Avian influenza virus prevalence in migratory waterfowl in the United States, 2007-2009.

We analyzed 155,535 samples collected for surveillance of avian influenza viruses (AIVs), in the United States from 2007 to 2009, from migratory waterfowl (ducks, geese, and swans). The goal was to elucidate patterns of prevalence by flyway and functional groups to determine targets for future surveillance. Apparent prevalence of AIV was highest in the Pacific Flyway in 2007-2008 (14.2% and 14.1%, respectively), in the Mississippi Flyway in 2009 (16.8%), and lowest each year in the Atlantic Flyway (range, 7.3%-8.9%). Dabbling ducks had higher apparent prevalence of AIV (12.8%-18.8%) than diving ducks (3.9%-6.0%) or geese and swans (3.6%-3.9%). We observed highest apparent prevalence in hatch-year waterfowl (15.6%-18.9%). We further analyzed 117,738 of the 155,535 samples to test the hypothesis mallard (Anasplatyrhynchos) had highest prevalence of AIV. We compared apparent prevalence and odds ratios for seven species of ducks and one species of goose commonly collected across the United States. Mallards had highest apparent prevalence (15%-26%) in half of comparisons made, whereas American green- winged teal (Anas creeca, 12%-13%), blue-winged teal (Anas discors, 13%-23%), northern pintail (Anas acuta, 16%-22%), or northern shoveler (Anas clypeata, 15%) had higher apparent prevalence in the remaining comparisons. The results of our research can be used to tailor future surveillance that targets flyways, functional groups, and species with the highest probability of detecting AIV.

Resource selection by elk in an agro-forested landscape of northwestern Nebraska.

In recent years, elk have begun recolonizing areas east of the Rocky Mountains that are largely agro-forested ecosystems composed of privately owned land where management of elk is an increasing concern due to crop and forage depredation and interspecific disease transmission. We used a Geographic Information System, elk use locations (n = 5013), random locations (n = 25,065), discrete-choice models, and information-theoretic methods to test hypotheses about elk resource selection in an agro-forested landscape located in the Pine Ridge region of northwestern Nebraska, USA. Our objectives were to determine landscape characteristics selected by female elk and identify publicly owned land within the Pine Ridge for potential redistribution of elk. We found distance to edge of cover influenced selection of resources by female elk most and that in areas with light hunting pressure, such as ours, this selection was not driven by an avoidance of roads. Female elk selected resources positioned near ponderosa pine cover types during all seasons, exhibited a slight avoidance of roads during spring and fall, selected areas with increased slope during winter and spring, and selected north- and east-facing aspects over flat areas and areas with south-facing slopes during winter months. We used our models to identified a potential elk redistribution area that had a higher proportion of landcover with characteristics selected by elk in our study area than the current herd areas and more landcover that was publicly owned. With appropriate management plans, we believe elk within the Potential Elk Redistribution Area would predominantly occupy publicly owned land, which would help minimize crop and forage damage on privately owned lands.

First record of Pseudorabies in feral swine in Nebraska.

In 2007, two new populations of feral swine were discovered in Nance and Valley counties, Nebraska, USA. Necropsies and serologic testing was done on two individuals from the Nance County herd. Results indicated that a lactating sow had positive antibodies for pseudorabies virus (PRV). Investigations conducted by Nebraska Game and Parks Commission Law Enforcement division confirmed that the infected individual was transported illegally to Nebraska, USA, from Texas, USA. All domestic swine herds located within an 8 km radius of the infected individual tested negative for antibodies to PRV. Our results provide a clear example of how diseases can spread because of anthropogenic activities and highlight the need for disease surveillance and monitoring in the import of invasive species.

Prevalence and serovars of Salmonella in the feces of free-ranging white-tailed deer (Odocoileus virginianus) in Nebraska.

To determine the prevalence and serovars of Salmonella in free-ranging deer, we cultured feces from white-tailed deer (Odocoileus virginianus) harvested by hunters during a regular firearm season in southeastern Nebraska (USA). We recovered Salmonella from 5 (1%; 95% confidence interval: 0.37-2.20%) of 500 samples and identified four different Salmonella enterica serovars [Litchfield (1), Dessau (1), Infantis (2), and Enteritidis (1)]. Although the prevalence of Salmonella in free-ranging deer appears to be low, the serovars recovered are known to be pathogenic to humans and animals.

Deer response to exclusion from stored cattle feed in Michigan, USA.

Disease and damage from white-tailed deer (Odocoileus virginianus) continually threaten the livelihood of agricultural producers and the economy in the United States, as well as challenge state and federal wildlife managers. Threats can be partially addressed by excluding free-ranging deer from livestock-related resources. Throughout the year, use of stored livestock feed by deer in northern Lower Michigan (MI), USA fluctuates, though their presence is relatively consistent. Since 2008, use of livestock areas and resources by deer has been reduced through intensive efforts by livestock producers in cooperation with state and federal agencies. These efforts focused on excluding deer from stored cattle feed in areas where deer were abundant. We monitored deer activity from Jan 2012 to June 2013 on 6 cattle farms in northern MI using GPS collars to evaluate behavioral effects of excluding deer from stored feed. We characterized areas deer occupied before and after installing 2361 m of fences and gates to exclude deer from stored cattle feed. Following fence installation, 9 deer previously accessing stored feed shifted to patterns of habitat use similar to 5 deer that did not use stored feed. However, continued attempts to regain access to stored feed were made at low frequencies, emphasizing the need to maintain the integrity of fences and keep gates closed for damage prevention and biosecurity.