Tyler Creech

Research interests:

Current Research Projects:
Thesis: Brucella transmission and contact rates among elk in the Greater Yellowstone Ecosystem

A critical parameter in the study and management of wildlife diseases is the rate of transmission from infected individuals to susceptible individuals. The transmission rate for an infectious disease depends largely on the rate and type of contact between individuals, but quantifying contact typically requires a major investment of time and resources. For this reason, population density is often used as a proxy for contact, based on the untested assumption that contact rate and density are directly and positively correlated.

An emerging technique for directly estimating contact rates is the use of proximity collars – traditional VHF or GPS collars coupled with dataloggers that record the timing and identity of contacts with other dataloggers. Proximity collars facilitate the collection of large amounts of contact data at relatively fine spatial and temporal scales, and thus have great potential as a research tool for wildlife ecologists and epidemiologists.

I am conducting a study of proximity-collared elk in the Greater Yellowstone Ecosystem to evaluate the effects of alternative management strategies on the transmission of brucellosis in elk. Brucellosis is a bacterial disease that causes abortions in elk and is transmitted by exposure to infected reproductive tissues including aborted fetuses, fetal fluids, and placentas. The practice of supplemental feeding of elk during winter has been implicated in the spread and persistence of brucellosis within elk populations because feedgrounds support unnaturally high elk densities that promote disease transmission.

An alternative to traditional supplemental feeding that has been proposed for reducing brucellosis seroprevalence in elk is “low-density” feeding, in which feed is dispersed over a large area within the feedground rather than along a feedline, presumably reducing contacts and disease transmission. If low-density feeding is truly effective at reducing disease transmission, then significantly lower contact rates should be observed on feedgrounds implementing this strategy. By outfitting elk from one traditional feedground and one low-density feedground with proximity collars and systematically placing aborted elk fetuses equipped with proximity dataloggers within these feedgrounds, I will be able to estimate elk-elk and elk-fetus contact rates for each feedground and determine the efficacy of low-density feeding. From a theoretical perspective, I will also be using data from the proximity-collared elk to explore the relationship between contact rate and elk density and to find methods for scaling up from individual- to population-level estimates of contact.