology The Australian National University Canberra Australian Capital Territory Australia
- School of Biological Sciences The University of Western Australia Crawley Western Australia Australia
| | - Benjamin C. Scheele
- Macroevolution & Macroecology Research School of Biology The Australian National University Canberra Australian Capital Territory Australia
- Fenner School of Environment and Society The Australian National University Canberra Australian Capital Territory Australia
| | - Marcel Cardillo
- Macroevolution & Macroecology Research School of Biology The Australian National University Canberra Australian Capital Territory Australia
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Pittiglio C, Shadomy S, El Idrissi A, Soumare B, Lubroth J, Makonnen Y. Seasonality and Ecological Suitability Modelling for Anthrax (Bacillus anthracis) in Western Africa. Animals (Basel) 2022; 12:ani12091146. [PMID: 35565571 PMCID: PMC9105891 DOI: 10.3390/ani12091146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/23/2022] [Accepted: 04/24/2022] [Indexed: 02/04/2023] Open
Abstract
Simple Summary Anthrax is a globally distributed, neglected, underreported, soil-borne zoonotic disease. In West Africa, the disease is hyper-endemic, severely affecting the livestock sector. Many challenges exist to control the disease in this region, particularly constraints on financial and human resources. Therefore, methods that can be utilized to improve reporting, guide and prioritize surveillance and control activities and rationalize the allocation of limited resources are crucial. In this study, we showed how to optimize the use of fragmented, heterogeneous and limited precise reporting data of anthrax in Burkina Faso, Ghana, Togo, Benin and Niger to understand risk periods as well as identify and predict risk areas. To achieve this, we used anthrax data from different databases in combination with environmental and climate variables and geospatial remote sensing techniques. Our study demonstrated that the number of anthrax outbreaks by month increase with the increasing monthly rates of change in precipitation and normalized difference vegetation index (NDVI) during the transition period from the dry to the wet season. Livestock density, precipitation, NDVI and alkaline soils were the main predictors of anthrax suitability in the region. Our findings on anthrax seasonality and ecological suitability can inform surveillance, prevention and control programs undertaken by animal and public health authorities and enhance collaborative One Health strategies. Abstract Anthrax is hyper-endemic in West Africa affecting wildlife, livestock and humans. Prediction is difficult due to the lack of accurate outbreak data. However, predicting the risk of infection is important for public health, wildlife conservation and livestock economies. In this study, the seasonality of anthrax outbreaks in West Africa was investigated using climate time series and ecological niche modeling to identify environmental factors related to anthrax occurrence, develop geospatial risk maps and identify seasonal patterns. Outbreak data in livestock, wildlife and humans between 2010 and 2018 were compiled from different sources and analyzed against monthly rates of change in precipitation, normalized difference vegetation index (NDVI) and land surface temperature. Maximum Entropy was used to predict and map the environmental suitability of anthrax occurrence. The findings showed that: (i) Anthrax outbreaks significantly (99%) increased with incremental changes in monthly precipitation and vegetation growth and decremental changes in monthly temperature during January–June. This explains the occurrence of the anthrax peak during the early wet season in West Africa. (ii) Livestock density, precipitation seasonality, NDVI and alkaline soils were the main predictors of anthrax suitability. (iii) Our approach optimized the use of limited and heterogeneous datasets and ecological niche modeling, demonstrating the value of integrated disease notification data and outbreak reports to generate risk maps. Our findings can inform public, animal and environmental health and enhance national and regional One Health disease control strategies.
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Affiliation(s)
- Claudia Pittiglio
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Viale delle Terme di Caracalla, 00153 Rome, Italy;
- Correspondence:
| | - Sean Shadomy
- Food and Agriculture Organization of the United Nations, Joint FAO/WHO Centre (CODEX Food Standards and Zoonotic Diseases), Viale delle Terme di Caracalla, 00153 Rome, Italy; (S.S.); (A.E.I.)
- U.S. Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, 1600 Clifton Rd NE, Mailstop H16-5, Atlanta, GA 30333, USA
| | - Ahmed El Idrissi
- Food and Agriculture Organization of the United Nations, Joint FAO/WHO Centre (CODEX Food Standards and Zoonotic Diseases), Viale delle Terme di Caracalla, 00153 Rome, Italy; (S.S.); (A.E.I.)
| | - Baba Soumare
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Viale delle Terme di Caracalla, 00153 Rome, Italy;
| | - Juan Lubroth
- One Health Consultancies, 00153 Rome, Lazio, Italy;
| | - Yilma Makonnen
- Food and Agriculture Organization of the United Nations, Sub-Regional Office for Eastern Africa (SFE), CMC Road, Bole Sub City, Kebele 12/13, Addis Ababa P.O. Box 5536, Ethiopia;
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11
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Thakur KK, Bhat P, Kumar A, Ravikanth G, Saikia P. Distribution mapping of Bauhinia vahlii Wight & Arn. in India using ecological niche modelling. Trop Ecol 2022. [DOI: 10.1007/s42965-021-00197-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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12
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Alvarado-Rybak M, Lepe-Lopez M, Peñafiel-Ricaurte A, Valenzuela-Sánchez A, Valdivia C, Mardones FO, Bacigalupe LD, Puschendorf R, Cunningham AA, Azat C. Bioclimatic and anthropogenic variables shape the occurrence of Batrachochytrium dendrobatidis over a large latitudinal gradient. Sci Rep 2021; 11:17383. [PMID: 34462470 PMCID: PMC8405646 DOI: 10.1038/s41598-021-96535-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 08/05/2021] [Indexed: 02/07/2023] Open
Abstract
Amphibian chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), has caused the greatest known loss of biodiversity due to an infectious disease. We used Bd infection data from quantitative real-time PCR (qPCR) assays of amphibian skin swabs collected across Chile during 2008-2018 to model Bd occurrence with the aim to determine bioclimatic and anthropogenic variables associated with Bd infection. Also, we used Bd presence/absence records to identify geographical Bd high-risk areas and compare Bd prevalence and infection loads between amphibian families, ecoregions, and host ecology. Data comprised 4155 Bd-specific qPCR assays from 162 locations across a latitudinal gradient of 3700 km (18º to 51ºS). Results showed a significant clustering of Bd associated with urban centres and anthropogenically highly disturbed ecosystems in central-south Chile. Both Bd prevalence and Bd infection loads were higher in aquatic than terrestrial amphibian species. Our model indicated positive associations of Bd prevalence with altitude, temperature, precipitation and human-modified landscapes. Also, we found that macroscale drivers, such as land use change and climate, shape the occurrence of Bd at the landscape level. Our study provides with new evidence that can improve the effectiveness of strategies to mitigate biodiversity loss due to amphibian chytridiomycosis.
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Affiliation(s)
- Mario Alvarado-Rybak
- Sustainability Research Centre & PhD Programme in Conservation Medicine, Life Sciences Faculty, Universidad Andres Bello, Republica 252, Santiago, Chile
- Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK
- Núcleo de Ciencias Aplicadas en Ciencias Veterinarias y Agronómicas, Universidad de las Américas, Echaurren 140, Santiago, Chile
| | - Manuel Lepe-Lopez
- Sustainability Research Centre & PhD Programme in Conservation Medicine, Life Sciences Faculty, Universidad Andres Bello, Republica 252, Santiago, Chile
| | - Alexandra Peñafiel-Ricaurte
- Sustainability Research Centre & PhD Programme in Conservation Medicine, Life Sciences Faculty, Universidad Andres Bello, Republica 252, Santiago, Chile
- Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK
| | - Andrés Valenzuela-Sánchez
- Sustainability Research Centre & PhD Programme in Conservation Medicine, Life Sciences Faculty, Universidad Andres Bello, Republica 252, Santiago, Chile
- ONG Ranita de Darwin, Nataniel Cox 152, Santiago, Chile
- Instituto de Conservación, Biodiversidad y Territorio, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, 5110566, Valdivia, Chile
| | - Catalina Valdivia
- Sustainability Research Centre & PhD Programme in Conservation Medicine, Life Sciences Faculty, Universidad Andres Bello, Republica 252, Santiago, Chile
| | - Fernando O Mardones
- Escuela de Medicina Veterinaria, Facultad de Agronomía e Ingeniería Forestal, Facultad de Ciencias Biológicas y Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Leonardo D Bacigalupe
- Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile
| | - Robert Puschendorf
- School of Biological and Marine Sciences, University of Plymouth, Plymouth, PL4 8AA, UK
| | - Andrew A Cunningham
- Institute of Zoology, Zoological Society of London, Regent's Park, London, NW1 4RY, UK
| | - Claudio Azat
- Sustainability Research Centre & PhD Programme in Conservation Medicine, Life Sciences Faculty, Universidad Andres Bello, Republica 252, Santiago, Chile.
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13
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Scheele BC, Hollanders M, Hoffmann EP, Newell DA, Lindenmayer DB, McFadden M, Gilbert DJ, Grogan LF. Conservation translocations for amphibian species threatened by chytrid fungus: A review, conceptual framework, and recommendations. CONSERVATION SCIENCE AND PRACTICE 2021. [DOI: 10.1111/csp2.524] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Ben C. Scheele
- Fenner School of Environment and Society Australian National University Canberra Australian Capital Territory Australia
| | - Matthijs Hollanders
- Faculty of Science and Engineering Southern Cross University Lismore New South Wales Australia
| | - Emily P. Hoffmann
- Fenner School of Environment and Society Australian National University Canberra Australian Capital Territory Australia
- School of Biological Sciences The University of Western Australia Crawley Western Australia Australia
| | - David A. Newell
- Faculty of Science and Engineering Southern Cross University Lismore New South Wales Australia
| | - David B. Lindenmayer
- Fenner School of Environment and Society Australian National University Canberra Australian Capital Territory Australia
| | - Michael McFadden
- Taronga Conservation Society Australia Mosman New South Wales Australia
| | - Deon J. Gilbert
- Wildlife Conservation and Science Zoos Victoria Parkville Victoria Australia
| | - Laura F. Grogan
- Centre for Planetary Health and Food Security, School of Environment and Science Griffith University Southport Queensland Australia
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14
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Olson DH, Ronnenberg KL, Glidden CK, Christiansen KR, Blaustein AR. Global Patterns of the Fungal Pathogen Batrachochytrium dendrobatidis Support Conservation Urgency. Front Vet Sci 2021; 8:685877. [PMID: 34336978 PMCID: PMC8322974 DOI: 10.3389/fvets.2021.685877] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 06/15/2021] [Indexed: 12/21/2022] Open
Abstract
The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) is a skin pathogen that can cause the emerging infectious disease chytridiomycosis in susceptible species. It has been considered one of the most severe threats to amphibian biodiversity. We aimed to provide an updated compilation of global Bd occurrences by host taxon and geography, and with the larger global Bd dataset we reanalyzed Bd associations with environmental metrics at the world and regional scales. We also compared our Bd data compilation with a recent independent assessment to provide a more comprehensive count of species and countries with Bd occurrences. Bd has been detected in 1,375 of 2,525 (55%) species sampled, more than doubling known species infections since 2013. Bd occurrence is known from 93 of 134 (69%) countries at this writing; this compares to known occurrences in 56 of 82 (68%) countries in 2013. Climate-niche space is highly associated with Bd detection, with different climate metrics emerging as key predictors of Bd occurrence at regional scales; this warrants further assessment relative to climate-change projections. The accretion of Bd occurrence reports points to the common aims of worldwide investigators to understand the conservation concerns for amphibian biodiversity in the face of potential disease threat. Renewed calls for better mitigation of amphibian disease threats resonate across continents with amphibians, especially outside Asia. As Bd appears to be able to infect about half of amphibian taxa and sites, there is considerable room for biosecurity actions to forestall its spread using both bottom-up community-run efforts and top-down national-to-international policies. Conservation safeguards for sensitive species and biodiversity refugia are continuing priorities.
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Affiliation(s)
- Deanna H Olson
- Pacific Northwest Research Station, United States Department of Agriculture (USDA) Forest Service, Corvallis, OR, United States
| | - Kathryn L Ronnenberg
- Pacific Northwest Research Station, United States Department of Agriculture (USDA) Forest Service, Corvallis, OR, United States
| | | | - Kelly R Christiansen
- Pacific Northwest Research Station, United States Department of Agriculture (USDA) Forest Service, Corvallis, OR, United States
| | - Andrew R Blaustein
- Department of Integrative Biology, Oregon State University, Corvallis, OR, United States
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15
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Beukema W, Erens J, Schulz V, Stegen G, Spitzen-van der Sluijs A, Stark T, Laudelout A, Kinet T, Kirschey T, Poulain M, Miaud C, Steinfartz S, Martel A, Pasmans F. Landscape epidemiology of Batrachochytrium salamandrivorans: reconciling data limitations and conservation urgency. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02342. [PMID: 33817953 DOI: 10.1002/eap.2342] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 12/01/2020] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
Starting in 2010, rapid fire salamander (Salamandra salamandra) population declines in northwestern Europe heralded the emergence of Batrachochytrium salamandrivorans (Bsal), a salamander-pathogenic chytrid fungus. Bsal poses an imminent threat to global salamander diversity owing to its wide host range, high pathogenicity, and long-term persistence in ecosystems. While there is a pressing need to develop further research and conservation actions, data limitations inherent to recent pathogen emergence obscure necessary insights into Bsal disease ecology. Here, we use a hierarchical modeling framework to describe Bsal landscape epidemiology of outbreak sites in light of these methodological challenges. Using model selection and machine learning, we find that Bsal presence is associated with humid and relatively cool, stable climates. Outbreaks are generally located in areas characterized by low landscape heterogeneity and low steepness of slope. We further find an association between Bsal presence and high trail density, suggesting that human-mediated spread may increase risk for spillover between populations. We then use distribution modeling to show that favorable conditions occur in lowlands influenced by the North Sea, where increased survey effort is needed to determine how Bsal impacts local newt populations, but also in hill- and mountain ranges in northeastern France and the lower half of Germany. Finally, connectivity analyses suggest that these hill- and mountain ranges may act as stepping stones for further spread southward. Our results provide initial insight into regional environmental conditions underlying Bsal epizootics, present updated invasibility predictions for northwestern Europe, and lead us to discuss a wide variety of potential survey and research actions needed to advance future conservation and mitigation efforts.
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Affiliation(s)
- Wouter Beukema
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
- Naturalis Biodiversity Center, P.O. Box␣9517, Leiden, 2300RA, the Netherlands
| | - Jesse Erens
- Naturalis Biodiversity Center, P.O. Box␣9517, Leiden, 2300RA, the Netherlands
| | - Vanessa Schulz
- Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, Talstrasse 33, Leipzig, 04103, Germany
- Technische Universität Braunschweig, Division of Evolutionary Biology, Zoological Institute, Mendelssohnstrasse 4, Braunschweig, 38106, Germany
| | - Gwij Stegen
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | | | - Tariq Stark
- Reptile, Amphibian & Fish Conservation Netherlands (RAVON), Toernooiveld 1, Nijmegen, 6525ED, the Netherlands
| | - Arnaud Laudelout
- Reptile, Amphibian & Fish Conservation Netherlands (RAVON), Toernooiveld 1, Nijmegen, 6525ED, the Netherlands
| | - Thierry Kinet
- Natagora, Traverse des Muses 1, Namur, 5000, Belgium
| | - Tom Kirschey
- Nature and Biodiversity Conservation Union (NABU), Charitéstrasse 3, Berlin, 10117, Germany
| | - Marie Poulain
- Biogeography and Vertebrate Ecology, CEFE, EPHE-PSL, CNRS, University of Montpellier, Paul Valéry University Montpellier III, 1919 route de Mende, Montpellier, 34293, France
| | - Claude Miaud
- Biogeography and Vertebrate Ecology, CEFE, EPHE-PSL, CNRS, University of Montpellier, Paul Valéry University Montpellier III, 1919 route de Mende, Montpellier, 34293, France
| | - Sebastian Steinfartz
- Molecular Evolution and Systematics of Animals, Institute of Biology, University of Leipzig, Talstrasse 33, Leipzig, 04103, Germany
| | - An Martel
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
| | - Frank Pasmans
- Wildlife Health Ghent, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, Merelbeke, 9820, Belgium
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16
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Huang YH, Joel H, Küsters M, Barandongo ZR, Cloete CC, Hartmann A, Kamath PL, Kilian JW, Mfune JKE, Shatumbu G, Zidon R, Getz WM, Turner WC. Disease or drought: environmental fluctuations release zebra from a potential pathogen-triggered ecological trap. Proc Biol Sci 2021; 288:20210582. [PMID: 34074118 PMCID: PMC8170208 DOI: 10.1098/rspb.2021.0582] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 05/10/2021] [Indexed: 12/02/2022] Open
Abstract
When a transmission hotspot for an environmentally persistent pathogen establishes in otherwise high-quality habitat, the disease may exert a strong impact on a host population. However, fluctuating environmental conditions lead to heterogeneity in habitat quality and animal habitat preference, which may interrupt the overlap between selected and risky habitats. We evaluated spatio-temporal patterns in anthrax mortalities in a plains zebra (Equus quagga) population in Etosha National Park, Namibia, incorporating remote-sensing and host telemetry data. A higher proportion of anthrax mortalities of herbivores was detected in open habitats than in other habitat types. Resource selection functions showed that the zebra population shifted habitat selection in response to changes in rainfall and vegetation productivity. Average to high rainfall years supported larger anthrax outbreaks, with animals congregating in preferred open habitats, while a severe drought forced animals into otherwise less preferred habitats, leading to few anthrax mortalities. Thus, the timing of anthrax outbreaks was congruent with preference for open plains habitats and a corresponding increase in pathogen exposure. Given shifts in habitat preference, the overlap in high-quality habitat and high-risk habitat is intermittent, reducing the adverse consequences for the population.
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Affiliation(s)
- Yen-Hua Huang
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Hendrina Joel
- Department of Biological Sciences, University of Namibia, Windhoek, Namibia
| | | | - Zoe R. Barandongo
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA
| | - Claudine C. Cloete
- Etosha Ecological Institute, Ministry of Environment, Forestry and Tourism, Okaukuejo, Namibia
| | - Axel Hartmann
- Etosha Ecological Institute, Ministry of Environment, Forestry and Tourism, Okaukuejo, Namibia
| | - Pauline L. Kamath
- School of Food and Agriculture, University of Maine, Orono, ME 04469, USA
| | - J. Werner Kilian
- Etosha Ecological Institute, Ministry of Environment, Forestry and Tourism, Okaukuejo, Namibia
| | - John K. E. Mfune
- Department of Biological Sciences, University of Namibia, Windhoek, Namibia
| | - Gabriel Shatumbu
- Etosha Ecological Institute, Ministry of Environment, Forestry and Tourism, Okaukuejo, Namibia
| | - Royi Zidon
- Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Wayne M. Getz
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94704, USA
- School of Mathematical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Wendy C. Turner
- US Geological Survey, Wisconsin Cooperative Wildlife Research Unit, Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA
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17
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HIGHER INFECTION PREVALENCE IN AMPHIBIANS INHABITING HUMAN-MADE COMPARED TO NATURAL WETLANDS. J Wildl Dis 2021; 56:823-836. [PMID: 33600598 DOI: 10.7589/2019-09-220] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 02/21/2020] [Indexed: 11/20/2022]
Abstract
It is unclear how suitable human-made wetlands are for supporting wildlife and how they impact wildlife disease risk. Natural wetlands (those that were created without human actions) can support more diverse and resilient communities that are at lower risk of disease outbreaks. We compared frog community composition and infection with the pathogenic fungus Batrachochytrium dendrobatidis (Bd) between human-made and natural wetlands in Tippecanoe County, Indiana, US. We conducted visual encounter surveys of frog communities and quantified Bd infection prevalence at four natural and five human-made wetlands. Water parameters associated with human practices (e.g., pH, salinity) and surrounding land use were also compared across sites. We found higher Bd infection prevalence at human-made sites than at natural sites, with monthly differences showing highest infection in spring and fall, and decreasing infection with increasing water temperature. However, we found no differences between human-made and natural sites regarding amphibian community composition, water quality, or surrounding land use. Further, we found frog density increased with distance to nearest roads among both human-made and natural sites. These findings might suggest that human-made wetlands can support frog communities similar to natural wetlands, but pose a greater risk of Bd infection.
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18
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Bie J, Zheng K, Gao X, Liu B, Ma J, Hayat MA, Xiao J, Wang H. Spatial Risk Analysis of Batrachochytrium dendrobatidis, A Global Emerging Fungal Pathogen. ECOHEALTH 2021; 18:3-12. [PMID: 34212260 DOI: 10.1007/s10393-021-01519-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 01/21/2021] [Accepted: 03/02/2021] [Indexed: 06/13/2023]
Abstract
Chytridiomycosis, a leading cause for the global decline in the number of amphibians, is caused by the fungal pathogen Batrachochytrium dendrobatidis. In this study, global distribution data of B. dendrobatidis were collected from January 2009 to May 2019. Space-time scan statistics and the maximum entropy (MaxEnt) model were used to analyze the epidemic trends and aggregation of the pathogen, and predict B. dendrobatidis distribution through its relationships with climate factors, wind speed, and solar radiation. The results of space-time scan statistics show seven clusters of data for the distribution of B. dendrobatidis. The time was mainly concentrated in 2009, 2013, 2015, and 2016, and the regions were primarily concentrated in southeastern Canada, southwestern France, Nigeria, Cameroon, eastern Brazil, southeastern Brazil, central Madagascar, and central and eastern Australia. MaxEnt showed that annual precipitation had the largest contribution percentage in the model, and annual mean temperature highly influenced the distribution of B. dendrobatidis. The global high-risk areas of B. dendrobatidis distribution were mainly observed in western Canada, southern Brazil, Chile, the United Kingdom, Japan, the Republic of Korea, eastern South Africa, eastern Madagascar, southeastern Australia, and southern China.
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Affiliation(s)
- Jia Bie
- Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin, 150030, People's Republic of China
| | - Keren Zheng
- Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin, 150030, People's Republic of China
| | - Xiang Gao
- Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin, 150030, People's Republic of China
| | - Boyang Liu
- Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin, 150030, People's Republic of China
| | - Jun Ma
- Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin, 150030, People's Republic of China
| | - Muhammad Abid Hayat
- Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin, 150030, People's Republic of China
| | - Jianhua Xiao
- Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin, 150030, People's Republic of China
| | - Hongbin Wang
- Heilongjiang Key Laboratory for Laboratory Animals and Comparative Medicine, College of Veterinary Medicine, Northeast Agricultural University, 600 Changjiang Road, Harbin, 150030, People's Republic of China.
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19
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Rahman MM, Jahan H, Rabbe MF, Chakraborty M, Salauddin M. First Detection of Batrachochytrium dendrobatidis in Wild Frogs from Bangladesh. ECOHEALTH 2021; 18:31-43. [PMID: 34028636 DOI: 10.1007/s10393-021-01522-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 02/25/2021] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
Global amphibian populations are facing a novel threat, chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), which is responsible for the severe decline of a number of species across several continents. Chytridiomycosis in Asia is a relatively recent discovery yet there have been no reports on Bd-presence in Bangladeshi amphibians. We conducted a preliminary study on 133 wild frogs from seven sites in Bangladesh between April and July 2018. Nested PCR analysis showed 20 samples (15.04%) and 50% of the tested taxa (9 species from 6 genera and 4 families) as Bd-positive. Eight of the nine species are discovered as newly infected hosts. Analysis of Bd-positive samples shows prevalence does not significantly vary among different land cover categories, although the occurrence is higher in forested areas. The prevalence rate is similar in high and low disturbed areas, but the range of occurrence is statistically higher in low disturbance areas. Maximum entropy distribution modeling indicates high probabilities of Bd occurrence in hilly and forested areas in southeast and central-north Bangladesh. The Bd-specific ITS1-5.8S-ITS2 ribosomal gene sequence from the Bd-positive samples tested is completely identical. A neighbor-joining phylogenetic tree reveals that the identified strain shares a common ancestry with strains previously discovered in different Asian regions. Our results provide the first evidence of Bd-presence in Bangladeshi amphibians, inferring that diversity is at risk. The effects of environmental and climatic factors along with quantitative PCR analysis are required to determine the infection intensity and susceptibility of amphibians in the country.
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Affiliation(s)
- Md Mokhlesur Rahman
- Department of Zoology, University of Dhaka, Dhaka, 1000, Bangladesh.
- Department of Anthropology, Durham University, South Road, Durham, DH1 3LE, UK.
| | - Hawa Jahan
- Department of Zoology, University of Dhaka, Dhaka, 1000, Bangladesh
- Division of Evolution and Genomic Sciences, FBMH, School of Biological Sciences, University of Manchester, Oxford Rd, Manchester, M13 9PT, UK
| | - Md Fazle Rabbe
- Department of Zoology, University of Dhaka, Dhaka, 1000, Bangladesh
| | | | - Md Salauddin
- Department of Geography and Environment, Jagannath University, Dhaka, 1100, Bangladesh
- Disaster Risk Management Department, Bangladesh Red Crescent Society, Red Crescent Sarak, Bara Moghbazar, Dhaka, 1217, Bangladesh
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20
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Winter is coming-Temperature affects immune defenses and susceptibility to Batrachochytrium salamandrivorans. PLoS Pathog 2021; 17:e1009234. [PMID: 33600433 PMCID: PMC7891748 DOI: 10.1371/journal.ppat.1009234] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 12/08/2020] [Indexed: 12/24/2022] Open
Abstract
Environmental temperature is a key factor driving various biological processes, including immune defenses and host-pathogen interactions. Here, we evaluated the effects of environmental temperature on the pathogenicity of the emerging fungal pathogen, Batrachochytrium salamandrivorans (Bsal), using controlled laboratory experiments, and measured components of host immune defense to identify regulating mechanisms. We found that adult and juvenile Notophthalmus viridescens died faster due to Bsal chytridiomycosis at 14°C than at 6 and 22°C. Pathogen replication rates, total available proteins on the skin, and microbiome composition likely drove these relationships. Temperature-dependent skin microbiome composition in our laboratory experiments matched seasonal trends in wild N. viridescens, adding validity to these results. We also found that hydrophobic peptide production after two months post-exposure to Bsal was reduced in infected animals compared to controls, perhaps due to peptide release earlier in infection or impaired granular gland function in diseased animals. Using our temperature-dependent susceptibility results, we performed a geographic analysis that revealed N. viridescens populations in the northeastern United States and southeastern Canada are at greatest risk for Bsal invasion, which shifted risk north compared to previous assessments. Our results indicate that environmental temperature will play a key role in the epidemiology of Bsal and provide evidence that temperature manipulations may be a viable disease management strategy. In 2010, a new skin-eating fungus, Batrachochytrium salamandrivorans (Bsal), was discovered killing salamanders in the Netherlands. Since then, the pathogen has spread to other European countries. Bsal is believed to be from Asia and is being translocated through the international trade of amphibians. To our knowledge, Bsal has not arrived to North America. As a proactive strategy for disease control, we evaluated how a range of environmental temperatures in North America could affect invasion risk of Bsal into a widely distributed salamander species, the eastern newt (Notophthalmus viridescens). Our results show that northeastern USA, southeastern Canada, and the higher elevations of the Appalachian Mountains have the greatest likelihood of Bsal invasion, when temperature-dependent susceptibility is included in risk analyses. Changes in eastern newt susceptibility to Bsal infection associated with temperature are likely an interaction between pathogen replication rate and host immune defenses, including changes in skin microbiome composition and the host’s ability to produce Bsal-killing proteins on the skin. Our study provides new insights into how latitude, elevation and season can impact the epidemiology of Bsal, and suggests that strategies that manipulate microclimate of newt habitats could be useful in managing Bsal outbreaks and that climate change will impact Bsal invasion probability.
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21
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Crawford-Ash J, Rowley JJL. Bad neighbours: amphibian chytrid fungus Batrachochytrium dendrobatidis infection dynamics in three co-occurring frog species of southern Sydney, Australia. DISEASES OF AQUATIC ORGANISMS 2021; 143:101-108. [PMID: 33570043 DOI: 10.3354/dao03557] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Wildlife disease is a major cause of global biodiversity loss. Amongst the most devastating is the disease chytridiomycosis, caused by the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd). This disease has contributed to declines and extinctions in hundreds of amphibian species, but not all species are affected equally. Some amphibian hosts are capable of carrying high levels of Bd infection without population declines, acting as reservoir species for the pathogen and driving population declines in sympatric species. In Australia, several species have been proposed as reservoir species; however, our understanding of Bd is derived from studies that are highly geographically and taxonomically biased, and our ability to extrapolate from these systems is unknown. We examined the prevalence and intensity of Bd infection in 3 frog species in a previously unstudied host-pathogen system in temperate eastern Australia: the Blue Mountains tree frog Litoria citropa, a poorly-known species predicted to be susceptible to Bd infection; and the common eastern froglet Crinia signifera and the stony creek frog L. lesueuri, which have both been identified as reservoir species in other regions. We found that L. citropa and L. lesueuri were infected with Bd at a high prevalence and often high intensity, while the reverse was true for C. signifera. All species were detected at moderate abundance and there was no evidence of morbidity and mortality. Our findings do not support C. signifera and L. lesueuri being reservoir species in this system, highlighting the importance of region-specific studies to inform conservation management.
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Affiliation(s)
- Jordann Crawford-Ash
- Australian Museum Research Institute, Australian Museum, 1 William St, Sydney, NSW 2010, Australia
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22
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Ocampo-Chavira P, Eaton-Gonzalez R, Riquelme M. Of Mice and Fungi: Coccidioides spp. Distribution Models. J Fungi (Basel) 2020; 6:jof6040320. [PMID: 33261168 PMCID: PMC7712536 DOI: 10.3390/jof6040320] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/18/2020] [Accepted: 11/25/2020] [Indexed: 12/25/2022] Open
Abstract
The continuous increase of Coccidioidomycosis cases requires reliable detection methods of the causal agent, Coccidioides spp., in its natural environment. This has proven challenging because of our limited knowledge on the distribution of this soil-dwelling fungus. Knowing the pathogen’s geographic distribution and its relationship with the environment is crucial to identify potential areas of risk and to prevent disease outbreaks. The maximum entropy (Maxent) algorithm, Geographic Information System (GIS) and bioclimatic variables were combined to obtain current and future potential distribution models (DMs) of Coccidioides and its putative rodent reservoirs for Arizona, California and Baja California. We revealed that Coccidioides DMs constructed with presence records from one state are not well suited to predict distribution in another state, supporting the existence of distinct phylogeographic populations of Coccidioides. A great correlation between Coccidioides DMs and United States counties with high Coccidioidomycosis incidence was found. Remarkably, under future scenarios of climate change and high concentration of greenhouse gases, the probability of habitat suitability for Coccidioides increased. Overlap analysis between the DMs of rodents and Coccidioides, identified Neotoma lepida as one of the predominant co-occurring species in all three states. Considering rodents DMs would allow to implement better surveillance programs to monitor disease spread.
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Affiliation(s)
- Pamela Ocampo-Chavira
- Department of Microbiology, Centro de Investigación Científica y Educación Superior de Ensenada (CICESE), Ctra. Ensenada-Tijuana No. 3918, Ensenada, Baja California 22860, Mexico;
| | - Ricardo Eaton-Gonzalez
- Academic Unit of Ensenada, Universidad Tecnológica de Tijuana, Ctra. a la Bufadora KM. 1, Maneadero Parte Alta, Ensenada, Baja California 22790, Mexico;
| | - Meritxell Riquelme
- Department of Microbiology, Centro de Investigación Científica y Educación Superior de Ensenada (CICESE), Ctra. Ensenada-Tijuana No. 3918, Ensenada, Baja California 22860, Mexico;
- Correspondence:
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23
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Amphibian Infection Risk Changes with Host Life Stage and across a Landscape Gradient. J HERPETOL 2020. [DOI: 10.1670/19-107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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24
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Grogan LF, Humphries JE, Robert J, Lanctôt CM, Nock CJ, Newell DA, McCallum HI. Immunological Aspects of Chytridiomycosis. J Fungi (Basel) 2020; 6:jof6040234. [PMID: 33086692 PMCID: PMC7712659 DOI: 10.3390/jof6040234] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 12/27/2022] Open
Abstract
Amphibians are currently the most threatened vertebrate class, with the disease chytridiomycosis being a major contributor to their global declines. Chytridiomycosis is a frequently fatal skin disease caused by the fungal pathogens Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal). The severity and extent of the impact of the infection caused by these pathogens across modern Amphibia are unprecedented in the history of vertebrate infectious diseases. The immune system of amphibians is thought to be largely similar to that of other jawed vertebrates, such as mammals. However, amphibian hosts are both ectothermic and water-dependent, which are characteristics favouring fungal proliferation. Although amphibians possess robust constitutive host defences, Bd/Bsal replicate within host cells once these defences have been breached. Intracellular fungal localisation may contribute to evasion of the induced innate immune response. Increasing evidence suggests that once the innate defences are surpassed, fungal virulence factors suppress the targeted adaptive immune responses whilst promoting an ineffectual inflammatory cascade, resulting in immunopathology and systemic metabolic disruption. Thus, although infections are contained within the integument, crucial homeostatic processes become compromised, leading to mortality. In this paper, we present an integrated synthesis of amphibian post-metamorphic immunological responses and the corresponding outcomes of infection with Bd, focusing on recent developments within the field and highlighting future directions.
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Affiliation(s)
- Laura F. Grogan
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Southport, QLD 4222, Australia;
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW 2480, Australia; (J.E.H.); (D.A.N.)
- Correspondence:
| | - Josephine E. Humphries
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW 2480, Australia; (J.E.H.); (D.A.N.)
| | - Jacques Robert
- University of Rochester Medical Center, Rochester, NY 14642, USA;
| | - Chantal M. Lanctôt
- Australian Rivers Institute, Griffith University, Southport, QLD 4222, Australia;
| | - Catherine J. Nock
- Southern Cross Plant Science, Southern Cross University, Lismore, NSW 2480, Australia;
| | - David A. Newell
- Forest Research Centre, School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW 2480, Australia; (J.E.H.); (D.A.N.)
| | - Hamish I. McCallum
- Environmental Futures Research Institute and School of Environment and Science, Griffith University, Southport, QLD 4222, Australia;
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25
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Bell SC, Heard GW, Berger L, Skerratt LF. Connectivity over a disease risk gradient enables recovery of rainforest frogs. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2020; 30:e02152. [PMID: 32343856 DOI: 10.1002/eap.2152] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 02/14/2020] [Accepted: 03/30/2020] [Indexed: 06/11/2023]
Abstract
Chytridiomycosis has been a key driver of global frog declines and extinctions, particularly for high-altitude populations across Australia and the Americas. While recent evidence shows some species are recovering, the extent of such recoveries and the mechanisms underpinning them remain poorly resolved. We surveyed the historical latitudinal and elevational range of four Australian rainforest frogs that disappeared from upland sites between 1989 and 1994 to establish their contemporary distribution and elevational limits, and investigate factors affecting population recovery. Five rainforest streams were surveyed from mountain-base to summit (30 sites in total), with swabs collected from the target species (Litoria dayi, L. nannotis, L. rheocola, and L. serrata) to determine their infection status, and data loggers deployed to measure microclimatic variation across the elevational gradient. Infection probability increased with elevation and canopy cover as it was tightly and inversely correlated with stream-side air temperature. Occupancy patterns suggest varying responses to this disease threat gradient. Two species, L. rheocola and L. serrata, were found over their full historical elevational range (≥1,000 m above sea level [asl]), while L. dayi was not detected above 400 m (formerly known up to 900 m asl) and L. nannotis was not detected above 800 m (formerly known up to 1,200 m asl). Site occupancy probability was negatively related to predicted infection prevalence for L. dayi, L. nannotis, and L. rheocola, but not L. serrata, which appears to now tolerate high fungal burdens. This study highlights the importance of environmental refuges and connectivity across disease risk gradients for the persistence and natural recovery of frogs susceptible to chytridiomycosis. Likewise, in documenting both interspecific variation in recovery rates and intraspecific differences between sites, this study suggests interactions between disease threats and host selection exist that could be manipulated. For example, translocations may be warranted where connectivity is poor or the increase in disease risk is too steep to allow recolonization, combined with assisted selection or use of founders from populations that have already undergone natural selection.
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Affiliation(s)
- Sara C Bell
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, 4811, Australia
- One Health Research Group, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Victoria, 3030, Australia
| | - Geoffrey W Heard
- Institute of Land, Water and Society, Charles Sturt University, Albury, New South Wales, 2640, Australia
- Victorian Department of Environment, Land, Water and Planning, Arthur Rylah Institute for Environmental Research, Heidelberg, Victoria, 3084, Australia
| | - Lee Berger
- One Health Research Group, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Victoria, 3030, Australia
| | - Lee F Skerratt
- One Health Research Group, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, Victoria, 3030, Australia
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26
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Jiménez RR, Alvarado G, Sandoval J, Sommer S. Habitat disturbance influences the skin microbiome of a rediscovered neotropical-montane frog. BMC Microbiol 2020; 20:292. [PMID: 32962670 PMCID: PMC7509932 DOI: 10.1186/s12866-020-01979-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 09/15/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND The skin microbiome serves as a first line defense against pathogens in vertebrates. In amphibians, it has the potential to protect against the chytrid fungus Batrachochytrium dendrobatis (Bd), a likely agent of amphibian declines. Alteration of the microbiome associated with unfavorable environmental changes produced by anthropogenic activities may make the host more susceptible to pathogens. Some amphibian species that were thought to be "extinct" have been rediscovered years after population declines in the late 1980s probably due to evolved Bd-resistance and are now threatened by anthropogenic land-use changes. Understanding the effects of habitat disturbance on the host skin microbiome is relevant for understanding the health of these species, along with its susceptibility to pathogens such as Bd. Here, we investigate the influence of habitat alteration on the skin bacterial communities as well as specifically the putative Bd-inhibitory bacterial communities of the montane frog Lithobates vibicarius. This species, after years of not being observed, was rediscovered in small populations inhabiting undisturbed and disturbed landscapes, and with continuous presence of Bd. RESULTS We found that cutaneous bacterial communities of tadpoles and adults differed between undisturbed and disturbed habitats. The adults from disturbed habitats exhibited greater community dispersion than those from undisturbed habitats. We observed a higher richness of putative Bd-inhibitory bacterial strains in adults from disturbed habitats than in those from undisturbed habitats, as well as a greater number of these potential protective bacteria with a high relative abundance. CONCLUSIONS Our findings support the microbial "Anna Karenina principle", in which disturbance is hypothesized to cause greater microbial dispersion in communities, a so-called dysbiosis, which is a response of animal microbiomes to stress factors that decrease the ability of the host or its microbiome to regulate community composition. On the positive side, the high richness and relative abundance of putative Bd-inhibitory bacteria may indicate the development of a defense mechanism that enhances Bd-protection, attributed to a co-occurrence of more than 30-years of host and pathogen in these disturbed habitats. Our results provide important insight into the influence of human-modified landscapes on the skin microbiome and health implications of Bd-survivor species.
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Affiliation(s)
- Randall R Jiménez
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Albert-Einstein Allee 11, 89069, Ulm, Germany.
| | - Gilbert Alvarado
- Laboratory of Comparative Wildlife Pathology, School of Veterinary Medicine and Animal Sciences, University of São Paulo, Av. Orlando Marques de Paiva 87, São Paulo, Brazil
- Laboratory of Experimental and Comparative Pathology (LAPECOM), Biology School, University of Costa Rica, San José, Costa Rica
| | - José Sandoval
- Laboratory of Experimental and Comparative Pathology (LAPECOM), Biology School, University of Costa Rica, San José, Costa Rica
| | - Simone Sommer
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Albert-Einstein Allee 11, 89069, Ulm, Germany
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27
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Castro Monzon F, Rödel MO, Jeschke JM. Tracking Batrachochytrium dendrobatidis Infection Across the Globe. ECOHEALTH 2020; 17:270-279. [PMID: 33201333 PMCID: PMC7719156 DOI: 10.1007/s10393-020-01504-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 09/21/2020] [Accepted: 09/21/2020] [Indexed: 05/17/2023]
Abstract
Infection records of Batrachochytrium dendrobatidis (Bd), a pathogen that has devastated amphibian populations worldwide, have rapidly increased since the pathogen's discovery. Dealing with so many records makes it difficult to (a) know where, when and in which species infections have been detected, (b) understand how widespread and pervasive Bd is and (c) prioritize study and management areas. We conducted a systematic review of papers and compiled a database with Bd infection records. Our dataset covers 71 amphibian families and 119 countries. The data revealed how widespread and adaptable Bd is, being able to infect over 50% of all tested amphibian species, with over 1000 confirmed host species and being present in 86 countries. The distribution of infected species is uneven among and within countries. Areas where the distributions of many infected species overlap are readily visible; these are regions where Bd likely develops well. Conversely, areas where the distributions of species that tested negative overlap, such as the Atlantic Coast in the USA, suggest the presence of Bd refuges. Finally, we report how the number of tested and infected species has changed through time, and provide a list of oldest detection records per country.
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Affiliation(s)
- Federico Castro Monzon
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Str. 1-3, 14195, Berlin, Germany.
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587, Berlin, Germany.
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, Königin-Luise-Str. 2-4, 14195, Berlin, Germany.
| | - Mark-Oliver Rödel
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, Königin-Luise-Str. 2-4, 14195, Berlin, Germany
- Museum für Naturkunde - Leibniz Institute for Evolution and Biodiversity Science, Invalidenstr. 43, 10115, Berlin, Germany
| | - Jonathan M Jeschke
- Institute of Biology, Freie Universität Berlin, Königin-Luise-Str. 1-3, 14195, Berlin, Germany
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587, Berlin, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research, Königin-Luise-Str. 2-4, 14195, Berlin, Germany
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28
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Rodríguez-Verdugo A, Lozano-Huntelman N, Cruz-Loya M, Savage V, Yeh P. Compounding Effects of Climate Warming and Antibiotic Resistance. iScience 2020; 23:101024. [PMID: 32299057 PMCID: PMC7160571 DOI: 10.1016/j.isci.2020.101024] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/11/2020] [Accepted: 03/25/2020] [Indexed: 12/18/2022] Open
Abstract
Bacteria have evolved diverse mechanisms to survive environments with antibiotics. Temperature is both a key factor that affects the survival of bacteria in the presence of antibiotics and an environmental trait that is drastically increasing due to climate change. Therefore, it is timely and important to understand links between temperature changes and selection of antibiotic resistance. This review examines these links by synthesizing results from laboratories, hospitals, and environmental studies. First, we describe the transient physiological responses to temperature that alter cellular behavior and lead to antibiotic tolerance and persistence. Second, we focus on the link between thermal stress and the evolution and maintenance of antibiotic resistance mutations. Finally, we explore how local and global changes in temperature are associated with increases in antibiotic resistance and its spread. We suggest that a multidisciplinary, multiscale approach is critical to fully understand how temperature changes are contributing to the antibiotic crisis.
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Affiliation(s)
| | - Natalie Lozano-Huntelman
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Mauricio Cruz-Loya
- Department of Computational Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Van Savage
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA; Department of Computational Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA; Santa Fe Institute, Santa Fe, NM 87501, USA
| | - Pamela Yeh
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, Los Angeles, CA 90095, USA; Santa Fe Institute, Santa Fe, NM 87501, USA.
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29
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Farashi A, Alizadeh-Noughani M. Conservation of Pleske's Racerunner (Eremias pleskei) in a Changing Climate. ANN ZOOL FENN 2019. [DOI: 10.5735/086.056.0109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Azita Farashi
- Department of Environmental Sciences, Faculty of Natural Resource and Environment, Ferdowsi University of Mashhad, Iran
| | - Mohammad Alizadeh-Noughani
- Department of Environmental Sciences, Faculty of Natural Resource and Environment, Ferdowsi University of Mashhad, Iran
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30
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Sonn JM, Utz RM, Richards‐Zawacki CL. Effects of latitudinal, seasonal, and daily temperature variations on chytrid fungal infections in a North American frog. Ecosphere 2019. [DOI: 10.1002/ecs2.2892] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Julia M. Sonn
- Department of Ecology and Evolutionary Biology Tulane University New Orleans Louisiana USA
| | - Ryan M. Utz
- Falk School of Sustainability Chatham University Gibsonia Pennsylvania USA
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31
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Bolom‐Huet R, Pineda E, Díaz‐Fleischer F, Muñoz‐Alonso AL, Galindo‐González J. Known and estimated distribution in Mexico of
Batrachochytrium dendrobatidis,
a pathogenic fungus of amphibians. Biotropica 2019. [DOI: 10.1111/btp.12697] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
| | - Eduardo Pineda
- Red de Biología y Conservación de Vertebrados Instituto de Ecología A. C. Xalapa Veracruz México
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32
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Scheele BC, Pasmans F, Skerratt LF, Berger L, Martel A, Beukema W, Acevedo AA, Burrowes PA, Carvalho T, Catenazzi A, De la Riva I, Fisher MC, Flechas SV, Foster CN, Frías-Álvarez P, Garner TWJ, Gratwicke B, Guayasamin JM, Hirschfeld M, Kolby JE, Kosch TA, La Marca E, Lindenmayer DB, Lips KR, Longo AV, Maneyro R, McDonald CA, Mendelson J, Palacios-Rodriguez P, Parra-Olea G, Richards-Zawacki CL, Rödel MO, Rovito SM, Soto-Azat C, Toledo LF, Voyles J, Weldon C, Whitfield SM, Wilkinson M, Zamudio KR, Canessa S. Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity. Science 2019; 363:1459-1463. [PMID: 30923224 DOI: 10.1126/science.aav0379] [Citation(s) in RCA: 537] [Impact Index Per Article: 107.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 02/06/2019] [Indexed: 12/18/2022]
Abstract
Anthropogenic trade and development have broken down dispersal barriers, facilitating the spread of diseases that threaten Earth's biodiversity. We present a global, quantitative assessment of the amphibian chytridiomycosis panzootic, one of the most impactful examples of disease spread, and demonstrate its role in the decline of at least 501 amphibian species over the past half-century, including 90 presumed extinctions. The effects of chytridiomycosis have been greatest in large-bodied, range-restricted anurans in wet climates in the Americas and Australia. Declines peaked in the 1980s, and only 12% of declined species show signs of recovery, whereas 39% are experiencing ongoing decline. There is risk of further chytridiomycosis outbreaks in new areas. The chytridiomycosis panzootic represents the greatest recorded loss of biodiversity attributable to a disease.
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Affiliation(s)
- Ben C Scheele
- Fenner School of Environment and Society, Australian National University, Canberra, ACT 2601, Australia. .,National Environmental Science Programme, Threatened Species Recovery Hub, Canberra, ACT 2601, Australia.,One Health Research Group, Melbourne Veterinary School, The University of Melbourne, Werribee, VIC 3030, Australia
| | - Frank Pasmans
- Wildlife Health Ghent, Department of Pathology, Bacteriology, and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, B-9820 Merelbeke, Belgium
| | - Lee F Skerratt
- One Health Research Group, Melbourne Veterinary School, The University of Melbourne, Werribee, VIC 3030, Australia
| | - Lee Berger
- One Health Research Group, Melbourne Veterinary School, The University of Melbourne, Werribee, VIC 3030, Australia
| | - An Martel
- Wildlife Health Ghent, Department of Pathology, Bacteriology, and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, B-9820 Merelbeke, Belgium
| | - Wouter Beukema
- Wildlife Health Ghent, Department of Pathology, Bacteriology, and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, B-9820 Merelbeke, Belgium
| | - Aldemar A Acevedo
- Programa de Doctorado en Ciencias Biológicas, Laboratorio de Biología Evolutiva, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O'Higgins 340, Santiago, Chile.,Grupo de Investigación en Ecología y Biogeografía, Universidad de Pamplona, Barrio El Buque, Km 1, Vía a Bucaramanga, Pamplona, Colombia
| | - Patricia A Burrowes
- Department of Biology, University of Puerto Rico, P.O. Box 23360, San Juan, Puerto Rico
| | - Tamilie Carvalho
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, Brazil
| | - Alessandro Catenazzi
- Department of Biological Sciences, Florida International University, Miami, FL 33199, USA
| | - Ignacio De la Riva
- Museo Nacional de Ciencias Naturales-CSIC, C/ José Gutiérrez Abascal 2, Madrid 28006, Spain
| | - Matthew C Fisher
- MRC Centre for Global Infectious Disease Analysis, School of Public Health, Imperial College London, London W2 1PG, UK
| | - Sandra V Flechas
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia.,Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Sede Venado de Oro, Paseo Bolívar 16-20, Bogotá, Colombia
| | - Claire N Foster
- Fenner School of Environment and Society, Australian National University, Canberra, ACT 2601, Australia
| | - Patricia Frías-Álvarez
- One Health Research Group, Melbourne Veterinary School, The University of Melbourne, Werribee, VIC 3030, Australia
| | - Trenton W J Garner
- Institute of Zoology, Zoological Society London, Regents Park, London NW1 4RY, UK.,Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2520, South Africa
| | - Brian Gratwicke
- Smithsonian National Zoological Park and Conservation Biology Institute, Washington, DC 20008, USA
| | - Juan M Guayasamin
- Universidad San Francisco de Quito USFQ, Colegio de Ciencias Biológicas y Ambientales COCIBA, Instituto de Investigaciones Biológicas y Ambientales BIOSFERA, Laboratorio de Biología Evolutiva, Campus Cumbayá, Quito, Ecuador.,Centro de Investigación de la Biodiversidad y Cambio Climático (BioCamb), Ingeniería en Biodiversidad y Cambio Climático, Facultad de Medio Ambiente, Universidad Tecnológica Indoamérica, Calle Machala y Sabanilla, Quito, Ecuador.,Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Mareike Hirschfeld
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstr. 43, Berlin 10115, Germany
| | - Jonathan E Kolby
- One Health Research Group, Melbourne Veterinary School, The University of Melbourne, Werribee, VIC 3030, Australia.,Honduras Amphibian Rescue and Conservation Center, Lancetilla Botanical Garden and Research Center, Tela, Honduras.,The Conservation Agency, Jamestown, RI 02835, USA
| | - Tiffany A Kosch
- One Health Research Group, Melbourne Veterinary School, The University of Melbourne, Werribee, VIC 3030, Australia.,AL Rae Centre for Genetics and Breeding, Massey University, Palmerston North 4442, New Zealand
| | - Enrique La Marca
- School of Geography, Faculty of Forestry Engineering and Environmental Sciences, University of Los Andes, Merida, Venezuela
| | - David B Lindenmayer
- Fenner School of Environment and Society, Australian National University, Canberra, ACT 2601, Australia.,National Environmental Science Programme, Threatened Species Recovery Hub, Canberra, ACT 2601, Australia
| | - Karen R Lips
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Ana V Longo
- Department of Biology, University of Florida, Gainesville, FL 32611, USA
| | - Raúl Maneyro
- Laboratorio de Sistemática e Historia Natural de Vertebrados. Facultad de Ciencias, Universidad de la República. Igua 4225, CP 11400, Montevideo, Uruguay
| | - Cait A McDonald
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Joseph Mendelson
- Zoo Atlanta, Atlanta, GA 30315, USA.,School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | | | - Gabriela Parra-Olea
- Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Mexico City, México
| | | | - Mark-Oliver Rödel
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Invalidenstr. 43, Berlin 10115, Germany
| | - Sean M Rovito
- Unidad de Genómica Avanzada (Langebio), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, km 9.6 Libramiento Norte Carretera Irapuato-León, Irapuato, Guanajuato CP36824, México
| | - Claudio Soto-Azat
- Centro de Investigación para la Sustentabilidad, Facultad de Ciencias de la Vida, Universidad Andres Bello, Santiago 8370251, Chile
| | - Luís Felipe Toledo
- Laboratório de História Natural de Anfíbios Brasileiros (LaHNAB), Departamento de Biologia Animal, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, Brazil
| | - Jamie Voyles
- Department of Biology, University of Nevada, Reno, NV 89557, USA
| | - Ché Weldon
- Unit for Environmental Sciences and Management, North-West University, Potchefstroom 2520, South Africa
| | - Steven M Whitfield
- Zoo Miami, Conservation and Research Department, Miami, FL 33177, USA.,Florida International University School of Earth, Environment, and Society, 11200 SW 8th St., Miami, FL 33199, USA
| | - Mark Wilkinson
- Department of Life Sciences, The Natural History Museum, London SW7 5BD, UK
| | - Kelly R Zamudio
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA
| | - Stefano Canessa
- Wildlife Health Ghent, Department of Pathology, Bacteriology, and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, B-9820 Merelbeke, Belgium
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33
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Bacigalupe LD, Vásquez IA, Estay SA, Valenzuela‐Sánchez A, Alvarado‐Rybak M, Peñafiel‐Ricaurte A, Cunningham AA, Soto‐Azat C. The amphibian‐killing fungus in a biodiversity hotspot: identifying and validating high‐risk areas and refugia. Ecosphere 2019. [DOI: 10.1002/ecs2.2724] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Leonardo D. Bacigalupe
- Facultad de Ciencias Instituto de Ciencias Ambientales y Evolutivas Universidad Austral de Chile Valdivia Chile
| | - Inao A. Vásquez
- Facultad de Ciencias Instituto de Ciencias Ambientales y Evolutivas Universidad Austral de Chile Valdivia Chile
| | - Sergio A. Estay
- Facultad de Ciencias Instituto de Ciencias Ambientales y Evolutivas Universidad Austral de Chile Valdivia Chile
- Center of Applied Ecology and Sustainability Pontificia Universidad Católica de Chile Santiago Chile
| | - Andrés Valenzuela‐Sánchez
- Facultad de Ciencias Instituto de Ciencias Ambientales y Evolutivas Universidad Austral de Chile Valdivia Chile
- ONG Ranita de Darwin Santiago Chile
| | - Mario Alvarado‐Rybak
- Centro de Investigación para la Sustentabilidad Facultad de Ciencias de la Vida & Doctorado en Medicina de la Conservación Universidad Andrés Bello Santiago Chile
- Institute of Zoology Zoological Society of London Regent's Park London NW1 4RY UK
| | - Alexandra Peñafiel‐Ricaurte
- Centro de Investigación para la Sustentabilidad Facultad de Ciencias de la Vida & Doctorado en Medicina de la Conservación Universidad Andrés Bello Santiago Chile
- Institute of Zoology Zoological Society of London Regent's Park London NW1 4RY UK
| | - Andrew A. Cunningham
- Institute of Zoology Zoological Society of London Regent's Park London NW1 4RY UK
| | - Claudio Soto‐Azat
- Centro de Investigación para la Sustentabilidad Facultad de Ciencias de la Vida & Doctorado en Medicina de la Conservación Universidad Andrés Bello Santiago Chile
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34
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Zumbado‐Ulate H, García‐Rodríguez A, Vredenburg VT, Searle C. Infection with Batrachochytrium dendrobatidis is common in tropical lowland habitats: Implications for amphibian conservation. Ecol Evol 2019; 9:4917-4930. [PMID: 31031954 PMCID: PMC6476760 DOI: 10.1002/ece3.5098] [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: 11/18/2018] [Revised: 02/25/2019] [Accepted: 02/28/2019] [Indexed: 11/24/2022] Open
Abstract
Numerous species of amphibians declined in Central America during the 1980s and 1990s. These declines mostly affected highland stream amphibians and have been primarily linked to chytridiomycosis, a deadly disease caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd). Since then, the majority of field studies on Bd in the Tropics have been conducted in midland and highland environments (>800 m) mainly because the environmental conditions of mountain ranges match the range of ideal abiotic conditions for Bd in the laboratory. This unbalanced sampling has led researchers to largely overlook host-pathogen dynamics in lowlands, where other amphibian species declined during the same period. We conducted a survey testing for Bd in 47 species (n = 348) in four lowland sites in Costa Rica to identify local host-pathogen dynamics and to describe the abiotic environment of these sites. We detected Bd in three sampling sites and 70% of the surveyed species. We found evidence that lowland study sites exhibit enzootic dynamics with low infection intensity and moderate to high prevalence (55% overall prevalence). Additionally, we found evidence that every study site represents an independent climatic zone, where local climatic differences may explain variations in Bd disease dynamics. We recommend more detection surveys across lowlands and other sites that have been historically considered unsuitable for Bd occurrence. These data can be used to identify sites for potential disease outbreaks and amphibian rediscoveries.
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Affiliation(s)
| | - Adrián García‐Rodríguez
- Departamento de Zoología, Instituto de BiologíaUniversidad Nacional Autónoma de México (UNAM)Ciudad de MéxicoMéxico
- Escuela de BiologíaUniversidad de Costa RicaSan JoséCosta Rica
- Departamento de EcologiaUniversidade Federal do Rio Grande do NorteNatalBrazil
| | | | - Catherine Searle
- Department of Biological SciencesPurdue UniversityWest LafayetteIndiana
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35
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Sloyer KE, Burkett-Cadena ND, Yang A, Corn JL, Vigil SL, McGregor BL, Wisely SM, Blackburn JK. Ecological niche modeling the potential geographic distribution of four Culicoides species of veterinary significance in Florida, USA. PLoS One 2019; 14:e0206648. [PMID: 30768605 PMCID: PMC6377124 DOI: 10.1371/journal.pone.0206648] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 02/06/2019] [Indexed: 11/19/2022] Open
Abstract
Epizootic hemorrhagic disease (EHD) is a viral arthropod-borne disease affecting wild and domestic ruminants, caused by infection with epizootic hemorrhagic disease virus (EHDV). EHDV is transmitted to vertebrate animal hosts by biting midges in the genus Culicoides Latreille (Diptera: Ceratopogonidae). Culicoides sonorensis Wirth and Jones is the only confirmed vector of EHDV in the United States but is considered rare in Florida and not sufficiently abundant to support EHDV transmission. This study used ecological niche modeling to map the potential geographical distributions and associated ecological variable space of four Culicoides species suspected of transmitting EHDV in Florida, including Culicoides insignis Lutz, Culicoides stellifer (Coquillett), Culicoides debilipalpis Hoffman and Culicoides venustus Lutz. Models were developed with the Genetic Algorithm for Rule Set Production in DesktopGARP v1.1.3 using species occurrence data from field sampling along with environmental variables from WorldClim and Trypanosomiasis and Land use in Africa. For three Culicoides species (C. insignis, C. stellifer and C. debilipalpis) 96-98% of the presence points were predicted across the Florida landscape (63.8% - 72.5%). For C. venustus, models predicted 98.00% of presence points across 27.4% of Florida. Geographic variations were detected between species. Culicoides insignis was predicted to be restricted to peninsular Florida, and in contrast, C. venustus was predicted to be primarily in north Florida and the panhandle region. Culicoides stellifer and C. debilipalpis were predicted nearly statewide. Environmental conditions also differed by species, with some species' ranges predicted by more narrow ranges of variables than others. The Normalized Difference Vegetation Index (NDVI) was a major predictor of C. venustus and C. insignis presence. For C. stellifer, Land Surface Temperature, Middle Infrared were the most limiting predictors of presence. The limiting variables for C. debilipalpis were NDVI Bi-Annual Amplitude and NDVI Annual Amplitude at 22.5% and 28.1%, respectively. The model outputs, including maps and environmental variable range predictions generated from these experiments provide an important first pass at predicting species of veterinary importance in Florida. Because EHDV cannot exist in the environment without the vector, model outputs can be used to estimate the potential risk of disease for animal hosts across Florida. Results also provide distribution and habitat information useful for integrated pest management practices.
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Affiliation(s)
- Kristin E. Sloyer
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach, Florida, United States of America
| | - Nathan D. Burkett-Cadena
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach, Florida, United States of America
| | - Anni Yang
- Spatial Epidemiology and Ecology Research Laboratory, Geography Department, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
| | - Joseph L. Corn
- Southeastern Cooperative Wildlife Disease Study, University of Georgia, Athens, Georgia, United States of America
| | - Stacey L. Vigil
- Southeastern Cooperative Wildlife Disease Study, University of Georgia, Athens, Georgia, United States of America
| | - Bethany L. McGregor
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach, Florida, United States of America
| | - Samantha M. Wisely
- Department of Wildlife, Ecology and Conservation, University of Florida, Gainesville, Florida, United States of America
| | - Jason K. Blackburn
- Spatial Epidemiology and Ecology Research Laboratory, Geography Department, University of Florida, Gainesville, Florida, United States of America
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, United States of America
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Brannelly LA, Martin G, Llewelyn J, Skerratt LF, Berger L. Age- and size-dependent resistance to chytridiomycosis in the invasive cane toad Rhinella marina. DISEASES OF AQUATIC ORGANISMS 2018; 131:107-120. [PMID: 30460917 DOI: 10.3354/dao03278] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In Australia, the cane toad Rhinella marina and chytrid fungus Batrachochytrium dendrobatidis (Bd) are examples of invasive species that have had dramatic impacts on native fauna. However, little is known about the interaction between Bd and cane toads. We aimed to explore the interaction of these 2 species in 3 parts. First, we collated data from the literature on Bd infection in wild cane toads. Second, we tested the susceptibility of recently metamorphosed cane toads to Bd infection. Finally, we modelled the distribution of the 2 species in Australia to identify where they overlap and, therefore, might interact. Through our data collation, we found that adult cane toads are infrequently infected and do not carry high infection burdens; however, our infection experiment showed that metamorphs are highly susceptible to infection and disease, but resistance appears to increase with increasing toad size. Niche modelling revealed overlapping distributions and the potential for cane toads to be affected by chytridiomycosis in the wild. While Bd can cause mortality in small juveniles in the laboratory, warm microhabitats used by wild toads likely prevent infection, and furthermore, high mortality of juveniles is unlikely to affect the adult populations because they are highly fecund. However, to demonstrate the impact of Bd on wild cane toad populations, targeted field studies are required to assess (1) the overall impact of chytridiomycosis on recruitment especially in cooler areas more favourable for Bd and (2) whether cane toad juveniles can amplify Bd exposure of native amphibian species in these areas.
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Affiliation(s)
- Laura A Brannelly
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA
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Kärvemo S, Meurling S, Berger D, Höglund J, Laurila A. Effects of host species and environmental factors on the prevalence of Batrachochytrium dendrobatidis in northern Europe. PLoS One 2018; 13:e0199852. [PMID: 30359384 PMCID: PMC6201871 DOI: 10.1371/journal.pone.0199852] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 10/09/2018] [Indexed: 11/18/2022] Open
Abstract
The fungal pathogen Batrachochytrium dendrobatidis (Bd) poses a major threat to amphibian populations. To assist efforts to address such threats, we examined differences in Bd host infection prevalence among amphibian species and its relations to both local environmental factors in breeding habitats and landscape variables measured at three scales (500, 2000 and 5000 m radii) around breeding sites in southernmost Sweden. We sampled 947 anurans of six species in 31 ponds and assessed their infection status. We then examined correlations of infection prevalence with canopy cover, pond perimeter and pH (treated as local-scale pond characteristics), and the number of ponds, area of arable land, area of mature forest, number of resident people and presence of sea within the three radii (treated as landscape variables). The Bd infection prevalence was very low, 0.5–1.0%, in two of the six anuran species (Bufo bufo and Rana temporaria), and substantially higher (13–64%) in the other four (Bombina bombina, Bufotes variabilis, Epidalea calamita, Rana arvalis). In the latter four species Bd infection prevalence was positively associated with ponds’ pH (site range: 5.3–8.1), and negatively associated with areas of mature forest and/or wetlands in the surroundings. Our results show that the infection dynamics of Bd are complex and associated with host species, local pond characteristics and several landscape variables at larger spatial scales. Knowledge of environmental factors associated with Bd infections and differences in species’ susceptibility may help to counter further spread of the disease and guide conservation action plans, especially for the most threatened species.
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Affiliation(s)
- Simon Kärvemo
- Department of Ecology and Genetics/Animal Ecology, Uppsala University, Uppsala, Sweden
- * E-mail:
| | - Sara Meurling
- Department of Ecology and Genetics/Animal Ecology, Uppsala University, Uppsala, Sweden
| | - David Berger
- Department of Ecology and Genetics/Animal Ecology, Uppsala University, Uppsala, Sweden
| | - Jacob Höglund
- Department of Ecology and Genetics/Animal Ecology, Uppsala University, Uppsala, Sweden
| | - Anssi Laurila
- Department of Ecology and Genetics/Animal Ecology, Uppsala University, Uppsala, Sweden
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Rumschlag SL, Boone MD. High juvenile mortality in amphibians during overwintering related to fungal pathogen exposure. DISEASES OF AQUATIC ORGANISMS 2018; 131:13-28. [PMID: 30324911 DOI: 10.3354/dao03277] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The result of pathogen exposures may depend upon trade-offs in energetic demands for immune responses against host growth and survival. Environmental conditions may influence these trade-offs by affecting host size, or trade-offs may change across seasons, altering impacts of pathogens. We exposed northern leopard frog Lithobates pipiens tadpoles to different larval environments (low leaf litter, high density of conspecifics, atrazine, caged fish, or controls) that influenced size at metamorphosis. Subsequently, we exposed metamorphs to Batrachochytrium dendrobatidis (Bd), a fungal pathogen, just after metamorphosis and/or prior to overwintering 12 wk later. Bd exposure dramatically reduced survival during overwintering, with the strongest effects when hosts were exposed at both time points. Larval environments resulted in differences in host size. Those exposed to caged fish were 2.5 times larger than the smallest (those exposed to high density of conspecifics), but larval environment did not influence Bd effects on growth and survival. The largest frogs exposed to caged fish had greater survival through overwintering, but in the absence of Bd. We built stage-structured models to evaluate if overwinter mortality from Bd is capable of having effects on host populations. Our models suggest that Bd exposure after metamorphosis or before overwintering can reduce population growth rates. Our study demonstrates that hosts suffer little effects of Bd exposures following metamorphosis and that small body size did not hamper growth and survival. Instead, we provide evidence that winter mortality from Bd exposure is capable of reducing population sizes, providing a plausible mechanism for amphibian declines in temperate regions.
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Miller CA, Tasse Taboue GC, Ekane MMP, Robak M, Sesink Clee PR, Richards-Zawacki C, Fokam EB, Fuashi NA, Anthony NM. Distribution modeling and lineage diversity of the chytrid fungus Batrachochytrium dendrobatidis (Bd) in a central African amphibian hotspot. PLoS One 2018; 13:e0199288. [PMID: 29924870 PMCID: PMC6010240 DOI: 10.1371/journal.pone.0199288] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/05/2018] [Indexed: 11/18/2022] Open
Abstract
The amphibian disease chytridiomycosis in amphibians is caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd) and has resulted in dramatic declines and extinctions of amphibian populations worldwide. A hypervirulent, globally-dispersed pandemic lineage (Bd-GPL) is thought to be largely responsible for population declines and extinctions, although numerous endemic lineages have also been found. Recent reports of amphibian declines have been linked to the emergence of Bd in Cameroon, a major hotspot of African amphibian diversity. However, it is not known whether Bd-GPL or other lineages have been found in this region. This study therefore aims to examine Bd lineage diversity in the region and predict the distribution of this pathogen under current and future climate conditions using data from this study and from historical records. Almost 15% (52/360) of individuals tested positive for Bd using a standard quantitative PCR diagnostic. Infected amphibians were found at all eight sites sampled in this study. Species distribution models generated in BIOMOD2 indicate that areas with highest predicted environmental suitability occur in the Cameroon highlands and several protected areas throughout the country. These areas of high environmental suitability for Bd are projected to shift or decrease in size under future climate change. However, montane regions with high amphibian diversity are predicted to remain highly suitable. Phylogenetic analysis of the ITS sequences obtained from a set of positive Bd samples indicate that most fall within the Bd-GPL lineage while the remainder group with isolates from either Brazil or South Korea. Although more in depth phylogenetic analyses are needed, identification of Bd-GPL lineages in areas of high amphibian diversity emphasizes the need to continue to monitor for Bd and develop appropriate conservation strategies to prevent its further spread.
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Affiliation(s)
- Courtney A. Miller
- Department of Biological Sciences, University of New Orleans, New Orleans, Louisiana, United States of America
| | - Geraud Canis Tasse Taboue
- Department of Zoology and Animal Physiology, University of Buea, Buea, Cameroon
- Institute of Geological and Mining Research, Yaoundé, Cameroon
| | - Mary M. P. Ekane
- Department of Zoology and Animal Physiology, University of Buea, Buea, Cameroon
| | - Matthew Robak
- Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, Louisiana, United States of America
| | - Paul R. Sesink Clee
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Corinne Richards-Zawacki
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Eric B. Fokam
- Department of Zoology and Animal Physiology, University of Buea, Buea, Cameroon
| | | | - Nicola M. Anthony
- Department of Biological Sciences, University of New Orleans, New Orleans, Louisiana, United States of America
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Lachish S, Murray KA. The Certainty of Uncertainty: Potential Sources of Bias and Imprecision in Disease Ecology Studies. Front Vet Sci 2018; 5:90. [PMID: 29872662 PMCID: PMC5972326 DOI: 10.3389/fvets.2018.00090] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 04/12/2018] [Indexed: 12/16/2022] Open
Abstract
Wildlife diseases have important implications for wildlife and human health, the preservation of biodiversity and the resilience of ecosystems. However, understanding disease dynamics and the impacts of pathogens in wild populations is challenging because these complex systems can rarely, if ever, be observed without error. Uncertainty in disease ecology studies is commonly defined in terms of either heterogeneity in detectability (due to variation in the probability of encountering, capturing, or detecting individuals in their natural habitat) or uncertainty in disease state assignment (due to misclassification errors or incomplete information). In reality, however, uncertainty in disease ecology studies extends beyond these components of observation error and can arise from multiple varied processes, each of which can lead to bias and a lack of precision in parameter estimates. Here, we present an inventory of the sources of potential uncertainty in studies that attempt to quantify disease-relevant parameters from wild populations (e.g., prevalence, incidence, transmission rates, force of infection, risk of infection, persistence times, and disease-induced impacts). We show that uncertainty can arise via processes pertaining to aspects of the disease system, the study design, the methods used to study the system, and the state of knowledge of the system, and that uncertainties generated via one process can propagate through to others because of interactions between the numerous biological, methodological and environmental factors at play. We show that many of these sources of uncertainty may not be immediately apparent to researchers (for example, unidentified crypticity among vectors, hosts or pathogens, a mismatch between the temporal scale of sampling and disease dynamics, demographic or social misclassification), and thus have received comparatively little consideration in the literature to date. Finally, we discuss the type of bias or imprecision introduced by these varied sources of uncertainty and briefly present appropriate sampling and analytical methods to account for, or minimise, their influence on estimates of disease-relevant parameters. This review should assist researchers and practitioners to navigate the pitfalls of uncertainty in wildlife disease ecology studies.
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Affiliation(s)
- Shelly Lachish
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Kris A. Murray
- Department of Infectious Disease Epidemiology and Grantham Institute – Climate Change and the Environment, Imperial College London, London, United Kingdom
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Yap TA, Koo MS, Ambrose RF, Vredenburg VT. Introduced bullfrog facilitates pathogen invasion in the western United States. PLoS One 2018; 13:e0188384. [PMID: 29659568 PMCID: PMC5901863 DOI: 10.1371/journal.pone.0188384] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 11/06/2017] [Indexed: 11/22/2022] Open
Abstract
Batrachochytrium dendrobatidis (Bd), a causal agent of the amphibian fungal skin disease chytridiomycosis, has been implicated in the decline and extinction of over 200 species worldwide since the 1970s. Despite almost two decades of research, the history of Bd and its global spread is not well understood. However, the spread of the Global Panzootic Lineage of Bd (Bd-GPL), the lineage associated with amphibian die-offs, has been linked with the American bullfrog (Rana [Aqurana] catesbeiana) and global trade. Interestingly, R. catesbeiana is native to the eastern U.S., where no Bd-related declines have been observed despite Bd’s presence since the late 1800s. In contrast Bd has been found to have emerged in California and Mexico in the 1960s and 1970s, after which epizootics (i.e., epidemics in wildlife) ensued. We hypothesize that Bd-GPL spread from the eastern U.S. with the introduction of R. catesbeiana into the western US, resulting in epizootics and declines of native host species. Using museum records, we investigated the historical relationship between R. catesbeiana and Bd invasion in the western US and found that R. catesbeiana arrived in the same year or prior to Bd in most western watersheds that had data for both species, suggesting that Bd-GPL may have originated in the eastern US and R. catesbeiana may have facilitated Bd invasion in the western US. To predict areas with greatest suitability for Bd, we created a suitability model by integrating habitat suitability and host availability. When we incorporated invasion history with high Bd suitability, we found that watersheds with non-native R. catesbeiana in the mountain ranges of the West Coast have the highest disease risk. These findings shed light on the invasion history and disease dynamics of Bd in North America. Targeted historical surveys using archived specimens in natural history collections and present-day field surveys along with more localized, community-level studies, monitoring, and surveillance are needed to further test this hypothesis and grow our understanding of the disease ecology and host-pathogen dynamics of Bd.
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Affiliation(s)
- Tiffany A. Yap
- Institute of the Environment and Sustainability, University of California, Los Angeles, California, United States of America
- Museum of Vertebrate Zoology, University of California, Berkeley, California, United States of America
- Department of Biology, San Francisco State University, San Francisco, California, United States of America
| | - Michelle S. Koo
- Museum of Vertebrate Zoology, University of California, Berkeley, California, United States of America
| | - Richard F. Ambrose
- Institute of the Environment and Sustainability, University of California, Los Angeles, California, United States of America
- Department of Environmental Health Sciences, University of California, Los Angeles, California, United States of America
| | - Vance T. Vredenburg
- Museum of Vertebrate Zoology, University of California, Berkeley, California, United States of America
- Department of Biology, San Francisco State University, San Francisco, California, United States of America
- * E-mail:
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Evangelista PH, Mohamed AM, Hussein IA, Saied AH, Mohammed AH, Young NE. Integrating indigenous local knowledge and species distribution modeling to detect wildlife in Somaliland. Ecosphere 2018. [DOI: 10.1002/ecs2.2134] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Paul H. Evangelista
- Natural Resource Ecology Laboratory; Colorado State University; B254 NESB Fort Collins Colorado 80526 USA
| | - Ahmed M. Mohamed
- Wildlife Department; Ministry of Environment and Natural Resources; Sha'ab Area, Road No. 1 Hargeisa Somaliland
| | - Ibraham A. Hussein
- Wildlife Department; Ministry of Environment and Natural Resources; Sha'ab Area, Road No. 1 Hargeisa Somaliland
| | - Abdinasir H. Saied
- Wildlife Department; Ministry of Environment and Natural Resources; Sha'ab Area, Road No. 1 Hargeisa Somaliland
| | - Abdikadir H. Mohammed
- Wildlife Department; Ministry of Environment and Natural Resources; Sha'ab Area, Road No. 1 Hargeisa Somaliland
| | - Nicholas E. Young
- Natural Resource Ecology Laboratory; Colorado State University; B254 NESB Fort Collins Colorado 80526 USA
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Grogan LF, Cashins SD, Skerratt LF, Berger L, McFadden MS, Harlow P, Hunter DA, Scheele BC, Mulvenna J. Evolution of resistance to chytridiomycosis is associated with a robust early immune response. Mol Ecol 2018; 27:919-934. [DOI: 10.1111/mec.14493] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 06/30/2017] [Accepted: 09/18/2017] [Indexed: 12/30/2022]
Affiliation(s)
- Laura F. Grogan
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville QLD Australia
- Griffith Wildlife Disease Ecology Group Environmental Futures Research Institute School of Environment Griffith University Nathan QLD Australia
- Genetics and Computational Biology QIMR Berghofer Medical Research Institute Brisbane QLD Australia
| | - Scott D. Cashins
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville QLD Australia
| | - Lee F. Skerratt
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville QLD Australia
| | - Lee Berger
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville QLD Australia
| | | | - Peter Harlow
- Taronga Conservation Society Australia Mosman NSW Australia
| | - David A. Hunter
- Ecosystems and Threatened Species South West Region Office of Environment and Heritage NSW Department of Premier and Cabinet Queanbeyan NSW Australia
| | - Ben C. Scheele
- One Health Research Group College of Public Health, Medical and Veterinary Sciences James Cook University Townsville QLD Australia
- Fenner School of Environment and Society Australian National University Canberra ACT Australia
| | - Jason Mulvenna
- Genetics and Computational Biology QIMR Berghofer Medical Research Institute Brisbane QLD Australia
- School of Biomedical Sciences The University of Queensland Brisbane QLD Australia
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Hoskin CJ, Hines HB, Webb RJ, Skerratt LF, Berger L. Naïve rainforest frogs on Cape York, Australia, are at risk of the introduction of amphibian chytridiomycosis disease. AUST J ZOOL 2018. [DOI: 10.1071/zo18041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Amphibian chytridiomycosis disease has caused widespread declines and extinctions of frogs in cool, wet habitats in eastern Australia. Screening suggests that the disease does not yet occupy all areas modelled to be environmentally suitable, including rainforests on Cape York Peninsula. Cape Melville is an area of rainforest with several endemic frogs, including the stream-associated Melville Range treefrog (Litoria andiirrmalin), which is deemed at particular risk of disease impacts. We tested 40 L. andiirrmalin for chytrid infection by PCR and found them all to be negative. In conjunction with previous testing at another high-risk location, McIlwraith Range, this suggests that endemic rainforest frogs on Cape York have been spared the introduction of chytridiomycosis. We discuss how the disease could get to these areas, what can be done to reduce the risk, and suggest an emergency procedure should it be introduced.
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Yap TA, Nguyen NT, Serr M, Shepack A, Vredenburg VT. Batrachochytrium salamandrivorans and the Risk of a Second Amphibian Pandemic. ECOHEALTH 2017; 14:851-864. [PMID: 29147975 DOI: 10.1007/s10393-017-1278-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 08/07/2017] [Accepted: 08/07/2017] [Indexed: 06/07/2023]
Abstract
Amphibians are experiencing devastating population declines globally. A major driver is chytridiomycosis, an emerging infectious disease caused by the fungal pathogens Batrachochytrium dendrobatidis (Bd) and Batrachochytrium salamandrivorans (Bsal). Bd was described in 1999 and has been linked with declines since the 1970s, while Bsal is a more recently discovered pathogen that was described in 2013. It is hypothesized that Bsal originated in Asia and spread via international trade to Europe, where it has been linked to salamander die-offs. Trade in live amphibians thus represents a significant threat to global biodiversity in amphibians. We review the current state of knowledge regarding Bsal and describe the risk of Bsal spread. We discuss regional responses to Bsal and barriers that impede a rapid, coordinated global effort. The discovery of a second deadly emerging chytrid fungal pathogen in amphibians poses an opportunity for scientists, conservationists, and governments to improve global biosecurity and further protect humans and wildlife from a growing number of emerging infectious diseases.
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Affiliation(s)
- Tiffany A Yap
- Department of Biology, San Francisco State University, Hensill Hall, 1600 Holloway Avenue, San Francisco, CA, 94132, USA.
- Museum of Vertebrate Zoology, University of California Berkeley, 3101 Valley Life Sciences Building, Berkeley, CA, 94720, USA.
| | - Natalie T Nguyen
- U.S. Geological Survey National Wildlife Health Center, 6006 Schroeder Rd., Madison, WI, 53711, USA
| | - Megan Serr
- Department of Biological Sciences, North Carolina State University, Thomas Hall, 1100 Brooks Avenue, Raleigh, NC, 27695, USA
| | - Alexander Shepack
- Zoology Department, Southern Illinois University Carbondale, 1125 Lincoln Drive, Carbondale, IL, 62901, USA
| | - Vance T Vredenburg
- Department of Biology, San Francisco State University, Hensill Hall, 1600 Holloway Avenue, San Francisco, CA, 94132, USA
- Museum of Vertebrate Zoology, University of California Berkeley, 3101 Valley Life Sciences Building, Berkeley, CA, 94720, USA
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Greenspan SE, Bower DS, Webb RJ, Berger L, Rudd D, Schwarzkopf L, Alford RA. White blood cell profiles in amphibians help to explain disease susceptibility following temperature shifts. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 77:280-286. [PMID: 28870450 DOI: 10.1016/j.dci.2017.08.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 08/30/2017] [Accepted: 08/30/2017] [Indexed: 06/07/2023]
Abstract
Temperature variability, and in particular temperature decreases, can increase susceptibility of amphibians to infections by the fungus Batrachochytrium dendrobatidis (Bd). However, the effects of temperature shifts on the immune systems of Bd-infected amphibians are unresolved. We acclimated frogs to 16 °C and 26 °C (baseline), simultaneously transferred them to an intermediate temperature (21 °C) and inoculated them with Bd (treatment), and tracked their infection levels and white blood cell profiles over six weeks. Average weekly infection loads were consistently higher in 26°C-history frogs, a group that experienced a 5 °C temperature decrease, than in 16°C-history frogs, a group that experienced a 5 °C temperature increase, but this pattern only approached statistical significance. The 16°C-acclimated frogs had high neutrophil:lymphocyte (N:L) ratios (suggestive of a hematopoietic stress response) at baseline, which were conserved post-treatment. In contrast, the 26°C-acclimated frogs had low N:L ratios at baseline which reversed to high N:L ratios post-treatment (suggestive of immune system activation). Our results suggest that infections were less physiologically taxing for the 16°C-history frogs than the 26°C-history frogs because they had already adjusted immune parameters in response to challenging conditions (cold). Our findings provide a possible mechanistic explanation for observations that amphibians are more susceptible to Bd infection following temperature decreases compared to increases and underscore the consensus that increased temperature variability associated with climate change may increase the impact of infectious diseases.
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Affiliation(s)
- Sasha E Greenspan
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia.
| | - Deborah S Bower
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - Rebecca J Webb
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Lee Berger
- One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Donna Rudd
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland 4811, Australia
| | - Lin Schwarzkopf
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - Ross A Alford
- College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
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Greenberg DA, Palen WJ, Mooers AØ. Amphibian species traits, evolutionary history and environment predict Batrachochytrium dendrobatidis infection patterns, but not extinction risk. Evol Appl 2017; 10:1130-1145. [PMID: 29151866 PMCID: PMC5680631 DOI: 10.1111/eva.12520] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 07/18/2017] [Indexed: 12/17/2022] Open
Abstract
The fungal pathogen Batrachochytrium dendrobatidis (B. dendrobatidis) has emerged as a major agent of amphibian extinction, requiring conservation intervention for many susceptible species. Identifying susceptible species is challenging, but many aspects of species biology are predicted to influence the evolution of host resistance, tolerance, or avoidance strategies towards disease. In turn, we may expect species exhibiting these distinct strategies to differ in their ability to survive epizootic disease outbreaks. Here, we test for phylogenetic and trait-based patterns of B. dendrobatidis infection risk and infection intensity among 302 amphibian species by compiling a global data set of B. dendrobatidis infection surveys across 95 sites. We then use best-fit models that associate traits, taxonomy and environment with B. dendrobatidis infection risk and intensity to predict host disease mitigation strategies (tolerance, resistance, avoidance) for 122 Neotropical amphibian species that experienced epizootic B. dendrobatidis outbreaks, and noted species persistence or extinction from these events. Aspects of amphibian species life history, habitat use and climatic niche were consistently linked to variation in B. dendrobatidis infection patterns across sites around the world. However, predicted B. dendrobatidis infection risk and intensity based on site environment and species traits did not reveal a consistent pattern between the predicted host disease mitigation strategy and extinction outcome. This suggests that either tolerant or resistant species may have no advantage in ameliorating disease during epizootic events, or that other factors drive the persistence of amphibian populations during chytridiomycosis outbreaks. These results suggest that using a trait-based approach may allow us to identify species with resistance or tolerance to endemic B. dendrobatidis infections, but that this approach may be insufficient to ultimately identify species at risk of extinction from epizootics.
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Affiliation(s)
- Dan A. Greenberg
- Department of Biological Sciences and Crawford Laboratory of Evolutionary StudiesSimon Fraser UniversityBurnabyBCCanada
- Department of Biological Sciences and Earth to Ocean Research GroupSimon Fraser UniversityBurnabyBCCanada
| | - Wendy J. Palen
- Department of Biological Sciences and Earth to Ocean Research GroupSimon Fraser UniversityBurnabyBCCanada
| | - Arne Ø. Mooers
- Department of Biological Sciences and Crawford Laboratory of Evolutionary StudiesSimon Fraser UniversityBurnabyBCCanada
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48
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Sonn JM, Berman S, Richards-Zawacki CL. The Influence of Temperature on Chytridiomycosis In Vivo. ECOHEALTH 2017; 14:762-770. [PMID: 28879516 DOI: 10.1007/s10393-017-1269-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 06/23/2017] [Accepted: 07/11/2017] [Indexed: 06/07/2023]
Abstract
Chytridiomycosis, an amphibian disease caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is an ideal system for studying the influence of temperature on host-pathogen relationships because both host and pathogen are ectothermic. Studies of Bd in culture suggest that optimal growth occurs between 17 and 23°C, and death of the fungus occurs above 29 or below 0°C. Amphibian immune systems, however, are also temperature dependent and often more effective at higher temperatures. We therefore hypothesized that pathogen load, probability of infection and mortality in Bd-exposed frogs would peak at a lower temperature than that at which Bd grows best in vitro. To test this, we conducted a study where Bd- and sham-exposed Northern cricket frogs (Acris crepitans) were incubated at six temperatures between 11 and 26°C. While probability of infection did not differ across temperatures, pathogen load and mortality were inversely related to temperature. Survival of infected hosts was greatest between 20 and 26°C, temperatures where Bd grows well in culture. These results demonstrate that the conditions under which a pathogen grows best in culture do not necessarily reflect patterns of pathogenicity, an important consideration for predicting the threat of this and other wildlife pathogens.
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Affiliation(s)
- Julia M Sonn
- Department of Ecology and Evolutionary Biology, Tulane University, 400 Lindy Boggs Bldg., New Orleans, LA, 70118, USA.
| | - Scott Berman
- Department of Ecology and Evolutionary Biology, Tulane University, 400 Lindy Boggs Bldg., New Orleans, LA, 70118, USA
| | - Corinne L Richards-Zawacki
- Department of Ecology and Evolutionary Biology, Tulane University, 400 Lindy Boggs Bldg., New Orleans, LA, 70118, USA
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
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Bacigalupe LD, Soto-Azat C, García-Vera C, Barría-Oyarzo I, Rezende EL. Effects of amphibian phylogeny, climate and human impact on the occurrence of the amphibian-killing chytrid fungus. GLOBAL CHANGE BIOLOGY 2017; 23:3543-3553. [PMID: 28055125 DOI: 10.1111/gcb.13610] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 12/20/2016] [Indexed: 06/06/2023]
Abstract
Chytridiomycosis, due to the fungus Batrachochytrium dendrobatidis (Bd), has been associated with the alarming decline and extinction crisis of amphibians worldwide. Because conservation programs are implemented locally, it is essential to understand how the complex interactions among host species, climate and human activities contribute to Bd occurrence at regional scales. Using weighted phylogenetic regressions and model selection, we investigated geographic patterns of Bd occurrence along a latitudinal gradient of 1500 km within a biodiversity hot spot in Chile (1845 individuals sampled from 253 sites and representing 24 species), and its association with climatic, socio-demographic and economic variables. Analyses show that Bd prevalence decreases with latitude although it has increased by almost 10% between 2008 and 2013, possibly reflecting an ongoing spread of Bd following the introduction of Xenopus laevis. Occurrence of Bd was higher in regions with high gross domestic product (particularly near developed centers) and with a high variability in rainfall regimes, whereas models including other bioclimatic or geographic variables, including temperature, exhibited substantially lower fit and virtually no support based on Akaike weights. In addition, Bd prevalence exhibited a strong phylogenetic signal, with five species having high numbers of infected individuals and higher prevalence than the average of 13.3% across all species. Taken together, our results highlight that Bd in Chile might still be spreading south, facilitated by a subset of species that seem to play an important epidemiological role maintaining this pathogen in the communities, in combination with climatic and human factors affecting the availability and quality of amphibian breeding sites. This information may be employed to design conservation strategies and mitigate the impacts of Bd in the biodiversity hot spot of southern Chile, and similar studies may prove useful to disentangle the role of different factors contributing to the emergence and spread of this catastrophic disease.
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Affiliation(s)
- Leonardo D Bacigalupe
- Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Avda. Rector Eduardo Morales s/n, Edificio Pugín, Valdivia, Chile
| | - Claudio Soto-Azat
- Centro de Investigación para la Sustentabilidad, Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, República 440, Santiago, Chile
| | - Cristobal García-Vera
- Dirección General de Aguas, Ministerio de Obras Públicas, Riquelme 465, Coyhaique, Chile
| | - Ismael Barría-Oyarzo
- Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Avda. Rector Eduardo Morales s/n, Edificio Pugín, Valdivia, Chile
| | - Enrico L Rezende
- Facultad de Ecología y Recursos Naturales, Universidad Andres Bello, República 440, Santiago, Chile
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50
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Blooi M, Laking AE, Martel A, Haesebrouck F, Jocque M, Brown T, Green S, Vences M, Bletz MC, Pasmans F. Host niche may determine disease-driven extinction risk. PLoS One 2017; 12:e0181051. [PMID: 28704480 PMCID: PMC5509289 DOI: 10.1371/journal.pone.0181051] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 06/26/2017] [Indexed: 12/31/2022] Open
Abstract
The fungal pathogen Batrachochytrium dendrobatidis (Bd) drives declines and extinctions in amphibian communities. However, not all regions and species are equally affected. Here, we show that association with amphibian aquatic habitat types (bromeliad phytotelmata versus stream) across Central America results in the odds of being threatened by Bd being five times higher in stream microhabitats. This differential threat of Bd was supported in our study by a significantly lower prevalence of Bd in bromeliad-associated amphibian species compared to riparian species in Honduran cloud forests. Evidence that the bromeliad environment is less favorable for Bd transmission is exemplified by significantly less suitable physicochemical conditions and higher abundance of Bd-ingesting micro-eukaryotes present in bromeliad water. These factors may inhibit aquatic Bd zoospore survival and the development of an environmental reservoir of the pathogen. Bromeliad phytotelmata thus may act as environmental refuges from Bd, which contribute to protecting associated amphibian communities against chytridiomycosis-driven amphibian declines that threaten the nearby riparian communities.
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Affiliation(s)
- Mark Blooi
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Alexandra E. Laking
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
- Operation Wallacea, Hope House, Old Bolingbroke, Lincolnshire, United Kingdom
| | - An Martel
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Freddy Haesebrouck
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Merlijn Jocque
- Operation Wallacea, Hope House, Old Bolingbroke, Lincolnshire, United Kingdom
- Hopkins Marine Station, Stanford University, Pacific Grove, California, United States of America
| | - Tom Brown
- Operation Wallacea, Hope House, Old Bolingbroke, Lincolnshire, United Kingdom
| | - Stephen Green
- Operation Wallacea, Hope House, Old Bolingbroke, Lincolnshire, United Kingdom
- Centre for Applied Zoology, Cornwall College Newquay, Cornwall, United Kingdom
| | - Miguel Vences
- Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Molly C. Bletz
- Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Frank Pasmans
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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