Serological evidence of California group and Cache Valley virus infection in Minnesota white-tailed deer

Blood samples were obtained from 138 white-tailed deer (Odocoileus virginianus) harvested at three sites surrounding the greater Minneapolis-St. Paul, Minnesota, metropolitan area (USA) and tested for neutralizing antibody to Cache Valley virus and three California serogroup (Jamestown Canyon, La Crosse, trivittatus) viruses (Bunyaviridae). Deer at each site had neutralizing antibody to one or more California serogroup viruses and/or Cache Valley virus. The majority of adult deer (85%) had antibody to both a California serogroup virus and Cache Valley virus. Antibody prevalence varied significantly with age of the deer. Fawns had a significantly lower prevalence of antibody to either a California serogroup (17%) or Cache Valley virus (39%) than did older (greater than 1-yr-old) deer (89% for a California serogroup virus and 91% for Cache Valley virus). The geometric mean titers of antibody in fawns to California serogroup (1:6) and Cache Valley viruses (1:17) were also less than that seen in older animals (1:11 and 1:28 for California serogroup and Cache Valley viruses, respectively). Of 76 older deer with antibody to the California serogroup, 91% had antibody specific for Jamestown Canyon virus. Jamestown Canyon is the primary California serogroup virus circulating in the suburban/rural Minneapolis-St. Paul area. Transmission occurs in an enzootic pattern similar to that documented in Indiana and Michigan. Cache Valley virus also appears to be enzootically transmitted in this area. However, the impact on domestic or wild animal populations is unknown.     

Serologic evidence of arboviral infections in white-tailed deer from central Wisconsin

A survey conducted during 1979-1980 on white-tailed deer (Odocoileus virginianus) in central Wisconsin revealed serological evidence of infection by selected arboviruses. Among sera from 41 deer, antibody was detected for Jamestown Canyon virus (56%) and Bunyamwera group virus (80%), demonstrating their continuing endemic activity. Antibody for La Crosse virus, not found previously in sera from deer in central Wisconsin, also was detected (5%) in this study.     

Serum antibody prevalence for Herpesvirus sylvilagus, Bacillus piliformis and California serogroup arboviruses in cottontail rabbits from Pennsylvania

A serologic survey of 60 eastern cottontail rabbits (Sylvilagus floridanus) from three counties in Pennsylvania was conducted in March 1983. Serum antibody prevalences for Herpesvirus sylvilagus and La Crosse virus (California serogroup) were less than 4%. There was no evidence of previous exposure to either Jamestown Canyon or snowshoe hare viruses (California serogroup). Antibody to trivittatus virus (California serogroup) was found in 60% of the 20 cottontails from York County. No cottontails had antibodies to Bacillus piliformis, the etiologic agent of Tyzzer's disease.     

Prevalence of neutralizing antibody to Jamestown Canyon virus (California group) in populations of elk and moose in northern Michigan and Ontario, Canada

Blood samples were collected from free-ranging elk (Cervus elaphus) harvested in Michigan's northern Lower Peninsula, from moose (Alces alces) relocated from Ontario's Algonquin Provincial Park to Michigan's Upper Peninsula, and from moose from Michigan's Isle Royale National Park. Sera were tested by serum dilution neutralization tests in Vero cell culture for neutralizing antibody to California serogroup viruses, in particular Jamestown Canyon (JC), La Crosse/snowshoe hare (LAC/SSH), and trivittatus (TVT) viruses. Specific neutralizing antibody to JC virus was detected in 71% of 31 and 65% of 20 moose from Algonquin and Isle Royale, respectively. An additional six moose from Algonquin and five from Isle Royale showed evidence of multiple infection. One juvenile moose from Isle Royale had specific neutralizing antibody to TVT virus. Specific neutralizing antibody to JC virus was detected also in 54% of 50 elk from Michigan; 20 of the 50 elk showed evidence of multiple infection. While no single serum sample showed specific neutralizing antibody only to LAC/SSH virus, its presence in sera from some animals may have been masked by the high prevalence of antibody to JC virus.     

Movements of white-tailed deer in riparian habitat: Implications for infectious diseases

Movements of male white-tailed deer (Odocoileus virginianus) are of great concern with respect to spread of chronic wasting disease (CWD) across landscapes because most yearlings males disperse and adult males have higher prevalence of CWD than do females and younger deer. We radiocollared and monitored 85 male white-tailed deer in the middle Missouri River Valley of eastern Nebraska and western Iowa, USA from 2004 to 2008. Average size (±SE) of fixed-kernel annual home ranges (95%) and core areas (50%) for resident deer were 449 (±32) ha and 99 (±7) ha, respectively. Resident deer exhibited a high-degree of fidelity to their home ranges. Mean overlap between consecutive annual home ranges and core areas was 81% and 74%, respectively. Average dispersal distance was 17.7 ± 4.5 km (range = 3–121 km) for 22 radio-marked and 6 ear-tagged yearlings. Mean spring dispersal distance (25 km) was 150% greater than fall (10 km). Dispersal direction from Desoto National Wildlife Refuge (DNWR) was bimodal on a northwest to southeast axis that followed the Missouri River corridor. Of 22 yearlings that dispersed, 18 (82%) established adult home ranges within the river valley. Dispersal movements of yearling males represent the greatest risk for rapid spread of diseases from infected source populations. Disease management efforts in riparian habitats should target male fawns and yearling males for removal in areas within or immediately adjacent to river corridors. © 2011 The Wildlife Society.     

Cause-specific mortality of white-tailed deer as influenced by military training activities in southwestern Oklahoma.

Radio-telemetry was used to monitor movements and mortality of 56 white-tailed deer (Odocoileus virginianus) in response to intensive military training activities on West Range (18,000 ha), Fort Sill Military Reservation, Oklahoma. Cause-specific mortality was determined for 22 radio-collared deer, including adults (greater than or equal to 2.0-yr-old), yearlings (0.6-1.9-yr-old), and fawns (less than or equal to 75-day-old age group) from 1987 to 1989. Winter home ranges were largely confined to a 14,411 ha impact area centrally located on West Range. The mean annual mortality rate was 0.50 for adults and yearlings combined. Fifty percent of all adult and yearling mortality was attributed to military training activities, 28% to hunting, 16% to collisions with automobiles, and 6% to unknown causes. The mean monthly mortality rate was 0.61 for neonatal fawns and predation accounted for three of four mortalities. All captured deer in the greater than or equal to 2.6-yr-old, 82% in the 1.6-yr-old, 10% in the 0.6-yr-old, and all deer in the less than 7-day-old age groups were seropositive for bluetongue virus (BTV). Our study strongly suggests that the consequences of military training activities should be considered in the management of white-tailed deer herds on military installations.     

Experimental infection of white-tailed deer with Elaeophora schneideri.

An attempt was made to infect fawn and adult white-tailed deer, Odocoileus virginianus, with Elaeophora schneideri. Experimental infection of fawns caused a relative eosinophilia that persisted. Obstruction of a coronary artery caused death of one fawn, and weakness, dyspnea, and locomotor difficulties were observed in another fawn and an adult. Plaque-like lesions were observed grossly in the intimal lining of carotid arteries, and subintimal thickening and proliferation of fibrous tissue in vessel walls were observed microscopically. Nematodes were recovered from 3 of 4 fawns and 0 of 4 adults, suggesting an age-related resistance in older animals. Microfilariae were recovered via facial skin biopsy of a single fawn. This study suggests that white-tailed deer serve as usual hosts for E. schneideri, although the host-parasite relationship may be tenuous.     

Contributions of forage competition, harvest, and climate fluctuation to changes in population growth of northern white-tailed deer

Recently there has been considerable interest in determining the relative roles of endogenous (density-dependent) and exogenous (density-independent) factors in driving the population dynamics of free-ranging ungulates. We used time-series analysis to estimate the relative contributions of density-dependent forage competition, climatic fluctuation, and harvesting on the population dynamics of white-tailed deer (Odocoileus virginianus) in Nova Scotia, Canada, from 1983 to 2000. A model incorporating the population density 2 years previous, an interaction term for the harvest of females and population density 2 years previous, and the total snowfall during the previous 2 winters explained 80% of the variation in inter-annual population growth rate. Natality of adult females was negatively related to deer density during the present winter, whereas that of yearlings may have been correlated with the snowfall of three winters previous. Natality of fawns was related to deer density and total snowfall during the previous winter. Coyotes (Canis latrans) prey extensively on deer fawns in northeastern North America and the annual harvest of snowshoe hares (Lepus americanus), the major alternate prey of coyotes, explained 48% of the inter-annual variation in fawn recruitment. The proportions of fawn, yearling, and adult deer suffering from severe malnutrition during late winter were all correlated with deer density during the present winter. We conclude that the limiting effects of winter weather on over-winter survival of deer may be cumulative over two consecutive winters. During the late 1980s, density dependence and winter severity acted in concert to effect substantial declines in deer population growth both by effecting winter losses directly and by exacerbating predation by coyotes. During this period liberal harvesting did not relieve density-dependent forage competition and probably accelerated the decline.     

Prevalence of Sarcocystis in wolves and white-tailed deer in Northeastern Minnesota

The prevalence of Sarcocystis (Protozoa: Sarcocystidae) in white-tailed deer (Odocoileus virginianus) from northeastern Minnesota was determined by histologic examination of tongue samples. Seventy-nine of 100 deer were infected; infection was higher in yearlings and adults than in fawns. Sporocysts of Sarcocystis were found in 3% of 72 wolf (Canis lupus) scats. Three of four captive wolves fed muscle from a white-tailed deer naturally infected with Sarcocystis shed sporocysts 12-14 days later.     

White-Tailed Deer Population Dynamics Following Louisiana Black Bear Recovery

Changing predator communities have been implicated in reduced survival of white-tailed deer (Odocoileus virginianus) fawns. Few studies, however, have used field-based age-specific estimates for survival and fecundity to assess the relative importance of low fawn survival on population growth and harvest potential. We studied white-tailed deer population dynamics on Tensas River National Wildlife Refuge (TRNWR) in Louisiana, USA, where the predator community included bobcats (Lynx rufus), coyotes (Canis latrans), and a restored population of Louisiana black bear (Ursus americanus luteolus). During 2013–2015, we radio-collared and monitored 70 adult (≥2.5 yrs) and 21 yearling (1.5-yr-old) female deer. Annual survival averaged 0.815 (95% CI = 0.734–0.904) for adults and 0.857 (95% CI = 0.720–1.00) for yearlings. We combined these estimates with concurrently collected fawn survival estimates (0.27; 95% CI = 0.185–0.398) to model population trajectories and elasticities. We used estimates of nonhunting survival (annual survival estimated excluding harvest mortality) to project population growth (λ) relative to 4 levels of harvest (0, 10%, 20%, 30%). Finally, we investigated effects of reduced fawn survival on population growth under current management and with elimination of female harvest. Despite substantial fawn predation, the deer population on TRNWR was increasing (λ = 1.06) and could sustain additional female harvest; however, the population was expected to decline at 20% (λ = 0.98) and 30% (λ = 0.94) female harvest. With no female harvest, the population was projected to increase with observed (λ = 1.15) and reduced fawn survival (λ = 1.02), but the population could not sustain current female harvest (10%) if fawn survival declined (λ = 0.90). For all scenarios, adult female survival was the most elastic parameter. Given the importance of adult female survival, the relative predictability in response of adult survival to harvest management, and the difficulty in altering fawn survival, reducing female harvest is likely the most efficient approach to compensate for low fawn survival. On highly productive sites such as ours, reduction, but not necessarily elimination, of harvest can mitigate effects of low fawn survival on population growth. © 2020 The Wildlife Society.     

Winter fawn survival in black-tailed deer populations affected by hair loss syndrome

Overwinter fawn mortality associated with hair loss syndrome (HLS) is anecdotally thought to be important in declines of Columbian black-tailed deer (Odocoileus hemionus columbianus) populations in Washington and Oregon (USA). We determined prevalence of HLS in black-tailed deer, September and April fawn:doe ratios, and minimum overwinter survival rates of fawns for selected game management units (GMUs) in western Washington from 1999 to 2001. Prevalence of HLS ranged from 6% to 74% in fawns and 4% to 33% in does. Minimum fawn survival ranged from 0.56 to 0.83 and was unrelated to prevalence of HLS in either does (r=0.005, P=0.991) or fawns (r=-0.215, P=0.608). The prevalence of HLS in either does or fawns was also unrelated to either fall fawn:doe ratios (HLS does: r=-0.132, P=0.779; HLS fawns: r=0.130, P=0.760) or spring fawn:doe ratios (HLS does: r=-0.173, P=0.711; HLS fawns: r=-0.020, P=0.963). However, the prevalence of HLS in does and fawns was strongly related (r=0.942, P=0.002), and GMUs with high prevalence of HLS had lower deer population densities (fawns: r=-0.752, P=0.031; does: r=-0.813, P=0.026). Increased overwinter mortality of fawns because of HLS was not supported by our data. Decreased production of fawns, increased summer mortality of fawns, or both were seen in six of eight study GMU-year combinations. Observed rates of productivity and minimum fawn survival were inadequate to maintain population size in five of eight study GMU-year combinations, assuming an annual doe survival rate of 0.75. The influence of deer condition and population health on adult survival, fawn production, preweaning fawn survival, parasitism, and prevalence of HLS in both fawns and adults need to be clarified to identify what factors are limiting black-tailed deer productivity.     

Ticks on white-tailed deer fawns from southern Illinois

Seventy-six white-tailed deer (Odocoileus virginianus (Zimmermann] fawns captured on Crab Orchard National Wildlife Refuge in southern Illinois during June-July 1980-1983 were aged and examined for ticks. The prevalence of ticks (Amblyomma americanum (Linnaeus, 1758) and Dermacentor variabilis (Say, 1821] was 80%; intensity of infestation ranged from one to 123 ticks per fawn, averaging 21.6. Tick intensity correlated poorly with age suggesting that there were other, more important determinants of infestation rates. Packed cell volumes in blood of the fawns increased significantly with age, but were not significantly affected by existing tick intensities. Ticks were not directly or indirectly implicated in any of 16 mortalities that occurred among 61 radio-collared fawns monitored for approximately 6 mo post-partum, and were not considered a serious health problem for fawns on the study area.     

DISPERSAL BY YEARLING MALE WHITE-TAILED DEER AND IMPLICATIONS FOR MANAGEMENT

Abstract: The scale at which populations use the landscape influences ecological processes and management decisions. Dispersal and home-range size define the scale of landscape use for many large-mammal species. We measured dispersal and home-range size of yearling male white-tailed deer (Odocoileus virginianus) in southern Texas, and compared our results to values from the literature to understand the implications of dispersal in management of deer populations. We used radiotelemetry to monitor 22 yearling deer on 1 study site from October 1998 to October 1999, and 27 yearling deer on a second study site from October 1999 to October 2000. On the 2 study sites, 68% and 44% of yearling deer established new areas of use 4.4 ± 1.0 km and 8.2 ± 4.3 km, respectively, from the center of their autumn home range. Yearling males with spike antlers (2 points) were less likely to disperse than yearlings with fork antlers (>2 points) on 1 study site. Computer simulation showed that the scale at which deer use the landscape is large compared to property sizes in southern Texas and probably in other areas of the white-tailed deer's range. Differences in scale between land ownership patterns and landscape use by deer may result in a failure to meet management objectives and conflict among managers. High harvest rates for male deer occur in part because deer movements are large relative to property size, creating a “tragedy of the commons.” Cooperative management groups are beneficial if all landowners in an area agree on management objectives. Otherwise, deer-proof fences often are erected to reduce conflicts among property owners.     

Salmonellosis in white-tailed deer fawns

Experimental infection of white-tailed deer fawns with Salmonella meleagridis was accomplished. The fawns suffered clinical illness, similar to spontaneous cases observed in the field. This disease may be an important factor in fawn survival in wild herds based on the frequency with which Salmonellae could be isolated in wild fawns. The clinical disease was acute, characterized by rapid depression and dehydration. Death ensued in three of eight experimental cases. The survivors suffered clinical illness.     

Febrile response and decrease in circulating lymphocytes following acute infection of white-tailed deer fawns with either a BVDV1 or a BVDV2 strain

Although commonly associated with infection in cattle, bovine viral diarrhea viruses (BVDV) also replicate in many domestic and wildlife species, including cervids. Bovine viral diarrhea viruses have been isolated from a number of cervids, including mule deer (Odocoileus hemionus), European roe deer (Capreolus capreolus), red deer (Cervus elaphus), white-tailed deer (Odocoileus virginianus), and mouse deer (Tragulus javanicus), but little information is available regarding clinical presentation and progression of infection in these species. In preliminary studies of experimental infection of deer with BVDV, researchers noted seroconversion but no clinical signs. In this study, we infected white-tailed deer fawns that were negative for BVDV and for antibodies against BVDV, with either a type 1 or a type 2 BVDV that had been isolated from white-tailed deer. Fawns were monitored for changes in basal temperature, circulating lymphocytes, and platelets. The clinical progression following inoculation in these fawns was similar to that seen with BVDV infections in cattle and included fever and depletion of circulating lymphocytes. Because free-ranging cervid populations are frequently in contact with domestic cattle in the United States, possible transfer of BVDV between cattle and cervids has significant implications for proposed BVDV control programs.     

Prevalence of meningeal worm (Parelaphostrongylus tenuis) in white-tailed deer from New Hampshire

Parelaphostrongylus tenuis was found in 79 (62.2%) of 127 white-tailed deer heads (Odocoileus virginianus) collected in New Hampshire. Prevalence of infection was higher in fawns and male deer, but older female deer (5.0 + years) had a higher intensity of infection (3.1) than any other age or sex class. Male deer in forest cover type 2 (northern hardwoods-hemlock-white pine) had a significantly greater prevalence of infection than the females in the same habitat (P less than .05). Adult females had a higher prevalence of infection (67.0%) than female fawns (20%) in forest cover type 1 (spruce-fir-northern hardwoods). In the craniums examined, P. tenuis was found most frequently in the tentorium cerebelli (23.6%) while the falx cerebri, the most prevalent site of infection in fawns, was a significantly less frequent site of infection in older deer (P less than .02). Male deer of age class 3.5 years had a significantly higher rate of infection in the dura mater-olfactory lobe than any other age or sex group (P less than .02). The cavernous sinus was the most frequent site of parasitism in male fawns (25.0%) and was the second most common location in all deer (13.4%).     

Population-level response of coyotes to a pulsed resource event

From foraging theory, generalist predators should increase consumption of prey if prey availability increases. Pulsed resource events introduce a large influx of prey to predators that may exhibit a functional response of increased consumption rate on, or specialization to, this abundant food resource. We predicted that coyotes (Canis latrans) would respond functionally to numerical increases of neonate white-tailed deer (Odocoileus virginianus) during the pulsed resource event of parturition. We used howl surveys and deer camera surveys with occupancy modeling to estimate densities for coyotes, adult deer, and fawns, respectively, in Upper Peninsula of Michigan, USA, 2009–2011. We estimated biomass of adult and fawn deer consumed by coyotes during 2 periods [fawn limited mobility period (LMP) and social mobility period (SMP)] in May–August each year. Coyote densities were 0.32 and 0.37/km² for 2010–2011, respectively. Adult deer densities (3.7–3.9/km²) and fawn densities (0.6–1.3/km²) were similar across years. Overall, fawn hair occurrence in coyote scats was 2.3 times greater in LMP than SMP. Estimated consumption of fawns between periods (n = 157–880) by coyotes varied, suggesting a functional response, with increasing consumption of fawns relative to their availability. Coyotes, on average, consumed 2.2 times greater biomass of fawns than adults across years, and consumed 1.5 times greater fawn biomass, on average, during LMP than SMP. We suggest that consumption rates of coyotes is associated positively with increases in fawn density, and fawn consumption by coyotes follows predictions of optimal foraging theory during this pulsed resource event.     

Increased brown bear predation on sika deer fawns following a deer population irruption in eastern Hokkaido, Japan

By the 1970s, brown bears (Ursus arctos) in Hokkaido, northern Japan, were opportunistic omnivores that mainly depended on plant materials. Because the sika deer (Cervus nippon) population irrupted in eastern Hokkaido in the 1990s, we expected that brown bears might prey on sika deer fawns. First, we developed a simple and cost-effective method of monitoring possible bear predation on deer fawns by analyzing the widths of deer hairs remained in bear scats. Based on hair thickness standards, we distinguished the brown bear consumption of deer fawns from adults by analyzing bear scats (n?=?108) collected during the deer birthing season (late May?Clate July) in 1999?C2008. To evaluate the importance of fawns to bears, we compared the occurrence of fawn and adult deer hairs in bear scats among three periods (I, 1999?C2000; II, 2003?C2005; III, 2006?C2008) in eastern Hokkaido. The occurrence of fawn hairs in bear scats increased from 12.5 to 27.3?% in volume and from 6.3 to 33.6?% in frequency from period I to period III, whereas adult hairs in scats decreased from 42.8 to 26.1?% in volume and from 34.4 to 22.7?% in frequency during the same time. These data suggest that bears increasingly preyed on deer fawns after the deer population irruption and decreasingly used adult carcasses because of the enforcement of deer carcass treatment by the Hokkaido government.     

Occurrence of antibodies to the etiologic agents of infectious bovine rhinotracheitis, parainfluenza 3, leptospirosis, and brucellosis in white-tailed deer in Minnesota

A serologic survey was conducted on 628 white-tailed deer (Odocoileus virginianus) in 1976 and 1979-1980. Tests for antibodies to the etiologic agents of infectious bovine rhinotrancheitis (IBR), parainfluenza 3 (PI3), leptospirosis, and brucellosis produced positive results of 15%, 20%, 3% and 0%, respectively. Adult deer had significantly higher prevalence of antibodies to IBR virus and PI3 virus than fawns. These data provide a basis for monitoring these disease agents in Minnesota's white-tailed deer.     

Experimental adenovirus hemorrhagic disease in white-tailed deer fawns

Infection with a newly described endotheliotropic adenovirus was the cause of a 1993 epizootic reminiscent of hemorrhagic disease in California mule deer (Odocoileus hemionus columbianus and O. hemionus hemionus). Pulmonary edema and intestinal luminal hemorrhage, or necrotizing stomatitis associated with systemic or localized vasculitis, respectively, were common lesions seen in animals that died during the epizootic. In order to determine if white-tailed deer (Odocoileus virginianus) also are susceptible to infection and fatal disease with the deer adenovirus, eight white-tailed deer fawns (4- to 6-mo-old) were inoculated with purified deer adenovirus. Four were inoculated intravenously and four were inoculated through the mucous membranes. Seven days post-inoculation, one of the fawns inoculated intravenously died. Pulmonary edema and hemorrhagic enteropathy were associated with pulmonary and intestinal vasculitis with systemic multiorgan distribution of endotheliotropic adenovirus as demonstrated by transmission electron microscopy and immunohistochemistry. Adenovirus was reisolated from lung homogenates of the fawn that died of adenovirus hemorrhagic disease.