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Continental-scale patterns of pathogen prevalence: a case study on the corncrake.

Fourcade Y, Keišs O, Richardson DS, Secondi J - Evol Appl (2014)

Bottom Line: To determine how much variation in the pathogens observed among fragmented populations is caused by ecological factors, one needs to examine systems where host genetic diversity is consistent among the populations, thus controlling for any potentially confounding genetic effects.This likely reveals a possible impact of local agriculture intensity, which reduced host population densities in Western Europe and, potentially, insect vector abundance, thus reducing the transmission of pathogens.We conclude that in the corncrake system, where metapopulation dynamics resulted in variations in local census population sizes, but not in the genetic impoverishment of these populations, anthropogenic activity has led to a reduction in host populations and pathogen prevalence.

View Article: PubMed Central - PubMed

Affiliation: Université d'Angers, GECCO Angers, France ; Centre for Ecology, Evolution and Conservation, School of Biological Sciences, University of East Anglia Norwich, UK.

ABSTRACT
Pathogen infections can represent a substantial threat to wild populations, especially those already limited in size. To determine how much variation in the pathogens observed among fragmented populations is caused by ecological factors, one needs to examine systems where host genetic diversity is consistent among the populations, thus controlling for any potentially confounding genetic effects. Here, we report geographic variation in haemosporidian infection among European populations of corncrake. This species now occurs in fragmented populations, but there is little genetic structure and equally high levels of genetic diversity among these populations. We observed a longitudinal gradient of prevalence from western to Eastern Europe negatively correlated with national agricultural yield, but positively correlated with corncrake census population sizes when only the most widespread lineage is considered. This likely reveals a possible impact of local agriculture intensity, which reduced host population densities in Western Europe and, potentially, insect vector abundance, thus reducing the transmission of pathogens. We conclude that in the corncrake system, where metapopulation dynamics resulted in variations in local census population sizes, but not in the genetic impoverishment of these populations, anthropogenic activity has led to a reduction in host populations and pathogen prevalence.

No MeSH data available.


Related in: MedlinePlus

Geographic distribution of malaria prevalence per population across nine European populations of corncrake (Crex crex). The size of each circle is function of the number of samples from that location (minimum: Russia, 20 samples; maximum: Latvia, 71 samples).
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fig01: Geographic distribution of malaria prevalence per population across nine European populations of corncrake (Crex crex). The size of each circle is function of the number of samples from that location (minimum: Russia, 20 samples; maximum: Latvia, 71 samples).

Mentions: We found no evidence of cross-sample contamination or failed amplification based on the negative and positive controls. Observed overall prevalence across all populations was 10% (36/354 birds). Prevalence varied considerably among populations across Europe (Range = 0–30%, χ² = 18.41, P = 0.018) exhibiting a spatial gradient from south–west (France, 3.3% prevalence) to north–east (Russia, 30% prevalence) (Fig.1, linear regression against longitude: F1,7 = 13.00, adjusted R² = 0.60, P = 0.01, linear regression against latitude: F1,7 = 1.06, adjusted R² = 0.01, P = 0.34).


Continental-scale patterns of pathogen prevalence: a case study on the corncrake.

Fourcade Y, Keišs O, Richardson DS, Secondi J - Evol Appl (2014)

Geographic distribution of malaria prevalence per population across nine European populations of corncrake (Crex crex). The size of each circle is function of the number of samples from that location (minimum: Russia, 20 samples; maximum: Latvia, 71 samples).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231594&req=5

fig01: Geographic distribution of malaria prevalence per population across nine European populations of corncrake (Crex crex). The size of each circle is function of the number of samples from that location (minimum: Russia, 20 samples; maximum: Latvia, 71 samples).
Mentions: We found no evidence of cross-sample contamination or failed amplification based on the negative and positive controls. Observed overall prevalence across all populations was 10% (36/354 birds). Prevalence varied considerably among populations across Europe (Range = 0–30%, χ² = 18.41, P = 0.018) exhibiting a spatial gradient from south–west (France, 3.3% prevalence) to north–east (Russia, 30% prevalence) (Fig.1, linear regression against longitude: F1,7 = 13.00, adjusted R² = 0.60, P = 0.01, linear regression against latitude: F1,7 = 1.06, adjusted R² = 0.01, P = 0.34).

Bottom Line: To determine how much variation in the pathogens observed among fragmented populations is caused by ecological factors, one needs to examine systems where host genetic diversity is consistent among the populations, thus controlling for any potentially confounding genetic effects.This likely reveals a possible impact of local agriculture intensity, which reduced host population densities in Western Europe and, potentially, insect vector abundance, thus reducing the transmission of pathogens.We conclude that in the corncrake system, where metapopulation dynamics resulted in variations in local census population sizes, but not in the genetic impoverishment of these populations, anthropogenic activity has led to a reduction in host populations and pathogen prevalence.

View Article: PubMed Central - PubMed

Affiliation: Université d'Angers, GECCO Angers, France ; Centre for Ecology, Evolution and Conservation, School of Biological Sciences, University of East Anglia Norwich, UK.

ABSTRACT
Pathogen infections can represent a substantial threat to wild populations, especially those already limited in size. To determine how much variation in the pathogens observed among fragmented populations is caused by ecological factors, one needs to examine systems where host genetic diversity is consistent among the populations, thus controlling for any potentially confounding genetic effects. Here, we report geographic variation in haemosporidian infection among European populations of corncrake. This species now occurs in fragmented populations, but there is little genetic structure and equally high levels of genetic diversity among these populations. We observed a longitudinal gradient of prevalence from western to Eastern Europe negatively correlated with national agricultural yield, but positively correlated with corncrake census population sizes when only the most widespread lineage is considered. This likely reveals a possible impact of local agriculture intensity, which reduced host population densities in Western Europe and, potentially, insect vector abundance, thus reducing the transmission of pathogens. We conclude that in the corncrake system, where metapopulation dynamics resulted in variations in local census population sizes, but not in the genetic impoverishment of these populations, anthropogenic activity has led to a reduction in host populations and pathogen prevalence.

No MeSH data available.


Related in: MedlinePlus