10.5061/DRYAD.C15PH
Cross, Paul C.
United States Geological Survey
Maichak, Eric J.
Wyoming Game and Fish Department; Pinedale WY 82941 USA
Rogerson, Jared D.
Montana State University
Irvine, Kathryn M.
United States Geological Survey
Jones, Jennifer D.
Montana State University
Heisey, Dennis M.
National Wildlife Health Center
Edwards, William H.
Wyoming Game and Fish Department; Laramie WY 82070 USA
Scurlock, Brandon M.
Wyoming Game and Fish Department; Pinedale WY 82941 USA
Data from: Estimating the phenology of elk brucellosis transmission with
hierarchical models of cause-specific and baseline hazards
Dryad
dataset
2016
vaginal implant transmitter
wildlife disease
Greater Yellowstone Ecosystem
Cervus elaphus
time to event
Brucella abortus
2016-04-14T00:00:00Z
2016-04-14T00:00:00Z
en
https://doi.org/10.1002/jwmg.883
54077 bytes
1
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Understanding the seasonal timing of disease transmission can lead to more
effective control strategies, but the seasonality of transmission is often
unknown for pathogens transmitted directly. We inserted vaginal implant
transmitters (VITs) in 575 elk (Cervus elaphus canadensis) from 2006 to
2014 to assess when reproductive failures (i.e., abortions or still
births) occur, which is the primary transmission route of Brucella
abortus, the causative agent of brucellosis in the Greater Yellowstone
Ecosystem. Using a survival analysis framework, we developed a Bayesian
hierarchical model that simultaneously estimated the total baseline hazard
of a reproductive event as well as its 2 mutually exclusive parts
(abortions or live births). Approximately, 16% (95% CI = 0.10, 0.23) of
the pregnant seropositive elk had reproductive failures, whereas 2% (95%
CI = 0.01, 0.04) of the seronegative elk had probable abortions.
Reproductive failures could have occurred as early as 13 February and as
late as 10 July, peaking from March through May. Model results suggest
that less than 5% of likely abortions occurred after 6 June each year and
abortions were approximately 5 times more likely in March, April, or May
compared to February or June. In western Wyoming, supplemental feeding of
elk begins in December and ends during the peak of elk abortions and
brucellosis transmission (i.e., Mar and Apr). Years with more snow may
enhance elk-to-elk transmission on supplemental feeding areas because elk
are artificially aggregated for the majority of the transmission season.
Elk-to-cattle transmission will depend on the transmission period relative
to the end of the supplemental feeding season, elk seroprevalence,
population size, and the amount of commingling. Our statistical approach
allowed us to estimate the probability density function of different event
types over time, which may be applicable to other cause-specific survival
analyses. It is often challenging to assess the cause of death, or in this
case whether the reproductive event was an abortion or live birth.
Accounting for uncertainty in the event type is an important future
addition to our methodological approach.
Timing of elk births and abortionsData_dryad.xlsx
Wyoming
Yellowstone