Shelli A. Dubay

Disappearance of bovine fetuses in northwestern Wyoming

Abstract Brucellosis is a bacterial disease of cattle that has become established in elk (Cervus elaphus nelsoni) and bison (Bos bison) of the Greater Yellowstone Area. It causes pregnant elk and bison to abort, and the aborted fetus has the potential to transmit the pathogen to disease-free domestic cattle. We examined how long healthy bovine fetuses, as surrogates for aborted bison or elk fetuses, remained in the environment and could be available for contact by elk, bison, and cattle. Disease-free bovine fetuses were placed on Wyomings National Elk Refuge, state of Wyoming elk feedgrounds, and Grand Teton National Park to simulate aborted elk or bison fetuses. We monitored the fetuses until they disappeared due to scavenging. Fetuses disappeared on average in 26.8 hours (SD=25.3 hours) from the National Elk Refuge, 40.7 hours (SD=31.1 hours) at state elk feed-grounds, and 57.5 hours (SD=48.0 hours) at Grand Teton National Park. Ninety percent of fetuses can be expected to disappear from the National Elk Refuge within 69.5 hours (2.9 days), from state elk feedgrounds within 68.5 hours (2.9 days), and from Grand Teton National Park within 142 hours (5.9 days). The dominant scavengers at all locations were coyotes (Canis latrans), but ravens (Corvus corax), magpies (Pica pica), bald eagles (Haliaeetus leucocephalus), golden eagles (Aquila chrysaetos), turkey vultures (Cathartes aura), red-tailed hawks (Buteo jamaicensis), black bears (Ursus americanus), grizzly bears (U. arctos), and probably elk and bison also participated in scavenging.

ASSOCIATION OF MORAXELLA OVIS WITH KERATOCONJUNCTIVITIS IN MULE DEER AND MOOSE IN WYOMING

Six cases of infectious keratoconjunctivitis (IKC) in mule deer (Odocoileus hemionus) and moose (Alces alces) in Wyoming (USA) were investigated during fall and winter of 1995 and 1996. Excessive lacrimation, mucopurulent conjunctivitis, keratitis, and corneal opacity were observed in mule deer. Moose had severe mucopurulent conjunctivitis, keratitis, and corneal ulceration. Hemolytic, non-piliated Moraxella ovis was isolated from two mule deer and two moose. We attempted to reproduce IKC in three mule deer fawns using an isolate of M. ovis from a clinically affected mule deer. These fawns did not develop clinical signs of infection and the bacterium was not reisolated from inoculated deer. Inoculated deer may not have developed clinical signs because deer were not exposed to ultraviolet light or mechanical insult before inoculation. In addition, the isolate used for inoculation may have lost virulence factors through passage, or M. ovis may not have been the primary pathogen responsible for clinical disease in the natural cases of IKC we investigated. The etiology of IKC in free-ranging wild ruminants remains poorly understood.

Strongyloides robustus and the Northern Sympatric Populations of Northern (Glaucomys sabrinus) and Southern (G. volans) Flying Squirrels

Within North America, northern (Glaucomys sabrinus) and southern (Glaucomys volans) flying squirrels occupy distinct ranges with limited overlap. Sympatry in northern latitudes coincides with northern hardwood vegetation from Minnesota to New England. Strongyloides robustus is an intestinal parasite that infects both species but appears to be deleterious only to northern flying squirrels. As a result, S. robustus could be a critical determinant of flying squirrel population characteristics in at least some areas of sympatry. However, cold weather could potentially limit the distribution of S. robustus in northern climates. Therefore, we assessed fecal samples from both flying squirrel species to determine the presence of the nematode in Wisconsin. Strongyloides robustus was found in 12 flying squirrel scat samples and infected 52% of southern flying squirrels and 11% of northern flying squirrels. Prevalence of S. robustus infection for northern flying squirrels was substantially lower than previously reported from more southern regions. This is the northernmost documentation of S. robustus in flying squirrels and the first documentation of S. robustus parasitizing flying squirrels in Wisconsin.

Epizootiology of Hemorrhagic Disease in Mule Deer in Central Arizona

We report two male mule deer (Odocoileus hemionus) mortalities that occurred near Prescott, Arizona (USA) in September 2001. Necropsy lesions were compatible with those described for hemorrhagic disease (HD). Bluetongue (BTV) and epizootic hemorrhagic disease (EHDV) viral RNA were identified in tissues from one deer and EHDV viral RNA was identified in the other via reverse transcription-polymerase chain reaction (RT-PCR). Virus isolation attempts were unsuccessful in both cases. To determine geographic range and viral serotypes involved, we collected blood samples from healthy hunter-harvested male mule deer in three game management units near Prescott in October 2001. Forty-one blood samples were collected and antibodies against EHDV and/or BTV were found in 21/41 (51%) samples as determined by agar immunodiffusion. Serum neutralization test results suggest that multiple EHDV and BTV serotypes are present in Arizona.

Bacteria and nematodes in the conjunctiva of mule deer from Wyoming and Utah.

Swabs of conjunctiva were collected from 44 live and 226 hunter-harvested mule deer (Odocoileus hemionus) from Wyoming and Utah (USA). We identified 29 Gram negative and 22 Gram positive bacterial taxonomic categories, but many isolates from hunter-harvested animals were environmental contaminants. Staphylococcus spp. and Micrococcus spp. were the most common Gram positive bacteria isolated, and Enterobacter spp., Escherichia coli, and Pseudomonas spp. were common Gram negative bacteria isolated. Thelazia californiensis were found in 15% of hunter-harvested deer in Utah in 1994 and in 8% in 1995. Nematodes were found in 40% of live deer in 1995 and 66% in 1996. Three live animals showed clinical signs of infectious keratoconjunctivitis (IKC) in 1996, but pathogenic bacteria were not isolated from these individuals. Hemolytic, non-piliated Moraxella ovis was isolated from two clinically normal live deer in 1996 and isolates were similar to those cultured from IKC cases from Wyoming and Utah.

Determining Prevalence of Bluetongue and Epizootic Hemorrhagic Disease Viruses in Mule Deer in Arizona (USA) Using Whole Blood Dried on Paper Strips Compared to Serum Analyses

We investigated the feasibility of using whole blood dried on paper strips as a means to collect antibody prevalence data for the epizootic hemorrhagic disease viruses (EHDV) and bluetongue viruses (BTV) from hunter-harvested male mule deer (Odocoileus hemionus) in October 2002 from Arizona, USA. We compared antibody prevalence estimates in mule deer from paired paper strip and serum samples. Prevalence data obtained from elution of dried blood on paper strips proved to be consistent with results from serum in 94% of the samples tested. The paper strip method allows easy collection of blood from dead animals, with a smaller amount of blood being needed for analyses. Also, samples do not need to be refrigerated before analyses. We also used serum samples to determine hemorrhagic disease (HD) serotype exposure status of mule deer harvested from 4 distinct areas in Arizona. Antibodies to BTV and EHDV were identified in 3 of the 4 areas, with positive results to EHDV-1, EHDV-2, BTV-10, and BTV-11 being most common. Many animals did not have antibodies against the BTV serotypes. Exposure varied geographically and potentially with elevation. Hemorrhagic disease viruses commonly infect Arizona mule deer, except on the Kaibab Plateau in northern Arizona.

Serologic Survey for Pathogens Potentially Affecting Pronghorn (Antilocapra Americana) Fawn Recruitment in Arizona, USA

During the 1990s, pronghorn (Antilocapra americana) populations declined in Arizona, USA. To investigate potential causes of decline, we collected blood samples from hunter-harvested male pronghorn from 2001 to 2003 on four Arizona sites. Sera were tested for antibody to parainfluenza virus type 3 (PI3), bovine viral diarrhea virus, infectious bovine rhinotracheitis virus, bovine respiratory syncytial virus, epizootic hemorrhagic disease virus (EHDV), bluetongue virus (BTV), and Chlamydia psittaci. Antibody against PI3 was found in 33% of the samples, whereas antibody against BTV/EHDV was found in 77%. Antibodies to other pathogens were found at low prevalence rates. Although pronghorn decline in Arizona is probably not directly related to disease, potential reproductive effects of BTV/EHDV and PI3 infection on pronghorn in Arizona merit further study.

Influence of Environmental Variables on Baylisascaris procyonis Infection in Raccoons

Abstract: Baylisascaris procyonis is a zoonotic nematode commonly found in raccoons (Procyon lotor). Human-altered landscapes can support dense populations of raccoons, increasing the potential for interaction between humans and these animals. We used raccoon feces provided by licensed fur trappers to investigate environmental variables that influence prevalence of B. procyonis at 2 sites in Wisconsin. Trappers submitted raccoon feces to us, along with information on sex, age (juvenile and adult), and approximate trap location for each animal. We used zinc sulfate (1.18 specific gravity) flotation to detect B. procyonis eggs in approximately 1 g of fecal matter from each host. We used ArcView software to determine the distance of each trap location to an urban area as determined by the U.S. Census Bureau in 2000. We compared the habitat components in buffered home ranges (0.805 km around trap locations) of infected animals with those from uninfected animals using Mann-Whitney U-tests (P < 0.05). Variables investigated were human population, road density, housing units per census block, and land cover, including area of agriculture, forest, developed, shrubland, water, and grassland. We positively identified eggs in 64.9% of the animals sampled. Raccoons infected with B. procyonis had significantly larger area of agricultural habitats and significantly smaller areas of forested habitats in buffered home ranges than uninfected individuals. We found that raccoons near Madison and Milwaukee, Wisconsin, are commonly infected with B. procyonis, indicating that public education regarding protection from disease is warranted.

Parasite Infections in Nestling Red-Shouldered Hawks (Buteo lineatus) in Northeast Wisconsin

Abstract Red-shouldered hawks (Buteo lineatus) are threatened in Wisconsin and long-term data suggest that nest productivity is low in the state for unknown reasons. Our objective was to determine whether red-shouldered hawks in northeast Wisconsin were infected with parasites that could contribute to low nest productivity. We examined nestlings for the presence of Trichomonas gallinae, Protocalliphora avium, and blood parasites in June 2006 and 2007. We did not detect T. gallinae in throat swabs taken from 24 nestlings in 2007. Ear canals of nestlings were parasitized by P. avium larvae in 10 of 11 (91%) nests and in 22 of 24 (92%) nestlings. Larvae were found in higher intensity in 1 ear relative to the other. Leucocytozoon toddi was present in 90.5% (38/42) of the nestlings. At least 1 bird in each nest was infected. Intensity of L. toddi averaged 48.6 ± 58.3 infected cells per 2,000 erythrocytes (2.4 ± 2.9%). No other blood parasites were identified.

Prevalence and Intensity of Nematode Parasites in Wisconsin Ermine

Abstract: In the midwestern United States, ermine (Mustela erminea) are economically important because they are legally harvested for pelts. Information on parasites of ermine is lacking, and the effects that nematode parasites have on body condition of ermine hosts are unknown. We identified Skrjabingylus nasicola and Filaroides martis in ermine trapped from 2007 to 2013 from 6 counties in Wisconsin. Small mammals, commonly consumed by ermine, serve as paratenic hosts for both parasites. Our goal was to identify how age and sex of ermine, along with year, influence nematode parasitism. We also investigated how infection affected body condition for male and female ermine using body mass standardized by length as an index of body condition. We commonly found S. nasicola and F. martis in male and female ermine, but both prevalence and intensity of infection were higher for males. Relative to juveniles (<1 yr), adult (>1 yr) male ermine did not exhibit significantly higher intensity or prevalence of either parasite. We found that body condition was not compromised by infection for either sex, and intensity of S. nasicola and prevalence of F. martis were highest during the 2010–2011 trapping season. Of the 6 yr studied, precipitation was highest during the summer before the 2010–2011 season, and increased precipitation can cause increases in populations of gastropod intermediate hosts. We think that several distinct natural history components, namely, mating structure, diet, and metabolic rate, influence nematode parasitism in ermine.