<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="6.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Jolles, Anna E</style></author><author><style face="normal" font="default" size="100%">Etienne, Rampal S</style></author><author><style face="normal" font="default" size="100%">Olff, Han</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Independent and competing disease risks: implications for host populations in variable environments.</style></title><secondary-title><style face="normal" font="default" size="100%">The American naturalist</style></secondary-title><alt-title><style face="normal" font="default" size="100%">Am. Nat.</style></alt-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Animals</style></keyword><keyword><style  face="normal" font="default" size="100%">Buffaloes</style></keyword><keyword><style  face="normal" font="default" size="100%">Climate</style></keyword><keyword><style  face="normal" font="default" size="100%">Environment</style></keyword><keyword><style  face="normal" font="default" size="100%">Fertility</style></keyword><keyword><style  face="normal" font="default" size="100%">Models, Biological</style></keyword><keyword><style  face="normal" font="default" size="100%">Population Density</style></keyword><keyword><style  face="normal" font="default" size="100%">Population Dynamics</style></keyword><keyword><style  face="normal" font="default" size="100%">South Africa</style></keyword><keyword><style  face="normal" font="default" size="100%">Survival Analysis</style></keyword><keyword><style  face="normal" font="default" size="100%">Tuberculosis</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2006</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2006 May</style></date></pub-dates></dates><volume><style face="normal" font="default" size="100%">167</style></volume><pages><style face="normal" font="default" size="100%">745-57</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Disease models usually assume disease to act independently of other mortality- and morbidity-causing factors. Alternatively, disease may function as a competing risk factor, for example, killing already moribund hosts. Using tuberculosis (TB) in African buffalo as a model system, we explore consequences of competing or independent disease effects for host population dynamics. We include scenarios with density-dependent and density-independent effects of environmental variation, exemplified by variable food availability (driven by rainfall) and catastrophic droughts, respectively. Independent disease effects reduce population size linearly with prevalence, irrespective of the nature of environmental variation. Competing disease risks alter population size only if density-independent variation is present; then, disease reduces population size nonlinearly. Field data indicate that the net effect of TB on buffalo likely falls between the extremes of total independence and competition with other risk factors: TB increases mortality and decreases fecundity in some prime-aged buffalo, suggesting independent disease risks in these individuals, while similar disease effects in senescent buffalo may act as competing risks. Moreover, increased survival and fecundity of TB-negative buffalo may compensate for some disease-related losses. Model assumptions on independent or competing disease risks and environmental variability should be considered explicitly when assessing disease effects on wildlife populations.</style></abstract><issue><style face="normal" font="default" size="100%">5</style></issue><custom1><style face="normal" font="default" size="100%">http://www.ncbi.nlm.nih.gov/pubmed/16671018?dopt=Abstract</style></custom1></record></records></xml>