Congenital osteopetrosis in white-tailed deer (Odocoileus virginianus)

Inferior brachygnathia in neonatal fawns occurred sporadically over a 10 yr period in a captive herd of white-tailed deer (Odocoileus virginianus) in southern Ontario. Two fawns submitted for necropsy had marked inferior brachygnathia, protruding tongues, and fractured long bones. Radiographs of the limbs revealed longitudinal striations of relatively translucent immature woven bone that caused loss of distinction between medullary cavities and cortices. Microscopically, there was failure of remodelling of the primary spongiosa and filling of the medulla by cone-shaped chondro-osseous cores. The findings supported a diagnosis of osteopetrosis, usually a hereditary disease characterized by absence of marrow cavities as a result of defective bone remodelling. Osteopetrosis has not been reported previously in deer.     

Hyperkalemia in free-ranging white-tailed deer (Odocoileus virginianus)

Sixty adult and yearling female white-tailed deer (Odocoileus virginianus) were collected in July 2008 (n=30) and March 2009 (n=30) from eastern North Carolina as part of a population health assessment. During July 2008, standard serum analyses revealed hyperkalemia in all deer sampled. In March, the effect of processing time as a possible source of the hyperkalemia was investigated. For a subset of deer (n=10), blood tubes were centrifuged and processed at four time points (0, 30, 60, and 120 min) postcollection. Delayed centrifugation and plasma separation did not affect potassium (K(+)) concentration over time, indicating that a shift in intracellular K(+) did not occur and the hyperkalemia was not due to improper sample handling. Potassium levels were negatively correlated with age and varied across collection periods. Also, K(+) levels were positively correlated with glucose and not correlated with creatine kinase (CK). No single variable indicated a strong enough relationship to explain the hyperkalemia in the study.     

Staphylococcal arthritis in a white-tailed deer (Odocoileus virginianus)

A five and one-half year old deer (Odocoileus virginianus) developed an ankylosing periarticular hypertrophic arthritis due to a coagulase positive staphylococcus infection. Complete encasement of the tibio-tarsal (hock) joints with a hypertrophic, and porous osseous mass had occurred with complete loss of articular cartilage. The pathologic alterations of the tissues are compared to those occurring in swine due to Erysipelothrix insidiosa infection which produces a rheumatoid-like arthritis.     

Cranial osteochondroma in a white-tailed deer (Odocoileus virginianus)

A large osteochondroma of the skull was diagnosed in a young adult free-ranging white-tailed deer (Odocoileus virginianus) from Wyoming. The 4.8-kg neoplasm primarily involved the left frontal bone with extension into the cranial cavity. Microscopically, the neoplasm was composed of well differentiated trabecular bone and islands of cartilage. This neoplasm is rare in domestic species and has not been reported in cervids. Though benign in morphology, the location and size of the neoplasm was probably responsible for debilitation of the deer.     

Pulmonary mycoplasmosis in farmed white-tailed deer (Odocoileus virginianus)

An outbreak of respiratory disease at a farmed cervid facility resulted in isolation and identification of Mycoplasma boris in four affected white-tailed deer (Odocoileus virginianus) fawns. Microscopically, pulmonary lesions similar to those associated with M. bovis infections in calves, inclulding lymphoplasmacytic peribronchiolar cuffing and caseonecrotic bronchiectasis, were present. Arcanobacterium pyogenes was recovered from lung tissue as well. This report indicates that M. bovis can be associated with respiratory disease in white-tailed deer.     

Theileriosis in a white-tailed deer (Odocoileus virginianus) fawn

A white-tailed deer (Odocoileus virginianus) fawn was collected in Missouri (USA) and submitted for diagnostic evaluation. Necropsy and histologic examination revealed severe Amblyomma americanum infestation, pronounced icterus, and marked hemosiderin deposition in the liver and spleen. Whole blood evaluation revealed a normocytic normochromic anemia and a piroplasm parasitemia of approximately 70%. The piroplasm was identified as Theileria cervi by polymerase chain reaction and sequencing of the V4 variable region of the 18S rRNA gene from a paraffin-embedded section of lung. Although T. cervi parasitemias have been commonly reported in healthy white-tailed deer, the severe parasitemia in this fawn may have contributed to overt clinical disease, perhaps as part of a combined malnutrition and parasitemia syndrome.     

Maxillary lymphosarcoma in a white-tailed deer (Odocoileus virginianus)

In 1996, lymphosarcoma was observed in a captive adult female white-tailed deer (Odocoileus virginianus) from northeastern Kansas (USA). A subcutaneous mass on the deer's left cheek was surgically removed and lymphosarcoma was diagnosed. The mass recurred within 3 wk. A second surgical removal was attempted but the tumor had grown much larger, had become intimately involved with the buccal mucosa, and was beginning to interfere with mastication. For these reasons, the deer was euthanized. At postmortem examination the only abnormal findings were the primary tumor and enlarged ipsilateral parotid and mandibular lymph nodes. Histologically these tissues demonstrated changes characteristic of lymphosarcoma but no other organs had evidence of neoplastic disease. A diagnosis of focal lymphosarcoma with local metastasis was made. The organ distribution of lymphosarcoma in this deer differs from previously described cases of lymphosarcoma in cervids.     

Cranial suture complexity in white-tailed deer (Odocoileus virginianus)

Neurocranial expansion and mastication are commonly implicated as the two major biomechanical factors affecting suture morphology. In deer the antlers provide an additional source of biomechanical stress acting on the skull. Equivalent stresses are not found in females, who lack antlers. We analyzed the complexity and interdigitation of the interfrontal and coronal sutures that surround the antler-bearing frontal bones of (n = 67) white-tailed deer (Odocoileus virginianus) to 1) evaluate changes in suture morphology throughout ontogeny, and 2) test the hypothesis that male deer have more complex sutures than females. Two methods were used to quantify suture morphology: fractal analysis and length-ratios (actual suture length divided by direct straightline length). Both techniques produced similar results, although the two methods cannot be considered equivalent. Suture complexity increases markedly throughout ontogeny, but appears to level off after animals have reached adulthood. Cranial size in males, but not females, continues to increase in adults. No significant increase in suture complexity with age in the adult cohort was detected. While deer are highly dimorphic in size and the presence of antlers, no significant differences existed between males and females for any measure of suture complexity. No consistent patterns emerged between suture complexity and skull size or antler characteristics. The presence of antlers appears to have a minimal effect on suture complexity in white-tailed deer. Factors that may contribute to the lack of dimorphism in suture complexity are discussed.     

Aerosol exposure of white-tailed deer (Odocoileus virginianus) to Mycobacterium bovis

Tuberculosis due to Mycobacterium bovis affects both captive and free-ranging Cervidae in the United States. Various animal models have been developed to study tuberculosis of both humans and animals. Generally, tuberculosis is transmitted by aerosol and oral routes. Models of aerosol exposure of large animals to M. bovis are uncommon. In order to develop a reliable method of aerosol exposure of white-tailed deer (Odocoileus virginianus) to M. bovis, 12 healthy white-tailed deer, aged 8-10 mo, were infected by aerosol exposure to 2 x 10(5) to 1 x 10(6) colony forming units (CFU) (high close, n = 4) of M. bovis or 6 x 10(2) to 1.6 x 10(3) CFU (low dose, n = 8) of M. bovis. Tuberculous lesions were more widely disseminated in (leer receiving the high dose, while lesions in deer receiving the low dose were more focused on the lungs and associated lymph nodes (tracheobronchial and mediastinal). Aerosol delivery of M. bovis to white-tailed deer results in a reliable manner of experimental infection that may be useful for studies of disease pathogenesis, immune response, mycobacterial shedding, and vaccine efficacy.     

Experimental infection of white-tailed deer (Odocoileus virginianus) with Mycobacterium avium subsp. paratuberculosis

Mycobacterium avium subsp. paratuberculosis (Map) is the causative agent of paratuberculosis or Johne's disease, a chronic enteric disease of domestic ruminants as well as some nondomestic ruminants. Paratuberculosis is characterized by a protracted subclinical phase followed by clinical signs such as diarrhea, weight loss, and hypoproteinemia. Fecal shedding of Map is characteristic of both the subclinical and clinical phases, and it is important in disease transmission. Lesions of paratuberculosis are characterized by chronic granulomatous enteritis and mesenteric lymphadenitis. Animal models of paratuberculosis that simulate all aspects of the disease are rare. Oral inoculation of 9-day-old white-tailed deer (Odocoileus virginianus) on 3 June 2002 with 1.87 x 10(10) colony-forming units of Map strain K10 resulted in clinical disease (soft to diarrheic feces) as early as 146 days after inoculation; lesions consistent with paratuberculosis were observed in animals at the termination of the study. Intermittent fecal shedding of Map was seen between 28 and 595 days (4 March 2004) after inoculation. These findings suggest that experimental oral inoculation of white-tailed deer fawns may mimic all aspects of subclinical and clinical paratuberculosis.     

Atlantoaxial instability in a white-tailed deer fawn (Odocoileus virginianus)

On 14 March 2001, an 8 mo old, male white-tailed deer (Odocoileus virginianus) was found in lateral recumbency exhibiting neurologic signs including inability to rise, opisthotonus, paddling, and respiratory distress. There was evidence of minor cranial trauma. Postmortem examination revealed atlantoaxial instability with ventral deviation of the axis due to malformation of the caudal atlas and cranial axis. Given the age of the fawn, the instability was assumed to be congenital with minor trauma inducing severe, acute neurologic signs.     

Innate resistance to epizootic hemorrhagic disease in white-tailed deer

Differences in innate disease resistance at the sub-species level have major implications for wildlife management. Two subspecies of white-tailed deer, Odocoileus virginianus borealis and O. virginianus texanus were infected with epizootic hemorrhagic disease (EHD) viruses. These viruses are highly virulent pathogens of white-tailed deer and are endemic within the range of O. virginianus texanus but not within the range of O. virginianus borealis. Two experimental infections were performed. Five O. virginianus texanus fawns and five O. virginianus borealis fawns were infected with 10(7.1) median tissue culture infective doses (TCID50) of EHD virus, serotype 1 and five of each subspecies were infected with 10(7.1) TCID50 of EHD virus, serotype 2. Infections with both EHD virus serotypes caused severe clinical disease and mortality in O. virginianus borealis fawns, whereas disease was mild or nondetectable in O. virginianus texanus fawns. Virus titers and humoral immune response were similar in both subspecies suggesting that differences in innate disease resistance explain the differences seen in clinical disease severity. In white-tailed deer, innate disease resistance may vary at the subspecies level. Should this phenomenon occur in other species, these findings have major implications for managing wildlife populations, both endangered and non-endangered, using tools such as translocation and captive propagation.     

Effects of fluoride ingestion on white-tailed deer (Odocoileus virginianus)

The effects of the addition of 25 or 50 ppm fluoride (F), as sodium fluoride (NaF), to the rations of 5-mo-old male white-tailed deer were similar to those observed in domestic cattle fed similar amounts of fluoride. The ingestion of 50 ppm F for 2 yr resulted in the accumulation of over 7,000 ppm F in bone ash. Accumulation of fluoride in antlers was extensive and occurred more rapidly than in skeletal tissue. Fluoride ingestion resulted in lesions on the developing incisors that were similar, but not identical to those seen in other species. Increased molar wear in the deer fed 50 ppm F was minimal, and no gross pathology of the mandible was observed. Only mild hyperostosis of the long bones was evident.     

Experimental infection of white-tailed deer (Odocoileus virginianus) with Ehrlichia chaffeensis by different inoculation routes

The infection dynamics of the tick-transmitted organism Ehrlichia chaffeensis were investigated in white-tailed deer (Odocoileus virginianus) using different routes of inoculation. Six deer were each inoculated with 5.4 x 10(6) DH82 cells infected with E. chaffeensis (Arkansas strain) by three different routes: intravenous (n = 2), subcutaneous (n = 2), and intradermal (n = 2). Two control deer were inoculated with uninfected cells. Infections were monitored for 54 days and were continued in one deer from each E. chaffeensis inoculated group for an additional 31 days. All deer inoculated with E. chaffeensis seroconverted (> or = 1: 64) and became 16S rDNA polymerase chain reaction and/or cell culture positive by post-inoculation day 15. There was no apparent (difference in susceptibility to infection between deer inoculated by different routes for the first 50 days based on detection of E. chaffeensis infection by PCR assay of blood or culture isolation. These results demonstrate infection of (deer by intradermal and subcutaneous routes for the first time.     

Xylazine hydrochloride for immobilizing captive white-tailed deer (Odocoileus virginianus)

White-tailed deer (Odocoileus virginianus) were immobilized with intramuscular doses of xylazine hydrochloride to facilitate blood sampling. Injection was either remotely by modified dart syringe or manually by hand syringe. In 86 attempts to immobilize female deer (aged 2, 5–6 yr) 73.3% were effectively immobilized for 90 min while 108 attempts to immobilize male deer (aged 2–3 yr) for at least 30 min resulted in 94.4% effective immobilization. Induction times averaged approximately 10 min for both sexes. Treated deer exhibited sedation, hypothermia, reduced respiration rates, anorexia, salivation, tongue paralysis and diarrhea. Deer also showed a loss or partial loss of pedal, palpebral, corneal, and swallowing reflexes during immobilization. Side effects of xylazine and length of immobilization appeared to be dose dependent. Mortality as a result of xylazine immobilization was four male deer out of a total of 194 immobilizing attempts on both sexes. Recommendations are given concerning care of deer during immobilization and recovery.     

Oral and fecal shedding of epizootic hemorrhagic disease virus, serotype 1 from experimentally infected white-tailed deer

Epizootic hemorrhagic disease (EHD), one of the most important infectious diseases of white-tailed deer (Odocoileus virginianus), is vectored by species of midges in the genus Culicoides. Although vector borne, fecal shedding of EHD virus, serotype 2 has been reported from infected deer in a previous study. To evaluate the potential for fecal and oral shedding, oral and rectal swabs were obtained on day 8 post-inoculation from white-tailed deer fawns experimentally infected with EHD virus, serotype 1 (EHDV-1). Eight deer were viremic for EHDV-1; virus was detected in oral swabs from three (38%) and in rectal swabs from four (50%). The ability to isolate EHDV-1 in oral secretions or feces was not dependent on being able to detect clinical disease. These results indicate that in a relatively large proportion of EHDV-1 infected deer, virus can be detected in feces and oral secretions. Although more work is necessary, such shedding may be important in experimental studies or pen situations where deer-to-deer contact is prevalent and intense.     

Genetic consequences of white-tailed deer (Odocoileus virginianus) restoration in Mississippi

White-tailed deer (Odocoileus virginianus) were nearly extirpated from the southeastern USA during the late 19th and early 20th centuries. Recovery programmes, including protection of remnant native stocks and transplants from other parts of the species' range, were initiated in the early 1900's. The recovery programmes were highly successful and deer are presently numerous and continuously distributed throughout the southeastern USA. However, the impact of the recovery programmes on the present genetic structure of white-tailed deer remains to be thoroughly investigated. We used 17 microsatellite DNA loci to assess genetic differentiation and diversity for 543 white-tailed deer representing 16 populations in Mississippi and three extra-state reference populations. There was significant genetic differentiation among all populations and the majority of genetic variation (> or = 93%) was contained within populations. Patterns of genetic structure, genetic similarity and isolation by distance within Mississippi were not concordant with geographical proximity of populations or subspecies delineations. We detected evidence of past genetic bottlenecks in nine of the 19 populations examined. However, despite experiencing genetic bottlenecks or founder events, allelic diversity and heterozygosity were uniformly high in all populations. These exceeded reported values for other cervid species that experienced similar population declines within the past century. The recovery programme was successful in that deer were restored to their former range while maintaining high and uniform genetic variability. Our results seem to confirm the importance of rapid population expansion and habitat continuity in retaining genetic variation in restored populations. However, the use of diverse transplant stocks and the varied demographic histories of populations resulted in fine-scale genetic structuring.     

Gastro-intestinal helminths in white-tailed deer (Odocoileus virginianus) of Illinois.

Two deer populations, one in northern Illinois the other in southern Illinois, were examined by necropsy (n = 44 and 40 respectively) for helminth parasites of the gastro-intestinal tract and abdominal cavity. Both herds were parasitized by Apteragia odocoilei, Haemonchus contortus, Gongylonema pulchrum, Setaria yehi, Trichuris ovis, and Moniezia benedeni. Nematodirus sp. was found only in deer of northern Illinois. Ostertagia mossi, Capillaria sp., Cooperia sp., and Oesophagostomum sp. were found only in deer of southern Illinois.