Life Sciences Commons^™

Hidden Cost Of Disease In A Free-Ranging Ungulate: Brucellosis Reduces Mid-Winter Pregnancy In Elk, Gavin C. Cotterill, Paul C. Cross, Arthur D. Middleton, Jared D. Rogerson, Brandon M. Scurlock, Johan T. Du Toit

Wildland Resources Faculty Publications

Demonstrating disease impacts on the vital rates of free‐ranging mammalian hosts typically requires intensive, long‐term study. Evidence for chronic pathogens affecting reproduction but not survival is rare, but has the potential for wide‐ranging effects. Accurately quantifying disease‐associated reductions in fecundity is important for advancing theory, generating accurate predictive models, and achieving effective management. We investigated the impacts of brucellosis (Brucella abortus) on elk (Cervus canadensis) productivity using serological data from over 6,000 captures since 1990 in the Greater Yellowstone Ecosystem, USA. Over 1,000 of these records included known age and pregnancy status. Using Bayesian multilevel models, …

Interactions And Pathogen Transmission Between Carnivores In Madagascar, Fidisoa Rasambainarivo

Dissertations

Introduced carnivores exert considerable pressure on native predators through predation, competition and disease transmission. Improved understanding of determinant factors of interactions and pathogen transmission between introduced and endemic wildlife may help to predict disease emergence, avoid pathogen spillover and help control outbreaks. Using non-invasive camera traps, I identified areas where transmission of pathogens might happen through records of shared space-use within a protected area in Eastern Madagascar. I showed that indirect interactions between animals were more likely to occur near the research station which may constitute a disease transmission hotspot for carnivores in the landscape. Secondly, I investigated the associations …

Winter Feeding Of Elk In The Greater Yellowstone Ecosystem And Its Effects On Disease Dynamics, Gavin C. Cotterill, Paul C. Cross, Erik K. Cole, Rebecca K. Fuda, Jared D. Rogerson, Brandon M. Scurlock, Johan T. Du Toit

Wildland Resources Faculty Publications

Providing food to wildlife during periods when natural food is limited results in aggregations that may facilitate disease transmission. This is exemplified in western Wyoming where institutional feeding over the past century has aimed to mitigate wildlife–livestock conflict and minimize winter mortality of elk (Cervus canadensis). Here we review research across 23 winter feedgrounds where the most studied disease is brucellosis, caused by the bacterium Brucella abortus. Traditional veterinary practices (vaccination, test-and-slaughter) have thus far been unable to control this disease in elk, which can spill over to cattle. Current disease-reduction efforts are being guided by ecological …

Experimental Evidence Of A Pathogen Invasion Threshold, Tad Dallas, Martin Krkošek, John M. Drake

Faculty Publications

Host density thresholds to pathogen invasion separate regions of parameter space corresponding to endemic and disease-free states. The host density threshold is a central concept in theoretical epidemiology and a common target of human and wildlife disease control programmes, but there is mixed evidence supporting the existence of thresholds, especially in wildlife populations or for pathogens with complex transmission modes (e.g. environmental transmission). Here, we demonstrate the existence of a host density threshold for an environmentally transmitted pathogen by combining an epidemiological model with a microcosm experiment. Experimental epidemics consisted of replicate populations of naive crustacean zooplankton (Daphnia dentifera …

Rna Virus Ecology In Bumble Bees (Bombus Spp.) And Evidence For Disease Spillover, Samantha Ann Alger

Graduate College Dissertations and Theses

The inadvertent spread of exotic pests and pathogens has resulted in devastating losses for bees. The vast majority of bee disease research has focused on a single species of managed bee, the European honey bee (Apis mellifera). More recently, pathogen spillover from managed bees is implicated in the decline of several bumble bee species (Bombus spp.) demonstrating a need to better understand the mechanisms driving disease prevalence in bees, transmission routes, and spillover events.

RNA viruses, once considered specific to honey bees, are suspected of spilling over from managed honey bees into wild bumble bee populations. To test this, I …