Interacting effects of wildlife loss and climate on ticks and tick-borne disease

Georgia Titcomb, Brian F. Allan, Tyler Ainsworth, Lauren Henson, Tyler Hedlund, Robert Mitchell Pringle, Todd M. Palmer, Laban Njoroge, Michael G. Campana, Robert C. Fleischer, John Naisikie Mantas, Hillary S. Young

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

Both large-wildlife loss and climatic changes can independently influence the prevalence and distribution of zoonotic disease. Given growing evidence that wildlife loss often has stronger community-level effects in low-productivity areas, we hypothesized that these perturbations would have interactive effects on disease risk. We experimentally tested this hypothesis by measuring tick abundance and the prevalence of tick-borne pathogens (Coxiella burnetii and Rickettsia spp.) within long-term, size-selective, large-herbivore exclosures replicated across a precipitation gradient in East Africa. Totalwildlife exclusion increased total tick abundance by 130% (mesic sites) to 225% (dry, lowproductivity sites), demonstrating a significant interaction of defaunation and aridity on tick abundance. When differing degrees of exclusion were tested for a subset of months, total tick abundance increased from 170% (only mega-herbivores excluded) to 360% (all largewildlife excluded).Wildlife exclusion differentially affected the abundance of the three dominant tick species, and this effect varied strongly over time, likely due to differences among species in their host associations, seasonality, and other ecological characteristics. Pathogen prevalence did not differ acrosswildlife exclusion treatments, rainfall levels, or tick species, suggesting that exposure riskwill respond to defaunation and climate change in proportion to total tick abundance. These findings demonstrate interacting effects of defaunation and aridity that increase disease risk, and they highlight the need to incorporate ecological context when predicting effects of wildlife loss on zoonotic disease dynamics.

Original languageEnglish (US)
Article number20170475
JournalProceedings of the Royal Society B: Biological Sciences
Volume284
Issue number1862
DOIs
StatePublished - Sep 13 2017

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Environmental Science(all)
  • Agricultural and Biological Sciences(all)

Keywords

  • Climate
  • Coxiella burnetii
  • Defaunation
  • Exclosure
  • Tick-borne disease
  • Ticks

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    Titcomb, G., Allan, B. F., Ainsworth, T., Henson, L., Hedlund, T., Pringle, R. M., Palmer, T. M., Njoroge, L., Campana, M. G., Fleischer, R. C., Mantas, J. N., & Young, H. S. (2017). Interacting effects of wildlife loss and climate on ticks and tick-borne disease. Proceedings of the Royal Society B: Biological Sciences, 284(1862), [20170475]. https://doi.org/10.1098/rspb.2017.0475