The effects of demographic, social, and environmental characteristics on pathogen prevalence in wild felids across a gradient of urbanization.

Jesse S Lewis,Sue Vandewoude,Kenneth A Logan,Sarah N Bevins,Scott Carver,Mat W Alldredge,Kevin R Crooks,Michael Lappin

doi:10.1371/journal.pone.0187035

Abstract

Transmission of pathogens among animals is influenced by demographic, social, and environmental factors. Anthropogenic alteration of landscapes can impact patterns of disease dynamics in wildlife populations, increasing the potential for spillover and spread of emerging infectious diseases in wildlife, human, and domestic animal populations. We evaluated the effects of multiple ecological mechanisms on patterns of pathogen exposure in animal populations. Specifically, we evaluated how ecological factors affected the prevalence of Toxoplasma gondii (Toxoplasma), Bartonella spp. (Bartonella), feline immunodeficiency virus (FIV), and feline calicivirus (FCV) in bobcat and puma populations across wildland-urban interface (WUI), low-density exurban development, and wildland habitat on the Western Slope (WS) and Front Range (FR) of Colorado during 2009–2011. Samples were collected from 37 bobcats and 29 pumas on the WS and FR. As predicted, age appeared to be positively related to the exposure to pathogens that are both environmentally transmitted (Toxoplasma) and directly transmitted between animals (FIV). In addition, WS bobcats appeared more likely to be exposed to Toxoplasma with increasing intraspecific space-use overlap. However, counter to our predictions, exposure to directly-transmitted pathogens (FCV and FIV) was more likely with decreasing space-use overlap (FCV: WS bobcats) and potential intraspecific contacts (FIV: FR pumas). Environmental factors, including urbanization and landscape covariates, were generally unsupported in our models. This study is an approximation of how pathogens can be evaluated in relation to demographic, social, and environmental factors to understand pathogen exposure in wild animal populations.

Highlights

Infectious diseases play important roles in wildlife conservation and can threaten species and populations across local to global scales [1,2,3,4,5,6]
As predicted for some pathogens, individuals were more likely to be exposed with increasing age; this covariate occurred in the top-ranked models for feline immunodeficiency virus (FIV) in Western Slope (WS) bobcats (S3 Table) and Toxoplasma in Front Range (FR) bobcats (S10 Table) and FR pumas (S13 Table)
Counter to predictions, space use extent was negatively related to feline calicivirus (FCV) for WS bobcats (β = -1.72, se = 1.24; Table 4); this covariate occurred in top-ranked models (S5 Table) and had a variable importance values (VIV) = 0.42 (Table 3)

Summary

Introduction

Infectious diseases play important roles in wildlife conservation and can threaten species and populations across local to global scales [1,2,3,4,5,6]. To conserve animal populations and reduce the risk of infectious and zoonotic pathogen spread in wildlife and humans, it is critical to understand the mechanisms that affect patterns of disease in wildlife populations across different forms of urbanization, as it relates to modes of pathogen transmission [18,19,20,21]. Males tend to have larger extents of space use [29] and greater potential for contacts among animals [30]. Because larger extents of space use allow animals a greater opportunity to interact with the landscape, animals can potentially experience increased exposure to pathogens in the environment. Transmission of parasites within populations can decrease with increasing host density, associated with less mixing among individuals within a population and more localized disease transmission [32]

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Conclusion