Limits...
Disentangling host, pathogen, and environmental determinants of a recently emerged wildlife disease: lessons from the first 15 years of amphibian chytridiomycosis research.

James TY, Toledo LF, Rödder D, da Silva Leite D, Belasen AM, Betancourt-Román CM, Jenkinson TS, Soto-Azat C, Lambertini C, Longo AV, Ruggeri J, Collins JP, Burrowes PA, Lips KR, Zamudio KR, Longcore JE - Ecol Evol (2015)

Bottom Line: We explore factors associated with variance in severity of epizootics focusing on the disease triangle of host susceptibility, pathogen virulence, and environment.Instead of focusing on pathogen "hot spots," we need to identify pathogen "cold spots" so that we can better understand what limits the pathogen's distribution.Finally, we introduce the concept of "the Ghost of Epizootics Past" to discuss expected patterns in postepizootic host communities.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan 48109.

ABSTRACT
The amphibian fungal disease chytridiomycosis, which affects species across all continents, recently emerged as one of the greatest threats to biodiversity. Yet, many aspects of the basic biology and epidemiology of the pathogen, Batrachochytrium dendrobatidis (Bd), are still unknown, such as when and from where did Bd emerge and what is its true ecological niche? Here, we review the ecology and evolution of Bd in the Americas and highlight controversies that make this disease so enigmatic. We explore factors associated with variance in severity of epizootics focusing on the disease triangle of host susceptibility, pathogen virulence, and environment. Reevaluating the causes of the panzootic is timely given the wealth of data on Bd prevalence across hosts and communities and the recent discoveries suggesting co-evolutionary potential of hosts and Bd. We generate a new species distribution model for Bd in the Americas based on over 30,000 records and suggest a novel future research agenda. Instead of focusing on pathogen "hot spots," we need to identify pathogen "cold spots" so that we can better understand what limits the pathogen's distribution. Finally, we introduce the concept of "the Ghost of Epizootics Past" to discuss expected patterns in postepizootic host communities.

No MeSH data available.


Related in: MedlinePlus

Positive records of Batrachochytrium dendrobatidis and potential distribution of the fungus according to an ensemble species distribution model. Warmer colors indicate higher probability of environmental suitability. Areas exceeding the environmental training range of the SDM are indicated in gray.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4588650&req=5

ece31672-fig-0002: Positive records of Batrachochytrium dendrobatidis and potential distribution of the fungus according to an ensemble species distribution model. Warmer colors indicate higher probability of environmental suitability. Areas exceeding the environmental training range of the SDM are indicated in gray.

Mentions: Since its discovery, much effort has been spent on mapping the spatial distribution of Bd to provide a landscape view of areas with high environmental suitability. Olson et al. (2013) provided the most recent overview of the global distribution of Bd, analyzing the host and geographic patterns of 4281 individually swabbed frogs from 56 countries, of which 1814 (48%) were Bd positive by molecular detection methods. Using logistic regression, Olson et al. examined associations between Bd occurrence at a site and latitude, elevation, biome, amphibian species richness, and global temperature and precipitation metrics. While these methods are powerful to detect environmental correlations, they cannot determine whether an unsampled site may be environmentally suitable for Bd. Species distribution models (SDMs), on the other hand, predict the geographic extent of a species and identify the contribution of habitat parameters in explaining that distribution. Rödder et al. (2009) and Liu et al. (2013) developed the first Bd SDMs that were global in scope, based on 365 and 1829 Bd records, respectively. Here we present a comprehensive SDM for Bd in the Americas (Fig. 2), based on 6071 Bd positives from 30,382 analyzed swabs from fieldwork of the authors plus an intensive literature review (Box 2). The most intensively surveyed areas include western and eastern United States, Costa Rica, Panama, Puerto Rico, the Andes, and the Brazilian Atlantic Forest. Knowledge gaps include the central United States, northern Mexico, the Amazon Basin, the Brazilian Cerrado and Pantanal, and large regions in Argentina and Bolivia (Fig. 2).


Disentangling host, pathogen, and environmental determinants of a recently emerged wildlife disease: lessons from the first 15 years of amphibian chytridiomycosis research.

James TY, Toledo LF, Rödder D, da Silva Leite D, Belasen AM, Betancourt-Román CM, Jenkinson TS, Soto-Azat C, Lambertini C, Longo AV, Ruggeri J, Collins JP, Burrowes PA, Lips KR, Zamudio KR, Longcore JE - Ecol Evol (2015)

Positive records of Batrachochytrium dendrobatidis and potential distribution of the fungus according to an ensemble species distribution model. Warmer colors indicate higher probability of environmental suitability. Areas exceeding the environmental training range of the SDM are indicated in gray.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4588650&req=5

ece31672-fig-0002: Positive records of Batrachochytrium dendrobatidis and potential distribution of the fungus according to an ensemble species distribution model. Warmer colors indicate higher probability of environmental suitability. Areas exceeding the environmental training range of the SDM are indicated in gray.
Mentions: Since its discovery, much effort has been spent on mapping the spatial distribution of Bd to provide a landscape view of areas with high environmental suitability. Olson et al. (2013) provided the most recent overview of the global distribution of Bd, analyzing the host and geographic patterns of 4281 individually swabbed frogs from 56 countries, of which 1814 (48%) were Bd positive by molecular detection methods. Using logistic regression, Olson et al. examined associations between Bd occurrence at a site and latitude, elevation, biome, amphibian species richness, and global temperature and precipitation metrics. While these methods are powerful to detect environmental correlations, they cannot determine whether an unsampled site may be environmentally suitable for Bd. Species distribution models (SDMs), on the other hand, predict the geographic extent of a species and identify the contribution of habitat parameters in explaining that distribution. Rödder et al. (2009) and Liu et al. (2013) developed the first Bd SDMs that were global in scope, based on 365 and 1829 Bd records, respectively. Here we present a comprehensive SDM for Bd in the Americas (Fig. 2), based on 6071 Bd positives from 30,382 analyzed swabs from fieldwork of the authors plus an intensive literature review (Box 2). The most intensively surveyed areas include western and eastern United States, Costa Rica, Panama, Puerto Rico, the Andes, and the Brazilian Atlantic Forest. Knowledge gaps include the central United States, northern Mexico, the Amazon Basin, the Brazilian Cerrado and Pantanal, and large regions in Argentina and Bolivia (Fig. 2).

Bottom Line: We explore factors associated with variance in severity of epizootics focusing on the disease triangle of host susceptibility, pathogen virulence, and environment.Instead of focusing on pathogen "hot spots," we need to identify pathogen "cold spots" so that we can better understand what limits the pathogen's distribution.Finally, we introduce the concept of "the Ghost of Epizootics Past" to discuss expected patterns in postepizootic host communities.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan 48109.

ABSTRACT
The amphibian fungal disease chytridiomycosis, which affects species across all continents, recently emerged as one of the greatest threats to biodiversity. Yet, many aspects of the basic biology and epidemiology of the pathogen, Batrachochytrium dendrobatidis (Bd), are still unknown, such as when and from where did Bd emerge and what is its true ecological niche? Here, we review the ecology and evolution of Bd in the Americas and highlight controversies that make this disease so enigmatic. We explore factors associated with variance in severity of epizootics focusing on the disease triangle of host susceptibility, pathogen virulence, and environment. Reevaluating the causes of the panzootic is timely given the wealth of data on Bd prevalence across hosts and communities and the recent discoveries suggesting co-evolutionary potential of hosts and Bd. We generate a new species distribution model for Bd in the Americas based on over 30,000 records and suggest a novel future research agenda. Instead of focusing on pathogen "hot spots," we need to identify pathogen "cold spots" so that we can better understand what limits the pathogen's distribution. Finally, we introduce the concept of "the Ghost of Epizootics Past" to discuss expected patterns in postepizootic host communities.

No MeSH data available.


Related in: MedlinePlus