1001
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Randall CJ, Szmant AM. Elevated temperature affects development, survivorship, and settlement of the elkhorn coral, Acropora palmata (Lamarck 1816). THE BIOLOGICAL BULLETIN 2009; 217:269-282. [PMID: 20040751 DOI: 10.1086/bblv217n3p269] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Elevated seawater temperatures during the late summer have the potential to negatively affect the development and survivorship of the larvae of reef corals that are reproductive during that time of year. Acropora palmata, a major Caribbean hermatype, reproduces annually during August and September. A. palmata populations have severely declined over the past three decades, and recovery will require high recruitment rates. Such recruitment will be limited if larval supply is reduced by elevated temperatures. The effects of elevated temperatures on development, survival, and larval settlement of A. palmata were investigated by culturing newly fertilized eggs at temperatures ranging from 27.5 to 31.5 degrees C. Development was accelerated and the percentage of developmental abnormalities increased at higher temperatures. Embryo mortality peaked during gastrulation, indicating that this complex developmental process is particularly sensitive to elevated temperatures. Larvae cultured at 30 and 31.5 degrees C experienced as much as an 8-fold decrease in survivorship compared to those at 28 degrees C. Additionally, settlement was 62% at 28 degrees C compared to 37% at 31.5 degrees C. These results indicate that embryos and larvae of A. palmata will be negatively affected as sea surface temperatures continue to warm, likely reducing recruitment and the recovery potential of A. palmata on Caribbean reefs.
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Affiliation(s)
- Carly J Randall
- Center for Marine Science, University of North Carolina Wilmington, 5600 Marvin K. Moss Lane, Wilmington, North Carolina 28409, USA
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1002
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Population responses within a landscape matrix: a macrophysiological approach to understanding climate change impacts. Evol Ecol 2009. [DOI: 10.1007/s10682-009-9329-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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1003
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Microbial disease and the coral holobiont. Trends Microbiol 2009; 17:554-62. [PMID: 19822428 DOI: 10.1016/j.tim.2009.09.004] [Citation(s) in RCA: 243] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2009] [Revised: 09/04/2009] [Accepted: 09/21/2009] [Indexed: 01/04/2023]
Abstract
Tropical coral reefs harbour a reservoir of enormous biodiversity that is increasingly threatened by direct human activities and indirect global climate shifts. Emerging coral diseases are one serious threat implicated in extensive reef deterioration through disruption of the integrity of the coral holobiont - a complex symbiosis between the coral animal, endobiotic alga and an array of microorganisms. In this article, we review our current understanding of the role of microorganisms in coral health and disease, and highlight the pressing interdisciplinary research priorities required to elucidate the mechanisms of disease. We advocate an approach that applies knowledge gained from experiences in human and veterinary medicine, integrated into multidisciplinary studies that investigate the interactions between host, agent and environment of a given coral disease. These approaches include robust and precise disease diagnosis, standardised ecological methods and application of rapidly developing DNA, RNA and protein technologies, alongside established histological, microbial ecology and ecological expertise. Such approaches will allow a better understanding of the causes of coral mortality and coral reef declines and help assess potential management options to mitigate their effects in the longer term.
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1004
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Raymundo LJ, Halford AR, Maypa AP, Kerr AM. Functionally diverse reef-fish communities ameliorate coral disease. Proc Natl Acad Sci U S A 2009; 106:17067-70. [PMID: 19805081 PMCID: PMC2761369 DOI: 10.1073/pnas.0900365106] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Indexed: 11/18/2022] Open
Abstract
Coral reefs, the most diverse of marine ecosystems, currently experience unprecedented levels of degradation. Diseases are now recognized as a major cause of mortality in reef-forming corals and are complicit in phase shifts of reef ecosystems to algal-dominated states worldwide. Even so, factors contributing to disease occurrence, spread, and impact remain poorly understood. Ecosystem resilience has been linked to the conservation of functional diversity, whereas overfishing reduces functional diversity through cascading, top-down effects. Hence, we tested the hypothesis that reefs with trophically diverse reef fish communities have less coral disease than overfished reefs. We surveyed reefs across the central Philippines, including well-managed marine protected areas (MPAs), and found that disease prevalence was significantly negatively correlated with fish taxonomic diversity. Further, MPAs had significantly higher fish diversity and less disease than unprotected areas. We subsequently investigated potential links between coral disease and the trophic components of fish diversity, finding that only the density of coral-feeding chaetodontid butterflyfishes, seldom targeted by fishers, was positively associated with disease prevalence. These previously uncharacterized results are supported by a second large-scale dataset from the Great Barrier Reef. We hypothesize that members of the charismatic reef-fish family Chaetodontidae are major vectors of coral disease by virtue of their trophic specialization on hard corals and their ecological release in overfished areas, particularly outside MPAs.
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1005
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Kocan R, Hershberger P, Sanders G, Winton J. Effects of temperature on disease progression and swimming stamina in Ichthyophonus-infected rainbow trout, Oncorhynchus mykiss (Walbaum). JOURNAL OF FISH DISEASES 2009; 32:835-43. [PMID: 19570061 DOI: 10.1111/j.1365-2761.2009.01059.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Rainbow trout, Oncorhynchus mykiss, were infected with Ichthyophonus sp. and held at 10 degrees C, 15 degrees C and 20 degrees C for 28 days to monitor mortality and disease progression. Infected fish demonstrated more rapid onset of disease, higher parasite load, more severe host tissue reaction and reduced mean-day-to-death at higher temperature. In a second experiment, Ichthyophonus-infected fish were reared at 15 degrees C for 16 weeks then subjected to forced swimming at 10 degrees C, 15 degrees C and 20 degrees C. Stamina improved significantly with increased temperature in uninfected fish; however, this was not observed for infected fish. The difference in performance between infected and uninfected fish became significant at 15 degrees C (P = 0.02) and highly significant at 20 degrees C (P = 0.005). These results have implications for changes in the ecology of fish diseases in the face of global warming and demonstrate the effects of higher temperature on the progression and severity of ichthyophoniasis as well as on swimming stamina, a critical fitness trait of salmonids. This study helps explain field observations showing the recent emergence of clinical ichthyophoniasis in Yukon River Chinook salmon later in their spawning migration when water temperatures were high, as well as the apparent failure of a substantial percentage of infected fish to successfully reach their natal spawning areas.
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Affiliation(s)
- R Kocan
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195, USA.
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1006
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CHASAR ANTHONY, LOISEAU CLAIRE, VALKIŪNAS GEDIMINAS, IEZHOVA TATJANA, SMITH THOMASB, SEHGAL RAVINDERNM. Prevalence and diversity patterns of avian blood parasites in degraded African rainforest habitats. Mol Ecol 2009; 18:4121-33. [DOI: 10.1111/j.1365-294x.2009.04346.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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1007
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Fukui Y, Saitoh SI, Sawabe T. Environmental determinants correlated to Vibrio harveyi-mediated death of marine gastropods. Environ Microbiol 2009; 12:124-33. [PMID: 19758346 DOI: 10.1111/j.1462-2920.2009.02052.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Vibrio harveyi is an emerging pathogen that causes mass mortality in a wide variety of marine animal species; however, it is still unclear which environmental determinants correlate V. harveyi dynamics and the bacterium-mediated death of marine animal life. We conducted a correlation analysis over a 5-year period (2003-2007) analysing the following data: V. harveyi abundance, marine animal mortality and environmental variables (seawater temperature, salinity, pH, chlorophyll a, rainfall and total viable bacterial counts). The samples were collected from a coastal area in northern Japan, where deaths of a marine gastropod species (Haliotis discus hannai) have been reported. Our analysis revealed significant positive correlations between average seawater temperature and average V. harveyi abundance (R = 0.955; P < 0.05), and between average seawater temperature and V. harveyi-mediated abalone death (R = 0.931; P < 0.05). Based on the regression model, n degrees C rise in seawater temperature gave rise to a 21(n)-fold increase in the risk of mortality caused by V. harveyi infection. This is the first report providing evidence of the strong positive correlation between seawater temperature and V. harveyi-mediated death of marine species.
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Affiliation(s)
- Youhei Fukui
- Laboratories of Microbiology and Marine Bioresource and Environment Sensing, Faculty of Fisheries Sciences, Hokkaido University, 3-1-1 Minato-cho, Hakodate 041-8611, Hokkaido, Japan
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1008
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Abstract
Seasonal variation in norovirus infection is a recognized but poorly understood phenomenon. It is likely to be based on biological, environmental and behavioural factors that regulate transmission, virulence and persistence of the virions in host populations. Understanding the seasonal dependency of norovirus infection is an important step towards understanding its epidemiology, with subsequent implementation of efficient measures of surveillance and control. Whether or not climate change could influence the seasonal patterns of norovirus infection, by impacting on its transmission, geographic distribution and prevalence, has not yet been considered. This review addresses the question.
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Affiliation(s)
- J Rohayem
- The Calicilab, Institute of Virology, Dresden University of Technology, Dresden, Germany.
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1009
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Igbinosa EO, Obi LC, Okoh AI. Occurrence of potentially pathogenic vibrios in final effluents of a wastewater treatment facility in a rural community of the Eastern Cape Province of South Africa. Res Microbiol 2009; 160:531-7. [PMID: 19732825 DOI: 10.1016/j.resmic.2009.08.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 08/10/2009] [Accepted: 08/10/2009] [Indexed: 12/18/2022]
Abstract
We assessed the occurrence of Vibrio pathogens in the final effluents of a rural wastewater treatment facility in the Eastern Cape Province of South Africa as free or plankton-associated (180 microm, 60 microm and 20 microm plankton sizes) entities using standard culture-based and molecular techniques. The free-living Vibrio densities varied from 0 to 3.45 x 10(1) cfu ml(-1), while the plankton-associated Vibrio densities vary with plankton sizes as follows: 180 microm (0-4.50 x 10(3) cfu ml(-1)); 60 microm (0-4.86 x 10(3) cfu ml(-1)); 20 microm (0-1.9 x 10(5) cfu ml(-1)). The seasonal variations in the Vibrio densities in the 180 and 60 microm plankton size samples were significant (p < 0.05), while the 20 microm plankton size and free-living Vibrio densities were not. Molecular confirmation of the presumptive vibrios isolates revealed fluvialis (36.5%), as the predominant species, followed by Vibrio vulnificus (34.6%), and Vibrio parahaemolyticus (23.1%); only API 20NE was employed to detect Vibrio metschnikovii (5.8%), suggesting a high incidence of pathogenic Vibrio species in the final effluent of the rural wastewater facility. Analysis suggested that the concentration of Vibrio species correlated negatively with salinity and temperature (p < 0.001 and p < 0.002 respectively) as well as with pH and turbidity (p < 0.001) in the final effluent. We conclude that rural wastewater treatment facilities in the Eastern Cape Province of South Africa are potential sources of Vibrio pathogens in the aquatic environment of the communities.
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Affiliation(s)
- Etinosa O Igbinosa
- Applied and Environmental Microbiology Research Group (AEMREG), Department of Biochemistry and Microbiology, University of Fort Hare, Alice 5700, South Africa
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1010
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Mas-Coma S, Valero MA, Bargues MD. Climate change effects on trematodiases, with emphasis on zoonotic fascioliasis and schistosomiasis. Vet Parasitol 2009; 163:264-280. [PMID: 19375233 DOI: 10.1016/j.vetpar.2009.03.024] [Citation(s) in RCA: 233] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The capacity of climatic conditions to modulate the extent and intensity of parasitism is well known since long ago. Concerning helminths, among the numerous environmental modifications giving rise to changes in infections, climate variables appear as those showing a greater influence, so that climate change may be expected to have an important impact on the diseases they cause. However, the confirmation of the impact of climate change on helminthiases has been reached very recently. Only shortly before, helminthiases were still noted as infectious diseases scarcely affected by climate change, when compared to diseases caused by microorganisms in general (viruses, bacteriae, protozoans). The aim of the present paper is to review the impact of climate change on helminthiases transmitted by snails, invertebrates which are pronouncedly affected by meteorological factors, by focusing on trematodiases. First, the knowledge on the effects of climate change on trematodiases in general is reviewed, including aspects such as influence of temperature on cercarial output, cercarial production variability in trematode species, influences of magnitude of cercarial production and snail host size, cercarial quality, duration of cercarial production increase and host mortality, influence of latitude, and global-warming-induced impact of trematodes. Secondly, important zoonotic diseases such as fascioliasis, schistosomiasis and cercarial dermatitis are analysed from the point of view of their relationships with meteorological factors. Emphasis is given to data which indicate that climate change influences the characteristics of these trematodiases in concrete areas where these diseases are emerging in recent years. The present review shows that trematodes, similarly as other helminths presenting larval stages living freely in the environment and/or larval stages parasitic in invertebrates easily affected by climate change as arthropods and molluscs as intermediate hosts, may be largely more susceptible to climate change impact than those helminths in whose life cycle such phases are absent or reduced to a minimum. Although helminths also appear to be affected by climate change, their main difference with microparasites lies on the usually longer life cycles of helminths, with longer generation times, slower population growth rates and longer time period needed for the response in the definitive host to become evident. Consequently, after a pronounced climate change in a local area, modifications in helminth populations need more time to be obvious or detectable than modifications in microparasite populations. Similarly, the relation of changes in a helminthiasis with climatic factor changes, as extreme events elapsed relatively long time ago, may be overlooked if not concretely searched for. All indicates that this phenomenon has been the reason for previous analyses to conclude that helminthiases do not constitute priority targets in climate change impact studies.
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Affiliation(s)
- Santiago Mas-Coma
- Departamento de Parasitologia, Facultad de Farmacia, Universidad de Valencia, 46100 Burjassot, Valencia, Spain.
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1011
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Kutz SJ, Jenkins EJ, Veitch AM, Ducrocq J, Polley L, Elkin B, Lair S. The Arctic as a model for anticipating, preventing, and mitigating climate change impacts on host–parasite interactions. Vet Parasitol 2009; 163:217-28. [DOI: 10.1016/j.vetpar.2009.06.008] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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1012
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French S, Levy-Booth D, Samarajeewa A, Shannon KE, Smith J, Trevors JT. Elevated temperatures and carbon dioxide concentrations: effects on selected microbial activities in temperate agricultural soils. World J Microbiol Biotechnol 2009. [DOI: 10.1007/s11274-009-0107-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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1013
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Abstract
The projected global increase in the distribution and prevalence of infectious diseases with climate change suggests a pending societal crisis. The subject is increasingly attracting the attention of health professionals and climate-change scientists, particularly with respect to malaria and other vector-transmitted human diseases. The result has been the emergence of a crisis discipline, reminiscent of the early phases of conservation biology. Latitudinal, altitudinal, seasonal, and interannual associations between climate and disease along with historical and experimental evidence suggest that climate, along with many other factors, can affect infectious diseases in a nonlinear fashion. However, although the globe is significantly warmer than it was a century ago, there is little evidence that climate change has already favored infectious diseases. While initial projections suggested dramatic future increases in the geographic range of infectious diseases, recent models predict range shifts in disease distributions, with little net increase in area. Many factors can affect infectious disease, and some may overshadow the effects of climate.
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Affiliation(s)
- Kevin D Lafferty
- Western Ecological Research Center, U.S. Geological Survey, Marine Science Institute, University of California, Santa Barbara, California 93106, USA.
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1014
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Affiliation(s)
- Richard S Ostfeld
- Cary Institute of Ecosystem Studies, P.O. Box AB, Millbrook, New York 12545, USA.
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1015
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Sokolow SH, Foley P, Foley JE, Hastings A, Richardson LL. Editor's choice: Disease dynamics in marine metapopulations: modelling infectious diseases on coral reefs. J Appl Ecol 2009. [DOI: 10.1111/j.1365-2664.2009.01649.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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1016
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TRAVERS MARIE, BASUYAUX OLIVIER, LE GOÏC NELLY, HUCHETTE SYLVAIN, NICOLAS JEAN, KOKEN MARCEL, PAILLARD CHRISTINE. Influence of temperature and spawning effort on Haliotis tuberculata mortalities caused by Vibrio harveyi: an example of emerging vibriosis linked to global warming. GLOBAL CHANGE BIOLOGY 2009; 15:1365-1376. [DOI: 10.1111/j.1365-2486.2008.01764.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
AbstractSince 1998, Haliotis tuberculata mass mortalities have been occurring regularly in wild abalone populations in France during their reproductive period and in conjunction with seawater summer temperature maxima and Vibrio harveyi presence. To confirm the importance of bacterial exposure, temperature and reproductive status on abalone susceptibility, experimental infections via bath exposure were performed using abalone ranging from immature to reproductively mature. Ripe abalone were more susceptible to the bacterium than immature specimens (P<0.001), and a difference of only 1 °C in temperature had a highly significant impact on the mortalities (P<0.001). The natural mortalities that were surveyed during summer 2007 confirmed that recent epidemic losses of European abalone appeared in conjunction with host reproductive stress, elevated temperatures and presence of the pathogen V. harveyi. In view of the elevation of the mean summer temperatures observed in Brittany and Normandy over the last 25 years, this temperature‐dependent vibriosis represents a new case of emerging disease associated with global warming.
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1017
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Abstract
To date, ecologists and conservation biologists have focused much of their attention on the population and ecosystem effects of disease at regional scales and the role that diseases play in global species extinction. Far less research has been dedicated to identifying the effects that diseases can have on local scale species assemblages. We examined the role of infectious disease in structuring local biodiversity. Our intention was to illustrate how variable outcomes can occur by focusing on three case studies: the influence of chestnut blight on forest communities dominated by chestnut trees, the influence of red-spot disease on urchin barrens and kelp forests, and the influence of sylvatic plague on grassland communities inhabited by prairie dogs. Our findings reveal that at local scales infectious disease seems to play an important, though unpredictable, role in structuring species diversity. Through our case studies, we have shown that diseases can cause drastic population declines or local extirpations in keystone species, ecosystem engineers, and otherwise abundant species. These changes in local diversity may be very important, particularly when considered alongside potentially corresponding changes in community structure and function, and we believe that future efforts to understand the importance of disease to species diversity should have an increased focus on these local scales.
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Affiliation(s)
- Katherine F Smith
- Brown University, Ecology and Evolutionary Biology, Providence, RI 02912, USA.
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1018
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Sammarco PW, Strychar KB. Effects of Climate Change/Global Warming on Coral Reefs: Adaptation/Exaptation in Corals, Evolution in Zooxanthellae, and Biogeographic Shifts. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/15555270902905377] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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1019
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Kim Y, Powell EN. Effects of Climate Variability on Interannual Variation in Parasites, Pathologies, and Physiological Attributes of Bivalves from the U.S. East, Gulf, and West Coasts. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/15555270802708830] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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1020
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Barbosa A, Palacios MJ. Health of Antarctic birds: a review of their parasites, pathogens and diseases. Polar Biol 2009; 32:1095. [PMID: 32214635 PMCID: PMC7087846 DOI: 10.1007/s00300-009-0640-3] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Revised: 04/17/2009] [Accepted: 04/21/2009] [Indexed: 11/29/2022]
Abstract
Antarctic birds are not beyond the effects of parasites or pathogens. However, potential ecological consequences of wide-spread infections for bird populations in Antarctica have received little attention. In this paper, we review the information published about disease and parasites, and their effects on Antarctic birds. The information on host species, parasites and pathogens, and geographic regions is incomplete and data on ecological effects on the populations, including how birds respond to pathogens and parasites, are almost inexistent. We conclude that more research is needed to establish general patterns of spatial and temporal variation in pathogens and parasites, and to determine how such patterns could influence hosts. This information is crucial to limit the spread of outbreaks and may aid in the decision-making process should they occur.
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Affiliation(s)
- Andrés Barbosa
- Departamento de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Áridas, CSIC, C/General Segura, 1, 04001 Almeria, Spain
- Present Address: Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales, CSIC, C/José Gutiérrez Abascal, 2, 28006 Madrid, Spain
| | - María José Palacios
- Departamento de Ecología Funcional y Evolutiva, Estación Experimental de Zonas Áridas, CSIC, C/General Segura, 1, 04001 Almeria, Spain
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1021
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Sato Y, Bourne DG, Willis BL. Dynamics of seasonal outbreaks of black band disease in an assemblage of Montipora species at Pelorus Island (Great Barrier Reef, Australia). Proc Biol Sci 2009; 276:2795-803. [PMID: 19419991 DOI: 10.1098/rspb.2009.0481] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Recurring summer outbreaks of black band disease (BBD) on an inshore reef in the central Great Barrier Reef (GBR) constitute the first recorded BBD epizootic in the region. In a 2.7 year study of 485 colonies of Montipora species, BBD affected up to 10 per cent of colonies in the assemblage. Mean maximum abundance of BBD reached 16+/-6 colonies per 100 m(2) (n=3 quadrats, each 100 m(2)) in summer, and decreased to 0-1 colony per 100 m(2) in winter. On average, BBD lesions caused 40 per cent tissue loss and 5 per cent of infections led to whole colony mortality. BBD reappearance on previously infected colonies and continuous tissue loss after the BBD signs had disappeared suggest that the disease impacts are of longer duration than indicated by the presence of characteristic signs. Rates of new infections and linear progression of lesions were both positively correlated with seasonal fluctuations in sea water temperatures and light, suggesting that seasonal increases in these environmental parameters promote virulence of the disease. Overall, the impacts of BBD are greater than previously reported on the GBR and likely to escalate with ocean warming.
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Affiliation(s)
- Yui Sato
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville 4811, Australia.
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1022
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Jagai JS, Castronovo DA, Monchak J, Naumova EN. Seasonality of cryptosporidiosis: A meta-analysis approach. ENVIRONMENTAL RESEARCH 2009; 109:465-78. [PMID: 19328462 PMCID: PMC2732192 DOI: 10.1016/j.envres.2009.02.008] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Revised: 12/23/2008] [Accepted: 02/11/2009] [Indexed: 05/20/2023]
Abstract
OBJECTIVES We developed methodology for and conducted a meta-analysis to examine how seasonal patterns of cryptosporidiosis, a primarily waterborne diarrheal illness, relate to precipitation and temperature fluctuations worldwide. METHODS Monthly cryptosporidiosis data were abstracted from 61 published epidemiological studies that cover various climate regions based on the Köppen Climate Classification. Outcome data were supplemented with monthly aggregated ambient temperature and precipitation for each study location. We applied a linear mixed-effect model to relate the monthly normalized cryptosporidiosis incidence with normalized location-specific temperature and precipitation data. We also conducted a sub-analysis of associations between the Normalized Difference Vegetation Index (NDVI), a remote sensing measure for the combined effect of temperature and precipitation on vegetation, and cryptosporidiosis in Sub-Saharan Africa. RESULTS Overall, and after adjusting for distance from the equator, increases in temperature and precipitation predict an increase in cryptosporidiosis; the strengths of relationship vary by climate subcategory. In moist tropical locations, precipitation is a strong seasonal driver for cryptosporidiosis whereas temperature is in mid-latitude and temperate climates. When assessing lagged relationships, temperature and precipitation remain strong predictors. In Sub-Saharan Africa, after adjusting for distance from the equator, low NDVI values are predictive of an increase in cryptosporidiosis in the following month. DISCUSSION In this study we propose novel methodology to assess relationships between disease outcomes and meteorological data on a global scale. Our findings demonstrate that while climatic conditions typically define a pathogen habitat area, meteorological factors affect timing and intensity of seasonal outbreaks. Therefore, meteorological forecasts can be utilized to develop focused prevention programs for waterborne cryptosporidiosis.
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Affiliation(s)
- Jyotsna S Jagai
- Department of Public Health and Family Medicine, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, USA.
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1023
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McMahon SM, Dietze MC, Hersh MH, Moran EV, Clark JS. A Predictive Framework to Understand Forest Responses to Global Change. Ann N Y Acad Sci 2009; 1162:221-36. [DOI: 10.1111/j.1749-6632.2009.04495.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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1024
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Abstract
The unprecedented loss of biological diversity from anthropogenic causes has profound impacts on human health. One way that biodiversity loss threatens human health is by exacerbating risk and incidence of infectious diseases. This paper briefly reviews two zoonotic diseases--West Nile virus (WNV) illness and Lyme disease (LD)--in which high diversity in the community of vertebrate hosts for arthropod vectors strongly reduces human risk. In both cases, the primary reservoirs for the pathogen are species that dominate in human-impacted, low-diversity communities. As a result, the generalist vectors responsible for transmitting the pathogens to humans have relatively high feeding rates on these reservoirs, leading to high infection prevalence in mosquito (for WNV) and tick (for LD) vectors. In contrast, where native vertebrate diversity is high, mosquito and tick vectors evidently feed from a wider variety of hosts, most of which are poor reservoirs for the pathogens, resulting in lower infection prevalence. Protection of humans against exposure to zoonotic pathogens should be added to the list of utilitarian functions provided by high biodiversity.
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Affiliation(s)
- R S Ostfeld
- Cary Institute of Ecosystem Studies, Millbrook, NY 12545, USA.
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1025
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Graham CT, Harrod C. Implications of climate change for the fishes of the British Isles. JOURNAL OF FISH BIOLOGY 2009; 74:1143-1205. [PMID: 20735625 DOI: 10.1111/j.1095-8649.2009.02180.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Recent climatic change has been recorded across the globe. Although environmental change is a characteristic feature of life on Earth and has played a major role in the evolution and global distribution of biodiversity, predicted future rates of climatic change, especially in temperature, are such that they will exceed any that has occurred over recent geological time. Climate change is considered as a key threat to biodiversity and to the structure and function of ecosystems that may already be subject to significant anthropogenic stress. The current understanding of climate change and its likely consequences for the fishes of Britain and Ireland and the surrounding seas are reviewed through a series of case studies detailing the likely response of several marine, diadromous and freshwater fishes to climate change. Changes in climate, and in particular, temperature have and will continue to affect fish at all levels of biological organization: cellular, individual, population, species, community and ecosystem, influencing physiological and ecological processes in a number of direct, indirect and complex ways. The response of fishes and of other aquatic taxa will vary according to their tolerances and life stage and are complex and difficult to predict. Fishes may respond directly to climate-change-related shifts in environmental processes or indirectly to other influences, such as community-level interactions with other taxa. However, the ability to adapt to the predicted changes in climate will vary between species and between habitats and there will be winners and losers. In marine habitats, recent changes in fish community structure will continue as fishes shift their distributions relative to their temperature preferences. This may lead to the loss of some economically important cold-adapted species such as Gadus morhua and Clupea harengus from some areas around Britain and Ireland, and the establishment of some new, warm-adapted species. Increased temperatures are likely to favour cool-adapted (e.g. Perca fluviatilis) and warm-adapted freshwater fishes (e.g. roach Rutilus rutilus and other cyprinids) whose distribution and reproductive success may currently be constrained by temperature rather than by cold-adapted species (e.g. salmonids). Species that occur in Britain and Ireland that are at the edge of their distribution will be most affected, both negatively and positively. Populations of conservation importance (e.g.Salvelinus alpinus and Coregonus spp.) may decline irreversibly. However, changes in food-web dynamics and physiological adaptation, for example because of climate change, may obscure or alter predicted responses. The residual inertia in climate systems is such that even a complete cessation in emissions would still leave fishes exposed to continued climate change for at least half a century. Hence, regardless of the success or failure of programmes aimed at curbing climate change, major changes in fish communities can be expected over the next 50 years with a concomitant need to adapt management strategies accordingly.
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Affiliation(s)
- C T Graham
- Department of Zoology, Ecology and Plant Science, University College Cork, Ireland
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1026
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Harvell D, Altizer S, Cattadori IM, Harrington L, Weil E. Climate change and wildlife diseases: When does the host matter the most? Ecology 2009; 90:912-20. [DOI: 10.1890/08-0616.1] [Citation(s) in RCA: 225] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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1027
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1028
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Traill LW, Bradshaw CJA, Field HE, Brook BW. Climate Change Enhances the Potential Impact of Infectious Disease and Harvest on Tropical Waterfowl. Biotropica 2009. [DOI: 10.1111/j.1744-7429.2009.00508.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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1029
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Sussman M, Mieog JC, Doyle J, Victor S, Willis BL, Bourne DG. Vibrio zinc-metalloprotease causes photoinactivation of coral endosymbionts and coral tissue lesions. PLoS One 2009; 4:e4511. [PMID: 19225559 PMCID: PMC2637982 DOI: 10.1371/journal.pone.0004511] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Accepted: 01/01/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Coral diseases are emerging as a serious threat to coral reefs worldwide. Of nine coral infectious diseases, whose pathogens have been characterized, six are caused by agents from the family Vibrionacae, raising questions as to their origin and role in coral disease aetiology. METHODOLOGY/PRINCIPAL FINDINGS Here we report on a Vibrio zinc-metalloprotease causing rapid photoinactivation of susceptible Symbiodinium endosymbionts followed by lesions in coral tissue. Symbiodinium photosystem II inactivation was diagnosed by an imaging pulse amplitude modulation fluorometer in two bioassays, performed by exposing Symbiodinium cells and coral juveniles to non-inhibited and EDTA-inhibited supernatants derived from coral white syndrome pathogens. CONCLUSION/SIGNIFICANCE These findings demonstrate a common virulence factor from four phylogenetically related coral pathogens, suggesting that zinc-metalloproteases may play an important role in Vibrio pathogenicity in scleractinian corals.
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Affiliation(s)
- Meir Sussman
- ARC Centre of Excellence for Coral Reef Studies, and School of Marine and Tropical Biology, James Cook University, Townsville, Queensland, Australia.
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1030
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Hilker FM, Langlais M, Malchow H. The Allee effect and infectious diseases: extinction, multistability, and the (dis-)appearance of oscillations. Am Nat 2009; 173:72-88. [PMID: 19072071 DOI: 10.1086/593357] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Infectious diseases that affect their host on a long timescale can regulate the host population dynamics. Here we show that a strong Allee effect can lead to complex dynamics in simple epidemic models. Generally, the Allee effect renders a population bistable, but we also identify conditions for tri- or monostability. Moreover, the disease can destabilize endemic equilibria and induce sustained oscillations. These disappear again for high transmissibilities, with eventually vanishing host population. Disease-induced extinction is thus possible for density-dependent transmission and without any alternative reservoirs. The overall complexity suggests that the system is very sensitive to perturbations and control methods, even in parameter regions with a basic reproductive ratio far beyond R(0) = 1. This may have profound implications for biological conservation as well as pest management. We identify important threshold quantities and attribute the dynamical behavior to the joint interplay of a strong Allee effect and infection.
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Affiliation(s)
- Frank M Hilker
- Center for Mathematical Biology, Mathematical and Statistical Sciences, University of Alberta, 501 CAB, Edmonton, Alberta T6G 2G1, Canada
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1031
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Smith KF, Acevedo-Whitehouse K, Pedersen AB. The role of infectious diseases in biological conservation. Anim Conserv 2009. [DOI: 10.1111/j.1469-1795.2008.00228.x] [Citation(s) in RCA: 319] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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1032
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Flynn K, Weil E. Variability of aspergillosis inGorgonia ventalinain La Parguera, Puerto Rico. CARIBB J SCI 2009. [DOI: 10.18475/cjos.v45i2.a9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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1033
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Weil E, Croquer A, Urreiztieta I. Temporal variability and impact of coral diseases and bleaching in La Parguera, Puerto Rico from 2003–2007. CARIBB J SCI 2009. [DOI: 10.18475/cjos.v45i2.a10] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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1034
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Field IC, Meekan MG, Buckworth RC, Bradshaw CJA. Chapter 4. Susceptibility of sharks, rays and chimaeras to global extinction. ADVANCES IN MARINE BIOLOGY 2009; 56:275-363. [PMID: 19895977 DOI: 10.1016/s0065-2881(09)56004-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Marine biodiversity worldwide is under increasing threat, primarily as a result of over-harvesting, pollution and climate change. Chondrichthyan fishes (sharks, rays and chimaeras) have a perceived higher intrinsic risk of extinction compared to other fish. Direct fishing mortality has driven many declines, even though some smaller fisheries persist without associated declines. Mixed-species fisheries are of particular concern, as is illegal, unreported and unregulated (IUU) fishing. The lack of specific management and reporting mechanisms for the latter means that many chondrichthyans might already be susceptible to extinction from stochastic processes entirely unrelated to fishing pressure itself. Chondrichthyans might also suffer relatively more than other marine taxa from the effects of fishing and habitat loss and degradation given coastal habitat use for specific life stages. The effects of invasive species and pollution are as yet too poorly understood to predict their long-term role in affecting chondrichthyan population sizes. The spatial distribution of threatened chondrichthyan species under World Conservation Union (IUCN) Red List criteria are clustered mainly in (1) south-eastern South America; (2) western Europe and the Mediterranean; (3) western Africa; (4) South China Sea and Southeast Asia and (5) south-eastern Australia. To determine which ecological and life history traits predispose chondrichthyans to being IUCN Red-Listed, and to examine the role of particular human activities in exacerbating threat risk, we correlated extant marine species' Red List categorisation with available ecological (habitat type, temperature preference), life history (body length, range size) and human-relationship (whether commercially or game-fished, considered dangerous to humans) variables. Threat risk correlations were constructed using generalised linear mixed-effect models to account for phylogenetic relatedness. We also contrasted results for chondrichthyans to marine teleosts to test explicitly whether the former group is intrinsically more susceptible to extinction than fishes in general. Around 52% of chondrichthyans have been Red-Listed compared to only 8% of all marine teleosts; however, listed teleosts were in general placed more frequently into the higher-risk categories relative to chondrichthyans. IUCN threat risk in both taxa was positively correlated with body size and negatively correlated albeit weakly, with geographic range size. Even after accounting for the positive influence of size, Red-Listed teleosts were still more likely than chondrichthyans to be classified as threatened. We suggest that while sharks might not have necessarily experienced the same magnitude of deterministic decline as Red-Listed teleosts, their larger size and lower fecundity (not included in the analysis) predispose chondrichthyans to a higher risk of extinction overall. Removal of these large predators can elicit trophic cascades and destabilise the relative abundance of smaller species. Predator depletions can lead to permanent shifts in marine communities and alternate equilibrium states. Climate change might influence the phenology and physiology of some species, with the most probable response being changes in the timing of migrations and shifts in distribution. The synergistic effects among harvesting, habitat changes and climate-induced forcings are greatest for coastal chondrichthyans with specific habitat requirements and these are currently the most likely candidates for extinction. Management of shark populations must take into account the rate at which drivers of decline affect specific species. Only through the detailed collection of data describing demographic rates, habitat affinities, trophic linkages and geographic ranges, and how environmental stressors modify these, can extinction risk be more precisely estimated and reduced. The estimation of minimum viable population sizes, below which rapid extinction is more likely due to stochastic processes, is an important component of this endeavour and should accompany many of the current approaches used in shark management worldwide.
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Affiliation(s)
- Iain C Field
- School for Environmental Research, Institute of Advanced Studies, Charles Darwin University, Darwin, Northern Territory 0909, Australia
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1035
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1036
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Karraker NE, Ruthig GR. Effect of road deicing salt on the susceptibility of amphibian embryos to infection by water molds. ENVIRONMENTAL RESEARCH 2009; 109:40-45. [PMID: 18976747 DOI: 10.1016/j.envres.2008.09.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Revised: 09/01/2008] [Accepted: 09/04/2008] [Indexed: 05/27/2023]
Abstract
Some causative agents of amphibian declines act synergistically to impact individual amphibians and their populations. In particular, pathogenic water molds (aquatic oomycetes) interact with environmental stressors and increase mortality in amphibian embryos. We documented colonization of eggs of three amphibian species, the wood frog (Rana sylvatica), the green frog (Rana clamitans), and the spotted salamander (Ambystoma maculatum), by water molds in the field and examined the interactive effects of road deicing salt and water molds, two known sources of mortality for amphibian embryos, on two species, R. clamitans and A. maculatum in the laboratory. We found that exposure to water molds did not affect embryonic survivorship in either A. maculatum or R. clamitans, regardless of the concentration of road salt to which their eggs were exposed. Road salt decreased survivorship of A. maculatum, but not R. clamitans, and frequency of malformations increased significantly in both species at the highest salinity concentration. The lack of an effect of water molds on survival of embryos and no interaction between road salt and water molds indicates that observations of colonization of these eggs by water molds in the field probably represent a secondary invasion of unfertilized eggs or of embryos that had died of other causes. Given increasing salinization of freshwater habitats on several continents and the global distribution of water molds, our results suggest that some amphibian species may not be susceptible to the combined effects of these factors, permitting amphibian decline researchers to devote their attention to other potential causes.
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Affiliation(s)
- Nancy E Karraker
- Department of Environmental and Forest Biology, State University of New York College of Environmental Science and Forestry, Syracuse, NY, USA.
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1037
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Brugger K, Rubel F. Simulation of climate-change scenarios to explain Usutu-virus dynamics in Austria. Prev Vet Med 2009; 88:24-31. [PMID: 18715663 DOI: 10.1016/j.prevetmed.2008.06.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2007] [Revised: 06/09/2008] [Accepted: 06/30/2008] [Indexed: 11/28/2022]
Affiliation(s)
- Katharina Brugger
- Institute for Veterinary Public Health, University of Veterinary Medicine Vienna (VUW), Veterinärplatz 1, A-1210 Vienna, Austria
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1038
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Archie EA, Luikart G, Ezenwa VO. Infecting epidemiology with genetics: a new frontier in disease ecology. Trends Ecol Evol 2009; 24:21-30. [PMID: 19027985 DOI: 10.1016/j.tree.2008.08.008] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 08/07/2008] [Accepted: 08/12/2008] [Indexed: 10/21/2022]
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1039
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Ainsworth TD, Hoegh-Guldberg O, Leggat W. Imaging the fluorescence of marine invertebrates and their associated flora. J Microsc 2008; 232:197-9. [PMID: 19017217 DOI: 10.1111/j.1365-2818.2008.02089.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The cells and tissues of many marine invertebrates and their associated flora contain fluorescent pigments and proteins, many of which have been utilized commercially and provide marker molecules in other systems for fluorescence imaging technology. However, in the study of marine invertebrates and their symbioses these naturally occurring molecules have been seen to limit or confound fluorescence microscopy analyses. Here we demonstrate the endogenous fluorescence associated with two marine invertebrates (coral and foraminifera) and describe how these qualities can be utilized in fluorescence microanalyses. Understanding and imaging the diversity of fluorescent molecules provide insight into how fluorescence microscopy techniques can now be applied to these complex systems.
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Affiliation(s)
- T D Ainsworth
- Centre for Marine Studies, The University of Queensland, St. Lucia, QLD 4072, Australia.
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1040
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Antolin MF. Unpacking β: Within-Host Dynamics and the Evolutionary Ecology of Pathogen Transmission. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2008. [DOI: 10.1146/annurev.ecolsys.37.091305.110119] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Rather than being fixed, pathogen transmission varies and is thus an object of natural selection. I examine how opportunities for selection on pathogen transmission depend on (a) pathogen fitness, (b) genetic variability, and (c) forces acting at within- and between-host levels. The transmission rate, β, influences processes such as epidemic spread, postepidemic fade-outs, and low-level persistence. Complexity of infection processes within hosts leads to different transmission rates among hosts and between types of pathogens (viruses, bacteria, eukaryotic Protozoa). Generality emerges, however, by “unpacking” β into within- and between-host opportunities for selection. This is illustrated by evolutionary biology of the bacterium Yersinia pestis, which causes plague in mammals, remains highly virulent and is transmitted by multiple routes, including fleas and direct contacts with infected hosts. The strength of within-host selection is manifested through infectivity, replication, pathogenicity, and dissemination from hosts. At the between-host level, responses to selection are less predictable because of environmental variation, whereas vector-borne transmission (usually by arthropods) provides additional opportunities for selection and trade-offs between vectors and hosts. In subdivided host populations, selection favors transmission before local pathogen extinction occurs, but key components (e.g. infectious periods of hosts) are determined by within-host dynamics. Pathogen transmission is often viewed in the context of transmission-virulence trade-offs, but within-host dynamics may cause host damage unrelated to transmission, and thus transmission-virulence trade-offs are not universal.
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Affiliation(s)
- Michael F. Antolin
- Department of Biology, Colorado State University, Fort Collins, Colorado 80523
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1041
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The influence of climatic conditions on long-term changes in the helminth fauna of terrestrial molluscs and the implications for parasite transmission in southern England. J Helminthol 2008; 82:325-35. [DOI: 10.1017/s0022149x0802645x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractThe influence of climatic conditions on the prevalence and transmission of helminth parasites in a terrestrial mollusc population was studied in a grassland site in southern England between 1974 and 1983. Molluscs were sampled in each September of 5 years over this period (1974, 1976, 1979, 1981, 1983). Climatic conditions had a variable effect on parasite prevalence. Trematode sporocyst infections increased after wet summer and warm winter conditions and declined in hot, dry periods. Cestode infections increased after combined wet spring and summer weather and low winter temperatures, although trematode metacercariae and nematode infections were less likely to be influenced by climate. The effects on parasite transmission were undertaken by comparing parasite prevalences in the principal definitive hosts, the common shrew (Sorex araneus) and the wood mouse (Apodemus sylvaticus) in the same habitat over the period 1973–1983. Changes in parasite prevalences in the molluscan population were rarely replicated by changes in the small mammal population, except for trematode parasites in small mammals during a period of severe drought in 1976. These results suggest that only long-term persistent modifications in climate are likely to affect host–parasite dynamics.
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1042
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Smith TB, Nemeth RS, Blondeau J, Calnan JM, Kadison E, Herzlieb S. Assessing coral reef health across onshore to offshore stress gradients in the US Virgin Islands. MARINE POLLUTION BULLETIN 2008; 56:1983-1991. [PMID: 18834601 DOI: 10.1016/j.marpolbul.2008.08.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Revised: 08/10/2008] [Accepted: 08/18/2008] [Indexed: 05/26/2023]
Abstract
Managing the effects of anthropogenic disturbance on coral reefs is highly dependant on effective strategies to assess degradation and recovery. We used five years of field data in the US Virgin Islands to investigate coral reef response to a potential gradient of stress. We found that the prevalence of old partial mortality, bleaching, and all forms of coral health impairment (a novel category) increased with nearshore anthropogenic processes, such as a five-fold higher rate of clay and silt sedimentation. Other patterns of coral health, such as recent partial mortality, other diseases, and benthic cover, did not respond to this potential gradient of stress or their response could not be resolved at the frequency or scale of monitoring. We suggest that persistent signs of disturbance are more useful to short-term, non-intensive (annual) coral reef assessments, but more intensive (semi-annual) assessments are necessary to resolve patterns of transient signs of coral health impairment.
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Affiliation(s)
- T B Smith
- Center for Marine and Environmental Studies, University of the Virgin Islands, #2 John Brewer's Bay, St. Thomas, USVI 00802-9990, USA.
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1043
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Evaluating the links between climate, disease spread, and amphibian declines. Proc Natl Acad Sci U S A 2008; 105:17436-41. [PMID: 18987318 DOI: 10.1073/pnas.0806368105] [Citation(s) in RCA: 156] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human alteration of the environment has arguably propelled the Earth into its sixth mass extinction event and amphibians, the most threatened of all vertebrate taxa, are at the forefront. Many of the worldwide amphibian declines have been caused by the chytrid fungus, Batrachochytrium dendrobatidis (Bd), and two contrasting hypotheses have been proposed to explain these declines. Positive correlations between global warming and Bd-related declines sparked the chytrid-thermal-optimum hypothesis, which proposes that global warming increased cloud cover in warm years that drove the convergence of daytime and nighttime temperatures toward the thermal optimum for Bd growth. In contrast, the spatiotemporal-spread hypothesis states that Bd-related declines are caused by the introduction and spread of Bd, independent of climate change. We provide a rigorous test of these hypotheses by evaluating (i) whether cloud cover, temperature convergence, and predicted temperature-dependent Bd growth are significant positive predictors of amphibian extinctions in the genus Atelopus and (ii) whether spatial structure in the timing of these extinctions can be detected without making assumptions about the location, timing, or number of Bd emergences. We show that there is spatial structure to the timing of Atelopus spp. extinctions but that the cause of this structure remains equivocal, emphasizing the need for further molecular characterization of Bd. We also show that the reported positive multi-decade correlation between Atelopus spp. extinctions and mean tropical air temperature in the previous year is indeed robust, but the evidence that it is causal is weak because numerous other variables, including regional banana and beer production, were better predictors of these extinctions. Finally, almost all of our findings were opposite to the predictions of the chytrid-thermal-optimum hypothesis. Although climate change is likely to play an important role in worldwide amphibian declines, more convincing evidence is needed of a causal link.
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1044
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Nakazawa Y, Williams R, Peterson AT, Mead P, Staples E, Gage KL. Climate change effects on plague and tularemia in the United States. Vector Borne Zoonotic Dis 2008; 7:529-40. [PMID: 18047395 DOI: 10.1089/vbz.2007.0125] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Plague and tularemia are serious zoonotic diseases endemic to North America. We evaluated spatial patterns in their transmission in view of changing climates. First, we tested whether observed shifts since the 1960s are consistent with expected patterns of shift given known climate changes over that period. Then, we used general circulation model results summarizing global patterns of changing climates into the future to forecast likely shifts in patterns of transmission over the next 50 years. The results indicate that these diseases are indeed shifting in accord with patterns of climatic shift, but that overall geographic shifts will likely be subtle, with some northward movement of southern limits and possibly northward movement of northern limits as well.
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Affiliation(s)
- Yoshinori Nakazawa
- Natural History Museum and Biodiversity Research Center, The University of Kansas, Lawrence, Kansas 66045, USA.
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1045
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Back to the future: Developing hypotheses on the effects of climate change on ovine parasitic gastroenteritis from historical data. Vet Parasitol 2008; 158:73-84. [DOI: 10.1016/j.vetpar.2008.08.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 08/15/2008] [Accepted: 08/18/2008] [Indexed: 11/24/2022]
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1046
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Woodhams DC, Alford RA, Briggs CJ, Johnson M, Rollins-Smith LA. Life-history trade-offs influence disease in changing climates: strategies of an amphibian pathogen. Ecology 2008; 89:1627-39. [PMID: 18589527 DOI: 10.1890/06-1842.1] [Citation(s) in RCA: 177] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Life-history trade-offs allow many animals to maintain reproductive fitness across a range of climatic conditions. When used by parasites and pathogens, these strategies may influence patterns of disease in changing climates. The chytrid fungus, Batrachochytrium dendrobatidis, is linked to global declines of amphibian populations. Short-term growth in culture is maximal at 17 degrees-25 degrees C. This has been used in an argument that global warming, which increases the time that amphibians spend at these temperatures in cloud-covered montane environments, has led to extinctions. Here we show that the amphibian chytrid responds to decreasing temperatures with trade-offs that increase fecundity as maturation rate slows and increase infectivity as growth decreases. At 17 degrees-25 degrees C, infectious zoospores encyst (settle and develop a cell wall) and develop into the zoospore-producing stage (zoosporangium) faster, while at 7 degrees-10 degrees C, greater numbers of zoospores are produced per zoosporangium; these remain infectious for a longer period of time. We modeled the population growth of B. dendrobatidis through time at various temperatures using delayed differential equations and observational data for four parameters: developmental rate of thalli, fecundity, rate of zoospore encystment, and rate of zoospore survival. From the models, it is clear that life-history trade-offs allow B. dendrobatidis to maintain a relatively high long-term growth rate at low temperatures, so that it maintains high fitness across a range of temperatures. When a seven-day cold shock is simulated, the outcome is intermediate between the two constant temperature regimes, and in culture, a sudden drop in temperature induces zoospore release. These trade-offs can be ecologically important for a variety of organisms with complex life histories, including pathogenic microorganisms. The effect of temperature on amphibian mortality will depend on the interaction between fungal growth and host immune function and will be modified by host ecology, behavior, and life history. These results demonstrate that B. dendrobatidis populations can grow at high rates across a broad range of environmental temperatures and help to explain why it is so successful in cold montane environments.
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Affiliation(s)
- Douglas C Woodhams
- Department of Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee 37232, USA.
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1047
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Efrony R, Atad I, Rosenberg E. Phage therapy of coral white plague disease: properties of phage BA3. Curr Microbiol 2008; 58:139-45. [PMID: 18923867 DOI: 10.1007/s00284-008-9290-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 08/19/2008] [Accepted: 09/17/2008] [Indexed: 10/21/2022]
Abstract
The bacteriophage BA3 multiplies in and lyses the coral pathogen Thalassomonas loyana. The complete genome of phage BA3 was sequenced; it contains 47 open reading frames with a 40.9% G + C content. Phage BA3 adsorbed to its starved host in seawater with a k = 1.0 x 10(-6) phage ml(-1) min(-1). Phage therapy of coral disease in aquarium experiments was successful when the phage was added at the same time as the pathogen or 1 day later, but failed to protect the coral when added 2 days after bacterial infection. When the phages were added 1 day after coral infection, the phage titer increased about 100-fold and remained present in the aquarium water throughout the 37-day experiment. At the end of the experiment, the concentration of phages associated with the corals was 2.5 +/- 0.5 x 10(4) per cm(2) of coral surface. Corals that were infected with the pathogen and treated with phage did not transmit the disease to healthy corals.
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Affiliation(s)
- Rotem Efrony
- Department of Molecular Microbiology & Biotechnology, Tel Aviv University, Ramat Aviv, Israel
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Thomas T, Evans FF, Schleheck D, Mai-Prochnow A, Burke C, Penesyan A, Dalisay DS, Stelzer-Braid S, Saunders N, Johnson J, Ferriera S, Kjelleberg S, Egan S. Analysis of the Pseudoalteromonas tunicata genome reveals properties of a surface-associated life style in the marine environment. PLoS One 2008; 3:e3252. [PMID: 18813346 PMCID: PMC2536512 DOI: 10.1371/journal.pone.0003252] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2008] [Accepted: 08/21/2008] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Colonisation of sessile eukaryotic host surfaces (e.g. invertebrates and seaweeds) by bacteria is common in the marine environment and is expected to create significant inter-species competition and other interactions. The bacterium Pseudoalteromonas tunicata is a successful competitor on marine surfaces owing primarily to its ability to produce a number of inhibitory molecules. As such P. tunicata has become a model organism for the studies into processes of surface colonisation and eukaryotic host-bacteria interactions. METHODOLOGY/PRINCIPAL FINDINGS To gain a broader understanding into the adaptation to a surface-associated life-style, we have sequenced and analysed the genome of P. tunicata and compared it to the genomes of closely related strains. We found that the P. tunicata genome contains several genes and gene clusters that are involved in the production of inhibitory compounds against surface competitors and secondary colonisers. Features of P. tunicata's oxidative stress response, iron scavenging and nutrient acquisition show that the organism is well adapted to high-density communities on surfaces. Variation of the P. tunicata genome is suggested by several landmarks of genetic rearrangements and mobile genetic elements (e.g. transposons, CRISPRs, phage). Surface attachment is likely to be mediated by curli, novel pili, a number of extracellular polymers and potentially other unexpected cell surface proteins. The P. tunicata genome also shows a utilisation pattern of extracellular polymers that would avoid a degradation of its recognised hosts, while potentially causing detrimental effects on other host types. In addition, the prevalence of recognised virulence genes suggests that P. tunicata has the potential for pathogenic interactions. CONCLUSIONS/SIGNIFICANCE The genome analysis has revealed several physiological features that would provide P. tunciata with competitive advantage against other members of the surface-associated community. We have also identified properties that could mediate interactions with surfaces other than its currently recognised hosts. This together with the detection of known virulence genes leads to the hypothesis that P. tunicata maintains a carefully regulated balance between beneficial and detrimental interactions with a range of host surfaces.
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Affiliation(s)
- Torsten Thomas
- Centre of Marine Bio-Innovation and School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, New South Wales, Australia.
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ONeill GA, Hamann A, Wang T. Accounting for population variation improves estimates of the impact of climate change on species growth and distribution. J Appl Ecol 2008. [DOI: 10.1111/j.1365-2664.2008.01472.x] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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