Free-ranging White-tailed Deer Research Articles

Two Cases of Uterine Prolapse in Free-ranging Deer in South Dakota

Limited information exists pertaining to the occurrence of uterine prolapse in free-ranging white-tailed deer and mule deer. We report a case of uterine prolapse in a free-ranging white-tailed deer (Odocoileus virginianus) in northeastern South Dakota and a free-ranging mule deer (Odocoileus hemionus) in central South Dakota.

Live-trapping and bovine tuberculosis testing of free-ranging white-tailed deer for targeted removal

Context Significant efforts have been made in Michigan, USA, to reduce the prevalence of bovine tuberculosis (TB) in free-ranging white-tailed deer (Odocoileus virginianus) over the past 15 years. Since 2002, however, prevalence has changed little, prompting the need for new control strategies. Aims In January–March of 2007 and 2008, a trap–test–cull project was conducted on an 11 000-ha property in the north-eastern Lower Peninsula of Michigan. The objectives were to assess the feasibility of live-trapping and testing white-tailed deer for TB as a means for targeted removal and estimate the cost of this effort. Methods Live-trapped deer were ear-tagged and a blood sample was drawn for use with the CervidTB STAT-PAK (commonly called Rapid Test) for TB diagnosis in the field. Deer testing negative were released, whereas deer testing positive were euthanised to confirm blood-test results via bacterial culture. Key results In all, 762 (741 with known sex and age) individual deer were captured and tested for TB. Adults comprised 59% (437 of 741) of the captures. Eight (1.8%) adults were positive on the blood test; six of eight (1.4% of adults) were confirmed TB positive via bacterial culture. Estimated TB prevalence in the present study was 2.5% (adjusted for Rapid Test sensitivity of 56%), being lower than what would be expected on the basis of routine hunter-harvest surveillance for this site which has yielded prevalence rates from 3.4% to 4.8%. Results demonstrated the ability to trap and test a substantial number of deer given high deer densities (16–20 deer per km2), availability of traps and abundant workers. The 2-year project cost a total of ~US$228 000, or US$38 000 per culture-positive animal. Conclusions Because of the cost and effort involved, a project such as the present one applied to Michigan’s larger TB-management area (148 018 ha) is not feasible. Implications If the efficiency and effectiveness of a trap–test–cull project could be improved by vaccinating test-negative animals, should a vaccine be approved for use in free-ranging white-tailed deer, a trap–test–cull project applied on a scale similar to the present study may prove beneficial by possibly reducing disease transmission, in addition to removing TB-positive animals.

Molecular Study of Free-ranging Mule Deer and White-tailed Deer from British Columbia, Canada, for Evidence of Anaplasma spp. and Ehrlichia spp.

Twenty-three free-ranging white-tailed deer (WTD; Odocoileus virginianus) and six mule deer (MD; Odocoileus hemionus) from south-central British Columbia, Canada, were tested for Anaplasma marginale by msp5 gene-specific PCR and Ehrlichia spp. by 16S rRNA or citrate synthase (gltA) gene-specific PCR, as well as by PCR with universal 16S rRNA primers detecting a wide range of bacteria. No deer tested positive for A.marginale. Amplification with universal 16S rRNA primers followed by sequencing of cloned fragments detected an Anaplasma sp. in one of 23 (4.3%) WTD and six of six (100%) MD and Bartonella sp. in four of 23 (17.4%) WTD. The Anaplasma sp. was genetically distinct from A.marginale and all other recognized members of the genus. Four of six (66.7%) MD and 0 of 23 (0%) WTD were Ehrlichia positive by PCR with primers for 16S rRNA and gltA genes. The sequences of gltA PCR fragments were identical to each other and to the respective region of the gltA gene of an Ehrlichia sp. which we detected previously in naturally infected cattle from the same area, suggesting the possibility of biological transmission of this rickettsia between cattle and wild cervids. Antibodies reactive with the MSP5 protein of A.marginale were detected using a competitive enzyme-linked immunosorbent assay in two of six (33.3%) MD, but not in WTD. The two seropositive MD were PCR positive for both the Anaplasma sp. and Ehrlichia sp. detected in this study, suggesting a reaction of antibodies against one or both of these rickettsias with the MSP5 antigen.

Using Wild White-Tailed Deer to Detect Eastern Equine Encephalitis Virus Activity in Maine

Serum from 226 free-ranging white-tailed deer (Odocoileus virginianus) was screened for Eastern Equine Encephalitis Virus (EEEV) antibodies using plaque reduction neutralization tests. EEEV antibodies were detected in 7.1% of samples. This is the first time EEEV antibodies have been detected in O. virginianus populations in the state of Maine (ME). The highest percentage of EEEV positive sera was in Somerset County (19%) in central ME, and this is the first time that EEEV activity has been detected in that County. EEEV RNA was not detected in any of the 150 harvested deer brain samples submitted to the ME Department of Inland Fisheries and Wildlife as a part of screening for Chronic Wasting Disease. This suggests that screening deer brains is not an efficient method to detect EEEV activity. For each serum sample tested, the geographic location in which the deer was harvested was recorded. Significant spatial clustering of antibody-positive sera samples was not detected. Relative to seronegative deer, seropositive deer were slightly more likely to be harvested in nonforested areas compared with forested areas. Results indicate that screening of free-ranging deer sera can be a useful tool for detecting EEEV activity in ME and other parts of North America.

Biochemical Variables in Free-ranging White-tailed Deer (Odocoileus virginianus) after Chemical Immobilization in Clover Traps or Via Ground-darting

The objective of this prospective observational cohort study in free-ranging female white-tailed deer (Odocoileus virginianus) was to compare the physiologic effects of two methods of anesthetic drug administration: hand-injection in Clover traps and remote injection by dart after ground-stalking. Six trapped and 14 darted female deer were injected with a median (minimum, maximum) of 590 microg/kg butorphanol (401, 1070 microg/kg), plus 235 microg/kg medetomidine (160, 429 microg/kg) intramuscularly. In the trap, the deer struggled when approached and were restrained for injection. Darted deer sprinted away after injection. Once immobilized, deer were transported to a veterinary hospital where blood was collected and vital signs were measured on admission. Admission data from a subset of deer in which measurements were taken within 40 min of trapping (n = 6) or darting (n = 5) were analyzed. After salpingectomy under isoflurane and while still anesthetized, another blood sample was collected from all 20 deer. Body weight and immobilization drug doses were not different between groups. On admission, most deer from both groups were hypoxemic, although the darted deer were significantly more hypoxemic. The median rectal temperature in trapped deer was higher than in darted deer, and temperatures higher than 39 degrees C only occurred in trapped deer. The median heart rate in trapped deer was more than twice that in darted deer. Trapped deer had lower median pH and base excess; in trapped deer, the median plasma lactate concentration was more than fivefold higher than in darted deer. After surgery, the median serum creatine kinase concentration was nearly 10-fold higher in trapped deer, and the median cardiac troponin I concentration was higher in trapped deer but undetectable in 10 of 14 darted deer. The white-tailed deer immobilized by hand-injection in Clover traps experienced more severe physiologic perturbations than deer remotely injected by dart after ground-stalking. These perturbations might be sufficient to cause myocardial damage.

Public acceptance as a determinant of management strategies for bovine tuberculosis in free-ranging U.S. wildlife

When bovine tuberculosis (bTB) is detected in free-ranging wildlife populations, preventing geographic spread and the establishment of a wildlife reservoir requires rapid, often aggressive response. Public tolerance can exert a significant effect on potential control measures available to managers, and thus on the success of disease management efforts. Separate outbreaks of bTB in free-ranging white-tailed deer ( Odocoileus virginianus) in two midwestern states provide a case study. In Minnesota, bTB was first discovered in cattle in 2005 and subsequently in deer. To date, 12 beef cattle farms and 26 white-tailed deer have been found infected with the disease. From 2005 to 2008, disease prevalence in deer has decreased from 0.4% (SE = 0.2%) to <0.1% and remained confined to a small (<425 km 2) geographic area. Deer population reduction through liberalized hunting and targeted culling by ground sharpshooting and aerial gunning, combined with a prohibition on baiting and recreational feeding, have likely been major drivers preventing disease spread thus far. Without support from cattle producers, deer hunters and the general public, as well as politicians, implementation of these aggressive strategies by state and federal authorities would not have been possible. In contrast, Michigan first discovered bovine bTB in free-ranging deer in 1975, and disease management efforts were not instituted until 1995. The first infected cattle herd was diagnosed in 1998. Since 1995, disease prevalence in free-ranging deer has decreased from 4.9% to 1.8% in the ∼1500 km 2 core outbreak area. Culture positive deer have been found as far as 188 km from the core area. Liberalized harvest and restrictions on baiting and feeding have facilitated substantial reductions in prevalence. However, there has been little support on the part of hunters, farmers or the general public for more aggressive population reduction measures such as culling, and compliance with baiting and feeding restrictions has been variable and often problematic. We compare and contrast the Minnesota and Michigan outbreaks with respect to temporal, social, economic, and logistical factors that shape public attitudes toward aggressive disease control strategies, the limitations these factors place on management, and the implications for bTB eradication from wildlife reservoirs in the U.S.

Preventing the establishment of a wildlife disease reservoir: a case study of bovine tuberculosis in wild deer in Minnesota, USA.

Bovine tuberculosis (bTB) has been found in 12 cattle operations and 27 free-ranging white-tailed deer (Odocoileus virginianus) in northwestern Minnesota, following the state's most recent outbreak of the disease in 2005 in the northwest part of the state. Both deer and cattle have the same strain of bTB. The Minnesota Board of Animal Health has been leading efforts to eradicate the disease in Minnesota's cattle, which have included the depopulation of all infected herds, a cattle buy-out program, and mandatory fencing of stored feeds. The Minnesota Department of Natural Resources began surveillance efforts in free-ranging white-tailed deer in fall 2005. All bTB-infected deer have been found within a 16 km2 area in direct association with infected cattle farms. Aggressive efforts to reduce deer densities through liberalized hunting and sharpshooting have resulted in a 55% decline in deer densities. Also, recreational feeding of wild deer has been banned. Disease prevalence in deer has decreased from 1.2% in 2005 to an undetectable level in 2010.

Lesion Distribution and Epidemiology ofMycobacterium bovisin Elk and White-Tailed Deer in South-Western Manitoba, Canada

Surveillance for Mycobacterium bovis in free-ranging elk (Cervus elaphus) and white-tailed deer (Odocoileus virginianus) from south-western Manitoba was carried out from 1997 to 2010 to describe the lesions, epidemiology, and geographic distribution of disease. Tissues were cultured from animals killed by hunters, culled for management, blood-tested, or found opportunistically. Period prevalence in elk was approximately six times higher than deer, suggesting a significant reservoir role for elk, but that infected deer may also be involved. Prevalence was consistently higher in elk compared to deer in a small core area and prevalence declines since 2003 are likely due to a combination of management factors instituted during that time. Older age classes and animals sampled from the core area were at significantly higher risk of being culture positive. Positive elk and deer were more likely to be found through blood testing, opportunistic surveillance, and culling compared to hunting. No non-lesioned, culture-positive elk were detected in this study compared to previous studies in red deer.

Molecular detection of Babesia bovis and Babesia bigemina in white-tailed deer ( Odocoileus virginianus) from Tom Green County in central Texas

Serologic and molecular evidence suggest that white-tailed deer in South Texas and North Mexico carry the agents of bovine babesiosis, Babesia bovis and Babesia bigemina. To determine if white-tailed deer in central Texas, which is outside the known occurrence of the vector tick at this time, harbor these parasites, blood samples from free-ranging and captive white-tailed deer ( Odocoileus virginianus) in Tom Green County were tested by polymerase chain reaction (PCR) assays for B. bovis and B. bigemina 18S rDNA. Of the 25 samples tested, three (12%) were positive by nested PCR for B. bovis. This identity was confirmed by sequence analysis of the cloned 18S rDNA PCR product. Further confirmation was made by sequence analysis of the rRNA internal transcribed spacer (ITS) 1, 5.8S rRNA gene, and ITS 2 genomic region in two (representing samples from two different ranches) of the B. bovis positive samples. Three samples were positive by B. bigemina nested PCR, but sequencing of the cloned products confirmed only one animal positive for B. bigemina; Theileria spp. DNA was amplified from the other two animal samples. In addition to Theileria spp., two genotypically unique Babesia species sequences were identified among the cloned sequences produced by the B. bigemina primers in one sample. Phylogenetic analysis showed no separation of the deer B. bovis or B. bigemina 18S rDNA, or deer B. bovis ITS region sequences from those of bovine origin. Clarification of the possible role of white-tailed deer as reservoir hosts in maintaining these important pathogens of cattle is critical to understanding whether or not deer contribute to the epidemiology of bovine babesiosis.

Antimicrobial Susceptibility Testing ofMycobacterium bovisIsolates from Michigan White-Tailed Deer during the 2009 Hunting Season

Michigan has had an ongoing outbreak of endemic Mycobacterium bovis which has been recognized within and sustained by its free-ranging white-tailed deer population since 1994. Worldwide, organisms within the Mycobacterium tuberculosis complex have exhibited the ability to develop resistance to antimicrobial agents, resulting in both the multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of human tuberculosis. Michigan's Bovine Tuberculosis Working Group has conducted active antimicrobial susceptibility testing on wildlife isolates of the endemic M. bovis organism at five-year intervals to detect any emerging drug resistance patterns. The results of 33 white-tailed deer origin isolates collected from the 2009 hunting season are reported here. There continues to be no evidence of any drug resistance except for pyrazinamide resistance. These results are likely due to the lack of antibacterial treatment applied to either wildlife or domestic animals which would provide selection pressure for the development of drug resistance.

Persistence of Mycobacterium bovis Bacillus Calmette‐Guérin in White‐Tailed Deer (Odocoileus Virginianus) after Oral or Parenteral Vaccination

Mycobacterium bovis is the cause of tuberculosis in cattle and a serious zoonotic pathogen, most commonly contracted through consumption of unpasteurized dairy products. To control this zoonosis, many countries have developed bovine tuberculosis eradication programmes. Although relatively successful, efforts are hindered in many regions by spillover from wildlife reservoirs of M. bovis to cattle. Such is the case in the United States where spillover of M. bovis from free-ranging white-tailed deer to cattle occurs. One approach to control such inter-species transmission is vaccination of wildlife. The live, attenuated human vaccine M. bovis Bacillus Calmette-Guérin (BCG) has been shown to reduce disease severity in white-tailed deer; however, vaccine persistence within tissues has also been noted. Consumption of venison containing BCG by hunters may present a public health concern as BCG exposure, although unlikely to cause disease, could cause false positive tuberculin skin test results. To examine BCG persistence further, 42 white-tailed deer were vaccinated orally or subcutaneously (SC) with BCG Danish. Three deer from each group were killed and examined at periods ranging from 2 weeks to 11 months after vaccination. BCG was recovered from orally vaccinated deer as late as 3 months after vaccination, while BCG persisted in SC vaccinated deer for as long as 9 months. At no time was BCG isolated from meat; however, prolonged persistence was seen in lymphoid organs. Although vaccine persistence was noted, especially in SC vaccinated deer, the distribution of culture-positive tissues makes human exposure through consumption unlikely.

Plasma gossypol dynamics in white-tailed deer: Implications for whole cottonseed as a supplemental feed

Whole cottonseed (WCS) is a potential supplemental feed for white-tailed deer ( Odocoileus virginianus) in rangeland conditions because of its high digestible energy and protein content, moderate fiber content, and resistance to degradation in moist conditions. WCS also contains the polyphenolic secondary metabolite gossypol, which reduces palatability to non-target monogastric species but may be of concern for deer nutrition. Plasma gossypol stabilization when fed a constant dry matter intake, plasma gossypol depletion after WCS was removed from the diet, and the relationship between WCS consumption and plasma gossypol concentration was studied in 10 mature male ( N = 5) and female ( N = 5) captive white-tailed deer. Consumption of WCS by 73 free-ranging white-tailed deer (59 males, 14 females) was estimated using results of the captive study. Plasma gossypol concentrations declined exponentially and averaged 0.74 μg/mL 35 days after WCS was removed from the diet. Plasma gossypol concentration was linearly related to WCS consumption ( P < 0.001), with females having 0.35 μg/mL greater ( P = 0.04) plasma gossypol than males for a given rate of dry matter consumption. All female and 93% of male white-tailed deer captured in WCS supplemented pastures had detectable plasma gossypol. Female averaged 1.88 μg/mL of plasma gossypol and males averaged 4.84 μg/mL of plasma gossypol. Based on the captive deer data, these plasma values suggest an average WCS consumption of ∼2.6 g/kg BW/day for female free-ranging deer and ∼5.6 g/kg BW/day for male free-ranging deer. Inferentially, a large proportion of free-ranging white-tailed deer in rangeland conditions will consume WCS, with females consuming 125 g WCS/day and males consuming 428 g WCS/day. That plasma gossypol levels decrease rapidly after cottonseed is removed from the diet suggests that the long withdrawal periods often used prior to breeding season may not be needed. However, although 93% of gossypol was eliminated from the animals after a five-week withdrawal period, a small amount of gossypol can still be detected. While our preliminary data on these animals suggests that these levels are not detriment to animal health or reproduction, ranch managers may want to take a conservative approach to the feeding of WCS until these questions are answered.

CWD After “the Fire”: Six Reasons Why Hunters Resisted Wisconsin's Eradication Effort

Eight years after undertaking an unprecedented attempt to eradicate chronic wasting disease (CWD) from its free-ranging white-tailed deer (Odocoileus virginianus) population, Wisconsin wildlife managers are rethinking their strategies in the face of public opposition to their efforts. This article draws on a dozen surveys of hunters and landowners to identify six psychological bases that created deer hunter opposition to the Wisconsin plan. These include opposition to the population goal, conflicts with traditions, conflicts with consumption norms, the uncertainty of the plan's efficacy, and perceived lack of credibility in the agency. We argue that these six clusters of attitudinal beliefs made it unlikely that hunter support could have been cultivated regardless of the scope or pace of the CWD eradication effort. Our findings call into question the use of recreational hunting as a viable tool for bringing about severe deer population reductions for disease management.

Molecular and serologic evidence for Babesia bovis-like parasites in white-tailed deer ( Odocoileus virginianus) in south Texas

The current study was undertaken to determine if white-tailed deer in south Texas harbor Babesia bovis, a causative agent of bovine babesiosis. Blood samples from free-ranging white-tailed deer ( Odocoileus virginianus) on two ranches in LaSalle and Webb Counties were screened for B. bovis and other hemoparasites by the polymerase chain reaction (PCR) to detect the piroplasm 18S rDNA. Serology was conducted on selected samples to detect antibody activity to B. bovis by the immunofluorescent antibody test (IFAT). PCR revealed that 16% of the LaSalle County samples and 4% of the Webb County samples were positive for B. bovis. Five of the LaSalle County and the two Webb County B. bovis 18S rDNA amplicons were cloned and sequenced. The resulting clones shared 99% identity to B. bovis 18S rRNA gene sequences derived from cattle isolates. Weak seroreactivity to B. bovis was shown by the IFAT. The samples were also screened for additional hemoparasites of deer including Theileria cervi, Babesia odocoilei and other Babesia spp. A genotypically unique Theileria sp. was found, along with T. cervi and B. odocoilei. The finding of putative B. bovis in white-tailed deer necessitates further study to determine if deer may act as a transient host or even a reservoir of infection for B. bovis pathogenic to cattle.

HEPATIC MINERAL VALUES OF WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS) FROM VIRGINIA

There is a lack of information on mineral requirements of free-ranging white-tailed deer (Odocoileus virginianus). In addition, mineral deficiencies or excesses may play a role in the development of parasitism/malnutrition syndrome. We measured hepatic mineral values in apparently healthy white-tailed deer from two sites in Virginia, USA, as well as in deer with presumptive parasitism/malnutrition syndrome during 2005-2007. Deer with presumptive parasitism/malnutrition syndrome that were displaying signs of emaciation and chronic diarrhea had significantly higher mean hepatic levels of magnesium (Mg) and zinc (Zn) compared with healthy deer. Healthy deer in our study from northern Virginia, USA (i.e., Fairfax, Fauquier, Loudoun, and Prince William counties) had significantly lower mean hepatic selenium (Se) levels compared with deer from Nottoway County, Virginia, USA, which is 200 km distant. Healthy deer from northern Virginia, USA, also had significantly lower mean hepatic cobalt (Co), copper (Cu), and molybdenum (Mo) levels. Adult deer had significantly higher mean levels of hepatic iron (Fe) compared with fawns. In addition, male deer had significantly higher mean hepatic Co levels compared with female deer. The significantly higher mean (+/-SD) level of Zn in sick deer from northern Virginia, USA (78.7+/-54.9 microg/g versus 35.8+/-7.4 microg/g in healthy deer) is potentially clinically significant, although no signs consistent with Zn poisoning were observed. All deer in our study from northern Virginia, USA, had marginal or deficient levels of Cu (mean+/-SD=27.4+/-18.3 microg/g) and Se (mean=0.08+/-0.03 microg/g), which may be predisposing this population to the development of parasitism/malnutrition syndrome.

Investigations on Deer to Deer and Deer to Cattle Transmission of the Vaccine Mycobacterium bovis Bacillus Calmette-Guérin (BCG)

Mycobacterium bovis is the causative agent of tuberculosis in animals and can cause tuberculosis in humans clinically indistinguishable from that caused by Mycobacterium tuberculosis. Efforts to eradicate bovine tuberculosis have significantly decreased prevalence in developed countries. However, some countries have found it impossible to eradicate bovine tuberculosis due to the presence of a wildlife reservoir of M. bovis. In Michigan, USA there exists a reservoir of M. bovis in free-ranging white-tailed deer. Vaccination with M. bovis BCG is one approach to controlling tuberculosis in wildlife. Nevertheless, use of a live vaccine generates concerns about exposure risk to non-target species, including domestic livestock. Unintentional exposure of cattle to BCG may result in increased numbers of false positive tuberculin skin test reactions. Twenty-nine white-tailed deer received 1 SC dose of 107 colony-forming units of M. bovis BCG Danish 1331 (n=19) or no vaccination (n=10). Vaccinated and non-vaccinated deer were comingled with opportunity for direct and indirect contact. Twelve unvaccinated Holstein calves were housed in a separate paddock with no means of direct contact with deer; however, indirect contact through the sharing of feed and water was permitted. After 180 days, 11 out of 15 vaccinated deer and 4 out of 8 non-vaccinated deer were classified as reactors using the tuberculin skin test. All 12 calves were categorized as non-reactors, by both the tuberculin skin test and BOVIGAM™ assay. Vaccination of free-ranging white-tailed deer with BCG Danish is unlikely to have a deleterious effect on tuberculosis surveillance measures in cattle.

Aggressive Defensive Behavior by Free-Ranging White-Tailed Deer: Fig. 1

Maternal investment plays a critical role in neonate survival, and adults can improve survival of offspring by defending them against predators. However, limited information exists documenting ungulate aggression toward humans in defense of neonates. During captures of neonates in spring 2007 and 2008 in north-central South Dakota, we documented 24 aggressive encounters by adult female and yearling male and female white-tailed deer (Odocoileus virginianus) defending neonates. Eleven (45.8%) aggressive encounters included yearlings accompanying adult females. Mean ages and weights of neonates that were aggressively defended were greater (P < 0.0001) than ages and weights of those that were not; adults began protecting neonates at approximately 4 days of age. Male fawns were more likely (P = 0.013) to be defended than female fawns. Examination of our data suggests that sex- and age-biased maternal defensive behavior exists in white-tailed deer, and that deer biased maternal investment toward older, male neonates.

Genetic susceptibility to chronic wasting disease in free-ranging white-tailed deer: Complement component C1q and Prnp polymorphisms

The genetic basis of susceptibility to chronic wasting disease (CWD) in free-ranging cervids is of great interest. Association studies of disease susceptibility in free-ranging populations, however, face considerable challenges including: the need for large sample sizes when disease is rare, animals of unknown pedigree create a risk of spurious results due to population admixture, and the inability to control disease exposure or dose. We used an innovative matched case–control design and conditional logistic regression to evaluate associations between polymorphisms of complement C1q and prion protein (Prnp) genes and CWD infection in white-tailed deer from the CWD endemic area in south-central Wisconsin. To reduce problems due to admixture or disease-risk confounding, we used neutral genetic (microsatellite) data to identify closely related CWD-positive ( n = 68) and CWD-negative ( n = 91) female deer to serve as matched cases and controls. Cases and controls were also matched on factors (sex, location, age) previously demonstrated to affect CWD infection risk. For Prnp, deer with at least one Serine (S) at amino acid 96 were significantly less likely to be CWD-positive relative to deer homozygous for Glycine (G). This is the first characterization of genes associated with the complement system in white-tailed deer. No tests for association between any C1q polymorphism and CWD infection were significant at p < 0.05. After controlling for Prnp, we found weak support for an elevated risk of CWD infection in deer with at least one Glycine (G) at amino acid 56 of the C1qC gene. While we documented numerous amino acid polymorphisms in C1q genes none appear to be strongly associated with CWD susceptibility.

Epizootiology of Babesia bovis and Babesia bigemina in Free-ranging White-tailed Deer in Northeastern México

Species of Rhipicephalus (Boophilus) ticks are the vectors of babesiosis (cattle fever tick), which are distributed worldwide. White-tailed deer (Odocoileus virginianus) are important secondary hosts for the cattle fever ticks, Rhipicephalus (B.) annulatus and Rhipicephalus (B.) microplus. White-tailed deer are capable of sustaining Boophilus spp. tick populations in the presence or absence of cattle. The objectives of this study were to determine the frequency of Babesia bovis and Babesia bigemina and the prevalence of antibodies to them and identify possible risk factors for bovine babesiosis in white-tailed deer in 3 northeastern states of México. Whole blood and serum samples (n = 457) were collected from white-tailed deer in the states of Coahuila, Nuevo Leon, and Tamaulipas during the spring of 2004. Samples were tested for B. bovis and B. bigemina by nested polymerase chain reaction (n-PCR) (the primers for B. bovis identified the gene Rap-1 and B. bigemina were specific primers) and by an indirect immunofluorescence antibody test (IFAT). A questionnaire was given to each ranch to obtain information about management practices. Logistic regression methods were used to test the association between management factors and the dependent variable of positive n-PCR or IFAT. Nineteen (4.2%) samples were positive to B. bigemina and 6 (1.7%) were positive to B. bovis by n-PCR. Serological testing showed 59.9% (n = 274) of deer sampled were positive to B. bovis and 5.4% (n = 25) were positive to B. bigemina antibodies. The logistic model varied with different dependent variables. With positive n-PCR and B. bigemina as the dependent variable, 3 factors were associated: habitat (presence of brush and exotic grasses; odds ratio (OR), 3.3; 95% confidence interval (CI), 1.3-8.5), grazing system (continuous grazing OR 4.0; CI, 1.3-12.2), and tick treatment frequency (3-4 mo; OR 7.0, CI 1.4-34.3; 5-6 mo; OR, 11.0; CI, 1.9-62.7; > 6 mo; OR, 4.6; CI, 0.9-23.3). These findings suggest that white-tailed deer may act as a reservoir for the 2 bovine Babesia spp. and that white-tailed deer may be important in the epidemiology of babesiosis. However, evidence is not available to support whether white-tailed deer are, or are not, likely to be a host that could complete the transmission cycle of Babesia spp. These results suggest that additional research is needed to demonstrate the importance of white-tailed deer as a Babesia spp. infection source for ticks.

Serum 25-hydroxyvitamin D Concentrations in Captive and Free-ranging, White-tailed Deer (Odocoileus virginianus)

Serum concentrations of 25-hydroxyvitamin D [25(OH)D] were determined for free-ranging and captive white-tailed deer (WTD). Effects of gender, season, and age on 25(OH)D concentrations were determined as well as comparisons to concentrations in serum from captive reindeer and elk. Seasonal variations in 25(OH)D concentrations were detected for both captive and free-ranging WTD with greatest concentrations detected in August/September (approximately 25 ng/mL) and lowest concentrations in February (approximately 5 - 10 ng/mL). Free-ranging WTD < 1 year of age had lower 25(OH)D concentrations (approximately 6 ng/mL) than did free-ranging WTD > 1 year of age (approximately12 ng/mL). For captive WTD fawns, 25(OH)D concentrations increased from 1 to 9 days of age (exceeding 100 ng/mL) and then steadily declined to approximately 10 ng/mL by 3 months of age. In general, differences in 25(OH)D concentrations based on gender were not detected. 25(OH)D concentrations in captive WTD did not differ from that of captive reindeer; yet, 25(OH)D concentrations were lower in WTD than in captive elk. Additional research is necessary to determine if low serum 25(OH)D concentrations during the winter or pre-weaning period are associated with increased rates of infectious and metabolic disease.