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No Observed Effect of Landscape Fragmentation on Pathogen Infection Prevalence in Blacklegged Ticks (Ixodes scapularis) in the Northeastern United States.

Zolnik CP, Falco RC, Kolokotronis SO, Daniels TJ - PLoS ONE (2015)

Bottom Line: Pathogen prevalence within blacklegged ticks (Ixodes scapularis Say, 1821) tends to vary across sites and geographic regions, but the underlying causes of this variation are not well understood.Although the Lyme disease transmission cycle is often cited as a model for this "dilution effect hypothesis", little empirical evidence exists to support that claim.Our results do not support the dilution effect hypothesis for either pathogen and are in agreement with the few studies to date that have tested this idea using either a landscape proxy or direct measures of host biodiversity.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Fordham University, Bronx, New York, United States of America; Vector Ecology Laboratory, Louis Calder Center-Biological Field Station, Fordham University, Armonk, New York, United States of America.

ABSTRACT
Pathogen prevalence within blacklegged ticks (Ixodes scapularis Say, 1821) tends to vary across sites and geographic regions, but the underlying causes of this variation are not well understood. Efforts to understand the ecology of Lyme disease have led to the proposition that sites with higher host diversity will result in lower disease risk due to an increase in the abundance of inefficient reservoir species relative to the abundance of species that are highly competent reservoirs. Although the Lyme disease transmission cycle is often cited as a model for this "dilution effect hypothesis", little empirical evidence exists to support that claim. Here we tested the dilution effect hypothesis for two pathogens transmitted by the blacklegged tick along an urban-to-rural gradient in the northeastern United States using landscape fragmentation as a proxy for host biodiversity. Percent impervious surface and habitat fragment size around each site were determined to assess the effect of landscape fragmentation on nymphal blacklegged tick infection with Borrelia burgdorferi and Anaplasma phagocytophilum. Our results do not support the dilution effect hypothesis for either pathogen and are in agreement with the few studies to date that have tested this idea using either a landscape proxy or direct measures of host biodiversity.

No MeSH data available.


Related in: MedlinePlus

Tick collection localities in New York and Connecticut.Locations of the fourteen sampling sites used in this study across four counties in southern New York and western Connecticut with land cover types from the 2011 National Land Cover Database (NLCD) [43]. Site locality information is consistent with Table 1. Site markers are not drawn to scale. Inset shows a map of the region at state level for reference. Box indicates magnified area.
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pone.0139473.g001: Tick collection localities in New York and Connecticut.Locations of the fourteen sampling sites used in this study across four counties in southern New York and western Connecticut with land cover types from the 2011 National Land Cover Database (NLCD) [43]. Site locality information is consistent with Table 1. Site markers are not drawn to scale. Inset shows a map of the region at state level for reference. Box indicates magnified area.

Mentions: Fourteen forested sites along a 115-km urban-to-rural gradient were selected for this study [41]. This urban-to-rural gradient runs from New York City to rural western Connecticut [41] and sites for this study were located within three counties in southern New York (Bronx, Westchester, and Putnam) and one county in western Connecticut (Litchfield) (Fig 1). Bronx and southern Westchester counties have forests that are heavily fragmented and a comparatively large fraction of the land is covered with impervious surface. This fragmentation and imperviousness decreases into northern Westchester, Putnam and Litchfield counties [41]. Blacklegged ticks in this region are highly prevalent and the area is endemic for both B. burgdorferi and A. phagocytophilum [1, 2, 7, 42]. All sampling sites were located in state, county, or city public lands and were comprised of deciduous forest cover; sampling locations were at least 7.5 km from each other. Appropriate scientific collection permits were obtained from all relevant agencies.


No Observed Effect of Landscape Fragmentation on Pathogen Infection Prevalence in Blacklegged Ticks (Ixodes scapularis) in the Northeastern United States.

Zolnik CP, Falco RC, Kolokotronis SO, Daniels TJ - PLoS ONE (2015)

Tick collection localities in New York and Connecticut.Locations of the fourteen sampling sites used in this study across four counties in southern New York and western Connecticut with land cover types from the 2011 National Land Cover Database (NLCD) [43]. Site locality information is consistent with Table 1. Site markers are not drawn to scale. Inset shows a map of the region at state level for reference. Box indicates magnified area.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4591970&req=5

pone.0139473.g001: Tick collection localities in New York and Connecticut.Locations of the fourteen sampling sites used in this study across four counties in southern New York and western Connecticut with land cover types from the 2011 National Land Cover Database (NLCD) [43]. Site locality information is consistent with Table 1. Site markers are not drawn to scale. Inset shows a map of the region at state level for reference. Box indicates magnified area.
Mentions: Fourteen forested sites along a 115-km urban-to-rural gradient were selected for this study [41]. This urban-to-rural gradient runs from New York City to rural western Connecticut [41] and sites for this study were located within three counties in southern New York (Bronx, Westchester, and Putnam) and one county in western Connecticut (Litchfield) (Fig 1). Bronx and southern Westchester counties have forests that are heavily fragmented and a comparatively large fraction of the land is covered with impervious surface. This fragmentation and imperviousness decreases into northern Westchester, Putnam and Litchfield counties [41]. Blacklegged ticks in this region are highly prevalent and the area is endemic for both B. burgdorferi and A. phagocytophilum [1, 2, 7, 42]. All sampling sites were located in state, county, or city public lands and were comprised of deciduous forest cover; sampling locations were at least 7.5 km from each other. Appropriate scientific collection permits were obtained from all relevant agencies.

Bottom Line: Pathogen prevalence within blacklegged ticks (Ixodes scapularis Say, 1821) tends to vary across sites and geographic regions, but the underlying causes of this variation are not well understood.Although the Lyme disease transmission cycle is often cited as a model for this "dilution effect hypothesis", little empirical evidence exists to support that claim.Our results do not support the dilution effect hypothesis for either pathogen and are in agreement with the few studies to date that have tested this idea using either a landscape proxy or direct measures of host biodiversity.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, Fordham University, Bronx, New York, United States of America; Vector Ecology Laboratory, Louis Calder Center-Biological Field Station, Fordham University, Armonk, New York, United States of America.

ABSTRACT
Pathogen prevalence within blacklegged ticks (Ixodes scapularis Say, 1821) tends to vary across sites and geographic regions, but the underlying causes of this variation are not well understood. Efforts to understand the ecology of Lyme disease have led to the proposition that sites with higher host diversity will result in lower disease risk due to an increase in the abundance of inefficient reservoir species relative to the abundance of species that are highly competent reservoirs. Although the Lyme disease transmission cycle is often cited as a model for this "dilution effect hypothesis", little empirical evidence exists to support that claim. Here we tested the dilution effect hypothesis for two pathogens transmitted by the blacklegged tick along an urban-to-rural gradient in the northeastern United States using landscape fragmentation as a proxy for host biodiversity. Percent impervious surface and habitat fragment size around each site were determined to assess the effect of landscape fragmentation on nymphal blacklegged tick infection with Borrelia burgdorferi and Anaplasma phagocytophilum. Our results do not support the dilution effect hypothesis for either pathogen and are in agreement with the few studies to date that have tested this idea using either a landscape proxy or direct measures of host biodiversity.

No MeSH data available.


Related in: MedlinePlus