Maintenance of brucellosis in Yellowstone bison: linking seasonal food resources, host–pathogen interaction, and life‐history trade‐offs

Ecology and Evolution

John J. Treanor³  Chris Geremia³  Michael A. Ballou¹  Duane H. Keisler²  Patrick J. White³  John J. Cox⁴ 

[1] Department of Animal and Food Sciences, Texas Tech University, Lubbock, Texas;Division of Animal Sciences, University of Missouri, Columbia, Missouri;National Park Service, Yellowstone National Park, Mammoth Hot Springs, Wyoming;Department of Forestry, University of Kentucky, Lexington, Kentucky

关键词: Age;    Brucella abortus;    condition;    diet;    energy;    immune;    interferon‐γ;    leptin;    nutrition;    protein;   

DOI  :  10.1002/ece3.1633

来源: Wiley

【 摘 要 】

Abstract

The seasonal availability of food resources is an important factor shaping the life-history strategies of organisms. During times of nutritional restriction, physiological trade-offs can induce periods of immune suppression, thereby increasing susceptibility to infectious disease. Our goal was to provide a conceptual framework describing how the endemic level bovine brucellosis (Brucella abortus) may be maintained in Yellowstone bison based on the seasonality of food resources and the life-history strategies of the host and pathogen. Our analysis was based on active B. abortus infection (measured via bacterial culture), nutritional indicators (measured as metabolites and hormones in plasma), and carcass measurements of 402 slaughtered bison. Data from Yellowstone bison were used to investigate (1) whether seasonal changes in diet quality affect nutritional condition and coincide with the reproductive needs of female bison; (2) whether active B. abortus infection and infection intensities vary with host nutrition and nutritional condition; and (3) the evidence for seasonal changes in immune responses, which may offer protection against B. abortus, in relation to nutritional condition. Female bison experienced a decline in nutritional condition during winter as reproductive demands of late gestation increased while forage quality and availability declined. Active B. abortus infection was negatively associated with bison age and nutritional condition, with the intensity of infection negatively associated with indicators of nutrition (e.g., dietary protein and energy) and body weight. Data suggest that protective cell-mediated immune responses may be reduced during the B. abortus transmission period, which coincides with nutritional insufficiencies and elevated reproductive demands during spring. Our results illustrate how seasonal food restriction can drive physiological trade-offs that suppress immune function and create infection and transmission opportunities for pathogens.

【 授权许可】

CC BY   
© 2015 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.