Hemorrhagic Disease in Montana’s Wild Ruminants

Epizootic hemorrhagic disease and bluetongue virus have been documented in Montana for decades.  Montana has experienced localized and variable population declines in wild cervids when these outbreaks occur.  Transmission is seasonal in North America, with infection occurring in the late summer and fall.  In northern states, transmission ends once adult vectors cease activity with the onset of winter.  Montana is in an epidemic zone where outbreaks appear periodically and mortality events can be significant.  Montana Fish, Wildlife and Parks wildlife health lab has tested samples from suspected outbreak events, research captures and opportunistically for detection of EHD and BTV.  Environmental factors and virus-vector-host interactions are knowledge gaps that need to be addressed to improve our understanding of these orbivirus dynamics.  Enhanced reporting, surveillance, and research efforts are potential tools that may improve our understanding of the role these viruses play in wild ruminant populations across the state

Wolf Disease Summary 2004-2014

Canine distemper virus (CDV), canine parvovirus (CPV), canine adenovirus (CAV), canine herpesvirus (CHV), neosporosis, leptospirosis, Brucella abortus and B. canis are diseases that have wolf health or wildlife management implications. Blood serum samples from wolves captured and collared for management purposes between 2004-2014 were screened for these pathogens. Serologic tests for leptospirosis, B. abortus, and B. canis were completed by the Montana Department of Livestock Diagnostic Laboratory with the remaining tests performed by Cornell University Animal Health Diagnostic Center (Cornell University, AHDC).  Samples were assigned as being collected in the Northwest or Southwest region of the state based on capture location and the region designation provided by Montana Fish, Wildlife and Parks wolf specialists. We evaluated and compared pathogen presence and prevalence within Northwest and Southwest Montana.  Each disease and its potential implications in the Northwest and Southwest region is discussed

2015 Wildlife Disease Retrospective

Montana Fish, Wildlife and Parks is developing a Wildlife Health Program.  One of the functions of the program is to integrate disease surveillance, population health monitoring, and wildlife health diagnostic services to provide information to the public and wildlife professionals on the dynamics, risk, and impacts of disease in Montana’s wildlife.   The knowledge gained from this program is aimed at improving conservation efforts and the safety of both humans and domestic animals.  The Wildlife Health Laboratory is a statewide lab that receives hundreds to thousands of biological samples each year for disease surveillance projects, epidemiologic and morbidity investigations, and forensics.  An overview of notable zoonotic and non-zoonotic diseases detected from 2015 laboratory submissions will be discussed, providing relevance, repercussions and general background or recent history of the diseases in Montana

Hemorrhagic Disease in Montana

Hemorrhagic Disease (HD) is caused by two groups of orbiviruses, bluetongue (BT) and epizootic hemorrhagic disease (EHD).   Both BT and EHD are capable of causing large scale mortalities in white-tailed deer.   Although both are capable of causing disease in other species, BT typically causes clinical symptoms and mortality in a larger range of species, including pronghorn and domestic sheep.   Three subtypes of EHD and five subtypes of BT are known to exist in North America.  Only EHD subtype 2 and BT subtype 17 have been identified in Montana.  Both BT and EHD are transmitted by a biting midge and the onset of disease typically occurring in late summer/early fall with mortality cases decreasing rapidly after the first killing frost.  HD was first documented in Montana in 1961.  Montana Fish, Wildlife and Parks has participated in a national survey documenting HD occurrence since that time.  Outbreaks within Montana appear to be becoming more frequent and the area affected has increased.  Until 2013 HD had been limited to the east side of the Rocky Mountain front.  However, in 2013 several counties in western Montana experience their first recorded EHD die-off in white-tailed deer.  The history and potential future ramifications of HD outbreaks in MT are discussed

Assessing Brucellosis Seroprevalence and Transmission Risk in a Free-Ranging Elk Population: The Targetted Brucellosis Surveillance Project in Montana

Brucellosis is a bacterial disease that affects elk, bison and domestic cattle.  Recently the seroprevalence of brucellosis in free-ranging elk populations of Montana has increased and its’ range has expanded, resulting in increased pressure on Montana Fish, Wildlife and Parks (MFWP) to manage the disease in elk.  In 2010 MFWP and the Montana Department of Livestock initiated a targeted surveillance program to delineate the current geographic distribution of brucellosis, document spatio-temporal habitat selection and movement patterns, and to quantify potential transmission risk from elk to cattle.  Since 2010, we have targeted 11 different winter ranges from 9 hunt districts, both within and outside of the Designated Surveillance Area used to manage cattle.  During each capture operation we tested approximately 100 adult female elk for exposure to brucellosis.  We deployed GPS radiocollars on a subsample of adult female elk on each winter range.  An epidemiological summary of the first five years, including seroprevalence, movement and implications for transmission vectors will be presented. Current brucellosis exposure in domestic herds, future surveillance areas, evaluation of various management actions on transmission risk, and the creation of a spatio-temporal risk model are discussed

Elk Movements and Brucellosis Transmission Risk in Southwest Montana

The presence of Brucella abortus within free-ranging elk populations is an important conservation and management issue because of the risk of brucellosis transmission to livestock. Understanding elk distributions is necessary to forecast elk and livestock spatial overlap and the potential for brucellosis transmission. As part of a 5-yr brucellosis surveillance project, 30 adult female elk were captured and fitted with GPS collars in each of the winters of 2010, 2011 and 2012 in three southwest Montana study areas. We used elk location information to assess elk movements, and spatial overlap with livestock and adjacent elk herds. The elk movement results were further augmented with data from Wyoming and Idaho elk herds. The elk movement data shows interchange of females between elk herds during the transmission risk period. Resource selection models predicting elk distribution and spatial overlap with livestock during the transmission risk period were developed and extrapolated across the designated brucellosis surveillance area of Montana. We used the elk location data collected in this study to validate and refine models predicting elk distributions and spatial overlap with livestock during the risk period. Predictive models may be used as a tool for focusing management actions aimed at minimizing elk and livestock spatial overlap during the transmission risk period

Spatial and Temporal Patterns of Trichinella in Montana’s Black Bears, 2004-2014

Trichinella nematodes are a globally distributed, zoonotic parasite transmitted through the consumption of infected animal tissue. Humans are at risk of contracting Trichinella by consuming undercooked bear or mountain lion meat, and thus historically, Montana Fish, Wildlife, and Parks subsidized Trichinella-testing of hunter-harvested black bears (Ursus americanus) and mountain lions (Puma concolor). Here, we summarize 11 years of data (2004-2014) on the spatial and temporal distribution of Trichinella in Montana’s black bears. Risk of infection was spatially variable, highest in northwest Regions 1 and 4, and was positively associated with black bear and grizzly bear (Ursus arctos horrobilis) densities. Prevalence has been significantly declining across the state over time from a state-wide prevalence of 0.05 in 2004 to 0.02 in 2014. Potential causes and consequences are discussed.  Montana Fish, Wildlife, and Parks stopped subsidizing Trichinella testing in 2015; hunters are asked to thoroughly cook their meat to an internal temperature of 165° F, which inactivates Trichinella species and most other parasites

Icarus Rewaxed: A high speed, low-cost general aviation aircraft for Aeroworld

Icarus Rewaxed is a single engine, six passenger, general aviation airplane. With a cruise velocity of 72 ft/s, the Icarus can compete with the performance of any other airplane in its class with an eye on economics and safety. It has a very competitive initial price ($3498.00) and cost per flight ($6.36-8.40). Icarus can serve all airports in Aeroworld with a takeoff distance of 25.4 feet and maximum range of 38,000 feet. It is capable of taking off from an unprepared field with a grass depth of 3 inches. Icarus Rewaxed fills the market need for a high-speed, low cost aircraft. It provides customers with a general aviation craft that can compete in the existing performance market with the added security of an advanced structure. With the use of advanced materials, the maneuvering capability of the Icarus is increased, as it can withstand greater load factors than previous aircraft

Preliminary Findings of an Elk Brucellosis Surveillance and Epidemiology Project in Southwestern Montana

Brucellosis is a bacterial disease that causes abortions in cattle, bison (Bison bison) and elk (Cervus elaphus). Transmission of the disease from wildlife to cattle has serious financial implications to producers and the livestock industry in Montana. Brucellosis in elk populations of southwestern Montana results in reduced tolerance for elk on private property and can influence management of elk populations. In the winter of 2010/2011, Montana Fish, Wildlife and Parks initiated a five-year project with the goals of delineating the geographical distribution of brucellosis in elk populations, enhancing our understanding of how brucellosis functions in elk populations, and evaluating factors that may influence the spread and prevalence of brucellosis in elk. One-hundred adult female elk were captured in hunting districts (HD) 324 and 326 in the winter of 2010/2011 with eight testing positive on blood tests(seropositive) in the field for exposure to Brucella. Ninety-three adult female elk were captured in HD 325 in the winter of 2011/2012, five of which were seropositive. Elk testing positive in the field were fitted with a GPS collar and, if pregnant, implanted with a vaginal implant transmitter (VIT). Seropositive pregnant elk were tracked from the ground and air 2-3 times/week in order to locate birth or abortion sites. B. abortus was not cultured from VITs or samples collected at birth sites in the first year of the project. B. abortus was cultured from tissues or VITs associated with two aborted calves in 2012. The known distribution of brucellosis in elk has expanded based on information obtained in this study

Modeling Management Strategies for the Control of Bighorn Sheep Respiratory Disease

Infectious pneumonia has plagued bighorn sheep populations and stymied recovery efforts across the western United States for decades.  Here we present a simple, non-spatial, stochastic, discrete-time model that captures basic bighorn sheep demographics and in which we simulate the dynamics of Mycoplasma ovipneumoniae, the suspected primary causative agent in bighorn sheep respiratory disease. We then use the model to explore the impacts of management approaches, including augmentation, depopulation and reintroduction, density reduction, and test-and-cull, aimed at reducing or eliminating the pathogen, its transmission, or associated infection costs. Results suggest that test-and-cull (testing 95% of a herd and removing PCR-positive individuals) and depopulation and reintroduction (assuming ability to only depopulate 95% of the herd) offer the best probability of eliminating the pathogen, although neither are expected to be 100% successful. Augmentation (adding 30 adult ewes) does not increase the probability of pathogen extinction, and in some cases may prolong pathogen persistence and diminish herd recovery.  Density reduction (randomly removing 25-50% of the herd) only modestly increases the probability of stochastic pathogen extinction and herd recovery.  Stochastic pathogen extinction and herd recovery is predicted to occur on occasion without any management intervention. Ultimately, decisions to manage respiratory disease in wild sheep must weigh the predicted success of the management tool against financial, logistical, ethical, and value-based considerations. Here, we aim to supply mechanistic-based predictions of the relative efficacy of currently employed or proposed tools, as well as characterize the sensitivity of these predictions to our assumptions about how the disease process works