2004
Eisen, Rebecca J.; Eisen, Lars; Lane, Robert S.
Habitat-related variation in infestation of lizards and rodents with Ixodes ticks in dense woodlands Journal Article
In: Experimental and Applied Acarology, vol. 33, no. 3, pp. 215-233, 2004, ISSN: 1572-9702.
Abstract | Links | BibTeX | Tags: Borrelia burgdorferi, California, Infestation, Ixodes pacificus, Lizards, Rodents
@article{Eisen2004,
title = {Habitat-related variation in infestation of lizards and rodents with Ixodes ticks in dense woodlands},
author = {Rebecca J. Eisen and Lars Eisen and Robert S. Lane},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Habitat-related-variation-in-infestation-of-lizards-and-rodents-with-Ixodes-ticks-in-dense-woodlands-in-Mendocino-County-California_Eisen.pdf},
doi = {10.1023/B:APPA.0000032954.71165.9e},
issn = {1572-9702},
year = {2004},
date = {2004-07-01},
journal = {Experimental and Applied Acarology},
volume = {33},
number = {3},
pages = {215-233},
abstract = {During the spring and early summer of 2002, we examined the relative importance of Borrelia-refractory lizards (Sceloporus occidentalis, Elgaria spp.) versus potential Borrelia burgdorferi sensu lato (s.l.)-reservoirs (rodents) as hosts for Ixodes pacificus immatures in 14 woodland areas (six oak, five mixed oak/Douglas fir, and three redwood/tanoak areas) distributed throughout Mendocino County, California. Lizards were estimated to serve as hosts for 93–98% of all larvae and ≥99.6% of all nymphs infesting lizards or rodents in oak woodlands and oak/Douglas fir sites in the southern part of the county. In redwood/tanoak woodlands and oak/Douglas fir sites in northern Mendocino County, the contribution of rodents to larval feedings reached 36–69% but lizards still accounted for 94–100% of nymphal bloodmeals. From late April to mid-June, I. pacificus larvae were recovered from 95 to 96% of lizards and dusky-footed woodrats (Neotoma fuscipes) and from 59% of Peromyscus spp. mice. In contrast, 99% of lizards but few woodrats (15%) and none of the mice were infested by nymphs. Comparisons of tick loads for 19 lizard–Peromyscus spp. mouse pairings, where the lizard and mouse were captured within 10 m of each other, revealed that the lizards harbored 36 times more larvae and >190 times more nymphs than the mice. In oak woodlands, loads of I. pacificus larvae decreased from late April/early May to late June for S. occidentalis lizards but increased for Peromyscus spp. mice. We conclude that the relative utilization of Borrelia-refractory lizards, as compared to rodents, by I. pacificus larvae was far higher in dry oak woodlands than in moister habitats such as redwood/tanoak and oak/Douglas fir woodlands in northern Mendocino County. Non-lizard-infesting potential enzootic vectors of B. burgdorferi s.l. (I. angustus and I. spinipalpis) were recorded from rodents in three of six oak woodland areas, two of five oak/Douglas fir woodland areas, and two of three redwood/tanoak woodland areas.},
keywords = {Borrelia burgdorferi, California, Infestation, Ixodes pacificus, Lizards, Rodents},
pubstate = {published},
tppubtype = {article}
}
During the spring and early summer of 2002, we examined the relative importance of Borrelia-refractory lizards (Sceloporus occidentalis, Elgaria spp.) versus potential Borrelia burgdorferi sensu lato (s.l.)-reservoirs (rodents) as hosts for Ixodes pacificus immatures in 14 woodland areas (six oak, five mixed oak/Douglas fir, and three redwood/tanoak areas) distributed throughout Mendocino County, California. Lizards were estimated to serve as hosts for 93–98% of all larvae and ≥99.6% of all nymphs infesting lizards or rodents in oak woodlands and oak/Douglas fir sites in the southern part of the county. In redwood/tanoak woodlands and oak/Douglas fir sites in northern Mendocino County, the contribution of rodents to larval feedings reached 36–69% but lizards still accounted for 94–100% of nymphal bloodmeals. From late April to mid-June, I. pacificus larvae were recovered from 95 to 96% of lizards and dusky-footed woodrats (Neotoma fuscipes) and from 59% of Peromyscus spp. mice. In contrast, 99% of lizards but few woodrats (15%) and none of the mice were infested by nymphs. Comparisons of tick loads for 19 lizard–Peromyscus spp. mouse pairings, where the lizard and mouse were captured within 10 m of each other, revealed that the lizards harbored 36 times more larvae and >190 times more nymphs than the mice. In oak woodlands, loads of I. pacificus larvae decreased from late April/early May to late June for S. occidentalis lizards but increased for Peromyscus spp. mice. We conclude that the relative utilization of Borrelia-refractory lizards, as compared to rodents, by I. pacificus larvae was far higher in dry oak woodlands than in moister habitats such as redwood/tanoak and oak/Douglas fir woodlands in northern Mendocino County. Non-lizard-infesting potential enzootic vectors of B. burgdorferi s.l. (I. angustus and I. spinipalpis) were recorded from rodents in three of six oak woodland areas, two of five oak/Douglas fir woodland areas, and two of three redwood/tanoak woodland areas.
2003
Eisen, Rebecca J.; Eisen, Lars; Castro, Martin B.; Lane, Robert S.
Environmentally related variability in risk of exposure to Lyme disease spirochetes in northern … Journal Article
In: Environmental Entomology, vol. 32, no. 5, pp. 1010-1018, 2003.
Abstract | Links | BibTeX | Tags: Borrelia burgdorferi, habitat, human risk, Ixodes pacificus, Lyme disease
@article{Eisen2003,
title = {Environmentally related variability in risk of exposure to Lyme disease spirochetes in northern …},
author = {Rebecca J. Eisen and Lars Eisen and Martin B. Castro and Robert S. Lane},
url = {https://angelo.berkeley.edu/wp-content/uploads/sites/59/Environmentally-Related-Variability-in-Risk-of-Exposure-to-Lyme-Disease-Spirochetes-in-Northern-California-Effect-of-Climatic-Conditions-and-Habitat-Type_Eisen_2002.pdf},
doi = {http://dx.doi.org/10.1603/0046-225X-32.5.1010},
year = {2003},
date = {2003-05-06},
journal = {Environmental Entomology},
volume = {32},
number = {5},
pages = {1010-1018},
abstract = {Risk of exposure to Borrelia burgdorferi sensu lato (s.l.) spirochetes, which include the causative agents of Lyme disease, is, in part, determined by the density of questing infected vector ticks. We sought to clarify the temporal patterns of nymphal activity, and the extent of variation in peak and cumulative densities of B. burgdorferi s.l.-infected Ixodes pacificus Cooley & Kohls nymphs, at 12 sites within the ecologically diverse Mendocino County in northwestern California. Also, we assessed the impact of various environmental characteristics (e.g., climatologic variables, habitat type, deer usage) on the aforementioned tick-related traits. The average durations of total and peak (nymphal density > 75% of absolute peak) questing activity were 31% and 82% longer, respectively, in areas with conifers present than in oak woodlands, which represented the warmest and driest habitat type examined. Peak and cumulative densities of infected nymphs varied > 400-fold between sites. Both traits were positively associated with the presence of Quercus spp. oaks or deer, and lower in redwood/tanoak versus oak and oak/Douglas fir habitats. However, a prolonged duration of nymphal activity in redwood habitats, relative to oak woodlands, resulted in a shift from peak nymphal densities occurring in oak woodlands in spring to redwood/tanoak habitats in summer. In conclusion, our data clearly show significant variability in seasonal as well as spatial risk of exposure to Lyme disease spirochetes within a small but ecologically, diverse geographic area. Hence, temporally dynamic and spatially explicit models are needed to assess the risk of exposure to tick-borne pathogens at spatial scales encompassing diverse climatologic or ecological conditions.},
keywords = {Borrelia burgdorferi, habitat, human risk, Ixodes pacificus, Lyme disease},
pubstate = {published},
tppubtype = {article}
}
Risk of exposure to Borrelia burgdorferi sensu lato (s.l.) spirochetes, which include the causative agents of Lyme disease, is, in part, determined by the density of questing infected vector ticks. We sought to clarify the temporal patterns of nymphal activity, and the extent of variation in peak and cumulative densities of B. burgdorferi s.l.-infected Ixodes pacificus Cooley & Kohls nymphs, at 12 sites within the ecologically diverse Mendocino County in northwestern California. Also, we assessed the impact of various environmental characteristics (e.g., climatologic variables, habitat type, deer usage) on the aforementioned tick-related traits. The average durations of total and peak (nymphal density > 75% of absolute peak) questing activity were 31% and 82% longer, respectively, in areas with conifers present than in oak woodlands, which represented the warmest and driest habitat type examined. Peak and cumulative densities of infected nymphs varied > 400-fold between sites. Both traits were positively associated with the presence of Quercus spp. oaks or deer, and lower in redwood/tanoak versus oak and oak/Douglas fir habitats. However, a prolonged duration of nymphal activity in redwood habitats, relative to oak woodlands, resulted in a shift from peak nymphal densities occurring in oak woodlands in spring to redwood/tanoak habitats in summer. In conclusion, our data clearly show significant variability in seasonal as well as spatial risk of exposure to Lyme disease spirochetes within a small but ecologically, diverse geographic area. Hence, temporally dynamic and spatially explicit models are needed to assess the risk of exposure to tick-borne pathogens at spatial scales encompassing diverse climatologic or ecological conditions.