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Behavioral Ecology and Sociobiology

, Volume 67, Issue 12, pp 1951–1959 | Cite as

Network structure and prevalence of Cryptosporidium in Belding’s ground squirrels

  • Kimberly L. VanderWaal
  • Edward R. Atwill
  • Stacie Hooper
  • Kelly Buckle
  • Brenda McCowanEmail author
Original Paper

Abstract

Although pathogen transmission dynamics are profoundly affected by population social and spatial structure, few studies have empirically demonstrated the population-level implications of such structure in wildlife. In particular, epidemiological models predict that the extent to which contact patterns are clustered decreases a pathogen’s ability to spread throughout an entire population, but this effect has yet to be demonstrated in a natural population. Here, we use network analysis to examine patterns of transmission of an environmentally transmitted parasite, Cryptosporidium spp., in Belding’s ground squirrels (Spermophilus beldingi). We found that the prevalence of Cryptosporidium was negatively correlated with transitivity, a measure of network clustering, and positively correlated with the percentage of juvenile males. Additionally, network transitivity decreased when there were higher percentages of juvenile males; the exploratory behavior demonstrated by juvenile males may have altered the structure of the network by reducing clustering, and low clustering was associated with high prevalence. We suggest that juvenile males are critical in mediating the ability of Cryptosporidium to spread through colonies, and thus may function as “super-spreaders.” Our results demonstrate the utility of a network approach in quantifying mechanistically how differences in contact patterns may lead to system-level differences in infection patterns.

Keywords

Social networks Cryptosporidium Ground squirrels Pathogen transmission Infection patterns Clustering Wildlife disease 

Notes

Acknowledgments

We thank Jennifer Dike and Katryna Fleer for their assistance in data collection and Allison Heagerty for her comments and contributions to data analysis. We also thank two anonymous reviewers for their constructive comments on an earlier version of this manuscript. This work was conducted under the auspices of the Bernice Barbour Communicable Disease Laboratory, with financial support from the Bernice Barbour Foundation, Hackensack, N.J., as a grant to the Center of Equine Health, University of California, Davis.

Ethical standards

The experiments described herein comply with the current laws of the USA.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Kimberly L. VanderWaal
    • 1
    • 2
  • Edward R. Atwill
    • 3
    • 4
  • Stacie Hooper
    • 5
  • Kelly Buckle
    • 6
  • Brenda McCowan
    • 2
    • 3
    Email author
  1. 1.Animal Behavior Graduate GroupUniversity of California—DavisDavisUSA
  2. 2.International Institute for Human–Animal NetworksUniversity of California—DavisDavisUSA
  3. 3.Department of Population Health and Reproduction, School of Veterinary MedicineUniversity of California—DavisDavisUSA
  4. 4.Western Institute for Food Safety and SecurityUniversity of California—DavisDavisUSA
  5. 5.Department of Ecology and EvolutionUniversity of California—DavisDavisUSA
  6. 6.School of Veterinary ScienceThe University of QueenslandGattonAustralia

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