Lesion development in white-tailed deer (Odocoileus virginianus) experimentally infected with Mycobacterium bovis

The recent discovery of tuberculosis in free-living white-tailed deer in northeastern Michigan underscores the need for increased understanding of the pathogenesis of tuberculosis in wildlife species. To investigate lesion development in white-tailed deer, 32 deer were experimentally infected by intratonsilar instillation of 300 colony-forming units of Mycobacterium bovis. Three deer each were euthanatized and examined at days 15, 28, 42, and 56 after inoculation, and five deer each were euthanatized and examined at days 89, 180, 262, and 328 after inoculation. Microscopic lesions first were seen in the medial retropharyngeal lymph node and lung 28 and 42 days after inoculation, respectively. Lung lesions were present in 12 (38%) of 32 deer, involving 23 lung lobes. Left caudal and right middle and caudal lobes were involved in 17 (74%) of the 23 affected lung lobes. Lesions in the medial retropharyngeal lymph node first appeared as granulomas composed of aggregates of macrophages and Langhans-type giant cells. Some early granulomas contained centrally located neutrophils. As granulomas developed, neutrophils were replaced with a central zone of caseous necrosis that first showed signs of mineralization 42 days after inoculation. Granulomas increased in size as the zone of caseous necrosis expanded. Peripheral fibrosis, first seen at 56 days after inoculation, progressed to only a thin fibrous capsule by 328 days after inoculation. By the termination of the study, the central necrotic core of the granuloma contained abundant liquefied necrotic material and grossly resembled an abscess. Although tuberculous lesions in white-tailed deer follow a developmental pattern similar to that in cattle, fibrosis is less pronounced and the advanced lesions may liquefy, a change seldom reported in cattle. An understanding of lesion development will aid in the identification of the spectrum of disease that may be seen in this important wildlife reservoir of tuberculosis.     

Comparison of postmortem techniques for the detection of Mycobacterium bovis in white-tailed deer (Odocoileus virginianus).

A retrospective study of various diagnostic postmortem techniques used in a 4-year surveillance program for detection of Mycobacterium bovis infection in wild white-tailed deer (Odocoileus virginianus) was conducted. The tests evaluated were routine histopathology, acid-fast staining, detection of acid-fast bacilli in culture, and an M. tuberculosis group-specific genetic probe applied to pure cultures. Each of these techniques were compared with a reference or "gold standard" of mycobacterial culture and identification. Histopathology, the most rapid form of testing for M. bovis infection in white-tailed deer samples, had a sensitivity of 98% and a specificity of 87%, resulting in a positive predictive value of 94%. The detection of acid-fast bacilli by staining was less sensitive than histopathology (90%), but its higher specificity (97%) resulted in a positive predictive value of 99%. The detection of acid-fast bacilli on culture was both highly specific (93%) and sensitive (100%). The group-specific genetic probe had the highest sensitivity and specificity and produced results in complete agreement with those of mycobacterial culture, suggesting that this technique could be used as the new "gold standard" for this particular wildlife tuberculosis surveillance program.     

Spatial analysis of Mycobacterium bovis infection in white-tailed deer (Odocoileus virginianus) in Michigan, USA

The wild white-tailed deer (Odocoileus virginianus) population in Michigan, USA, has endemic Mycobacterium bovis. We determined whether there were spatial clusters of retrospective TB cases in white-tailed deer in northeastern Michigan and identified specific factors associated with the spatial clusters. Data from hunter-harvested deer (age, gender, TB status, and geographic section) were collected by the Michigan Department of Natural Resources (MDNR) during TB surveillance from 1995 to 2002. Land cover (vegetation, land-use) and land type (soil types and drainage characteristics, landforms) described potential deer habitats. Specific locations of large-scale supplemental feeding sites were collected from the MDNR aerial surveillance program from 1997 to 2002. Analyses were conducted using principal components derived from environmental data (and other risk factors) on spatial clusters of disease (identified by the spatial scan statistic). Spatial effects were incorporated into the multivariable analyses by using a neighborhood approach. A total of 420 deer with M. bovis infection were identified from 1995 to 2002, out of 39,451 harvested deer from 3216 TRS units, and spatial clusters of cases were identified. A total of seven principal components of environmental data were generated. Clusters were associated with the presence of large expanses of deciduous forests on moraine ridges separated by low areas of forested wetlands, and the presence of many small lakes. Factors that promoted congregation of deer for extended periods of time (natural cover, access to water, and less human contact) appeared to be associated with increased odds of TB positivity. This suggests that there are specific areas where interventions can be implemented to reduce congregation of animals and disrupt the cycle of infection transmission.     

Isolation of Neospora caninum from naturally infected white-tailed deer (Odocoileus virginianus)

Attempts were made to isolate Neospora caninum from naturally infected white-tailed deer (Odocoileus virginianus). A total of 110 deer killed during the 2003 hunting season in Virginia region were used for the isolation of N. caninum. Of these, brains from 28 deer that had NAT titer of 1:200 were inoculated into interferon-gamma gene knock out (KO) mice. N. caninum was isolated from the tissues of three deer and all three isolates were mildly virulent to KO mice. Only one of the isolates could be adapted to in vitro growth. Protozoa in the tissues of KO mice reacted with N. caninum-specific polyclonal antibodies and N. caninum DNA was demonstrated in infected tissues by PCR assays; sequences of portions of the ITS-1 and gene 5 loci were identical to those in the public database. This is the first record of in vitro isolation of N. caninum from white-tailed deer and lends credence to the white-tailed deer as an intermediate host for this parasite.     

Hepatocellular adenocarcinoma in a white-tailed deer (Odocoileus virginianus).

A white-tailed deer (Odocoileus virginianus), shot during the 1978-79 New Jersey hunting season, was presented with an enlarged, multinodular liver and numerous skin growths. The skin lesions were found to be fibromas and the liver tumor was identified as a hepatocellular adenocarcinoma, a rare neoplasm, not only in deer but all wild animals.     

Tuberculin skin testing in white-tailed deer (Odocoileus virginianus).

The comparative cervical skin test for antemortem diagnosis of tuberculosis was done 169 times on 116 different white-tailed deer of known Mycobacterium bovis infection status. The sensitivity and specificity were 97 and 81%, respectively. The magnitude of change in skin thickness at test sites was not significantly influenced by dosage of inoculum, dissemination of the disease process, or repeated skin testing. However, the magnitude of change in skin thickness was significantly greater in deer infected for less than 109 days than in deer infected for more than 109 days. As used in the present study, the comparative cervical skin test is a sensitive method of antemortem diagnosis of M. bovis infection in white-tailed deer.     

Congenital polycystic kidney in a white-tailed deer (Odocoileus virginianus).

Polycystic kidney and liver disease was seen in a stillborn white-tailed deer (Odocoileus virginianus) fawn. Bilaterally enlarged kidneys were characterized by severe dilatation of all renal tubules. Glomeruli were sparse, small, and located within a dilated Bowman's capsule. The liver was characterized by marked periportal fibrosis, biliary hyperplasia, and bile duct ectasia with dilated ducts containing inspissated bile. The presentation and morphology of this case are most similar to autosomal recessive polycystic disease in humans.     

Estradiol and progesterone metabolite concentration in white-tailed deer (Odocoileus virginianus) feces.

Assays of reproductive hormone metabolites require validation in each animal species. For validation of methodology in white-tailed deer (Odocoileus virginianus), fecal samples were collected from females that had been injected by blowgun with estradiol, progesterone, or a control substance. Analysis by radioimmunoassay revealed that estradiol and pregnanediol were more abundant fecal metabolites of estrogens and progestins than were estrone or progesterone. Peak excretion rates of estradiol and pregnanediol occurred within 12 and 24 hr of injection, respectively. Ovulation time was estimated by measuring the frequency of occurrence of eight behavior patterns, including copulation. Profiles were compiled for three deer over the course of estrus and early pregnancy for estradiol, estrone, progesterone, and pregnanediol using radioimmunoassay. Pregnanediol was excreted at concentrations about 1,000 times higher than those of the other three fecal steroid metabolites, and pregnanediol differed in concentration during estrus, the luteal phase, and early pregnancy. Consequently, a simpler enzyme immunoassay was adapted and used to measure pregnanediol levels over the course of estrus and early pregnancy for seven deer. Measurement of fecal pregnanediol is useful for monitoring reproductive events in female white-tailed deer.     

Susceptibility of male white-tailed deer (Odocoileus virginianus) to Brucella ovis infection

Infection with Brucella ovis was established by conjunctival instillation in 8 male white-tailed deer (Odocoileus virginianus). Infection was transient in young bucks, but persisted in bucks that were mature when inoculated. The deer were euthanatized and necropsied at various intervals after inoculation. Brucella ovis was recovered from a mature buck at necropsy on postinoculation day 429. Four deer had gross lesions and histopathologic changes of the epididymides. A mature noninfected buck confined for 7 months with an infected buck acquired infection and developed epididymal lesions.     

Choroid plexitis in white-tailed deer (Odocoileus virginianus) in southern New York State

Brains, spinal cords, nerve roots, nerves and muscle tissues were removed from deer in southern New York State and examined for histologic evidence of infection by the causative agent of Lyme disease, Borrelia burgdorferi. There was no histologic evidence of this infection and only four of 26 deer had serologic evidence of past infection despite the fact that all were parasitized by the tick vector, Ixodes dammini. Of these ticks, 21% were carrying B. burgdorferi. In contrast, most of the deer had choroid plexitis. All but one of 48 deer tested were infected with Trypanosoma cervi, 20 of 24 deer had sarcocystis in skeletal muscles and two had dural lesions probably due to the nematode Pneumostrongylus tenuis. The causal relationship between choroid plexitis and trypanosomiasis is discussed.     

Surgical technique for tubal ligation in white-tailed deer (Odocoileus virginianus).

Surgical tubal ligation was used to sterilize urban free-ranging white-tailed deer (Odocoileus virginianus) as a methodology of a larger study investigating the influences of intact, sterile females on population dynamics and behavior. Deer were either trapped in clover traps (n = 55) and induced with an i.m. injection of xylazine and tiletamine/zolazepam or induced by a similar protocol by dart (n = 12), then intubated and maintained on isoflurane in oxygen. Over 3 yr, individual female deer (n = 103) were captured in Highland Park, Illinois, with a subset of females sterilized using tubal ligation by ventral laparotomy (n = 63). Other sterilization procedures included tubal transection by ventral (n = 1) or right lateral (n = 2) laparoscopy and ovariohysterectomy by ventral laparotomy (n = 1). One mortality (1/ 67, 1.5%) of a doe with an advanced pregnancy was attributed to a lengthy right lateral laparoscopic surgery that was converted to a right lateral laparotomy. The initial surgical modality of laparoscopy was altered in favor of a ventral laparotomy for simplification of the project and improved surgical access in late-term gravid does. Laparotomy techniques included oviductal ligation and transection (n = 14), application of an oviductal mechanical clip (n = 9), ligation and partial salpingectomy (n = 40), and ovariohysterectomy (n = 1). As of 2 yr poststerilization, no surgical does were observed with fawns, indicating that these procedures provide sterilization with low mortality in urban white-tailed deer.     

Pharmacokinetics of imidocarb dipropionate in white-tailed deer (Odocoileus virginianus) after single intramuscular administration

This study was designed to investigate the pharmacokinetics of imidocarb, a carbanilide derivative, in white-tailed deer (Odocoileus virginianus). The pharmacokinetic properties of a single intramuscular (IM) dose of imidocarb were determined in 10 deer. A single IM injection of 3.0 mg/kg imidocarb dipropionate was administered, and blood samples were collected prior to, and up to 48 hr after imidocarb administration. Plasma imidocarb concentrations were determined by high-performance liquid chromatography with ultraviolet detection. The disposition of plasma imidocarb was best characterized by a two-compartment open model. The mean ± SE maximal imidocarb concentration in deer was 880.78 ± 81.12 ng/ml at 38.63 ± 5.30 min postinjection. The distribution phase had a half-life (t_1/2α) of 25.90 ± 10.21 min, and plasma imidocarb concentration declined with a terminal elimination half-life (t_1/2β) of 464.06 ± 104.08 min (7.73 ± 1.73 hr). Apparent volume of distribution based on the terminal phase (V_Z/F) was 9.20 ± 2.70 L/kg, and apparent total body clearance (Cl/F) was 15.97 ± 1.28 ml min⁻¹ kg⁻¹.     

Molecular and serological prevalence of Babesia bovis and Babesia bigemina in cattle from central region of Syria

A total of 207 bovine blood samples were collected from clinically healthy cattle bred in central region of Syria and examined by Giemsa-stained blood smears, nested PCR, ELISA, and IFAT to determine the molecular and serological prevalence of Babesia bovis and B. bigemina. All samples were negative to Babesia spp. by microscopic examination of blood smears. On the other hand, the overall prevalence of B. bovis and B. bigemina was 9.18% and 15.46% by nPCR, 15.46% and 18.84% by ELISA, and 18.36% and 21.74% by IFAT, respectively. Mixed infections were detected in a total of 5 samples (2.4%) by nPCR, 16 (7.73%) by ELISA and 27 (13.04%) by IFAT. Statistically significant differences in the prevalence of the two infections were observed on the basis of age and location. These data provide valuable information regarding the occurrence and epidemiology of B. bovis and B. bigemina infections in Syrian cattle, which can be employed in developing rational strategies for disease control and management.     

Fatal pulmonary edema in white-tailed deer (Odocoileus virginianus) associated with adenovirus infection.

Sporadic sudden deaths in adult white-tailed deer occurred from November 1997 through August 1998 on an Iowa game farm. Three of the 4 deer necropsied had severe pulmonary edema, widespread mild lymphocytic vasculitis, and amphophilic intranuclear inclusion bodies in scattered endothelial cells in blood vessels in the lung and abdominal viscera. Immunohistochemistry with bovine adenovirus 5 antisera and transmission electron microscopy demonstrated adenoviral antigen and nucleocapsids, respectively, within endothelial cells. Adenovirus was isolated in cell culture from 1 of the affected deer. The isolate was neutralized by California black-tailed deer adenovirus antiserum. These findings indicate that adenovirus should be considered in the differential diagnosis of both black-tailed and white-tailed deer with pulmonary edema and/or hemorrhagic enteropathy.     

Isolation and characterization of epizootic hemorrhagic disease virus from white-tailed deer (Odocoileus virginianus) in eastern Washington.

A virus was isolated from the spleen of a white-tailed deer (Odocoileus virginianus) that had died during an epizootic in Washington state in 1967. Inoculation of a 10% spleen suspension from the deer caused hemorrhagic disease in normal white-tailed deer. Studies were conducted on the biological, physicochemical, and serologic properties of the Washington isolate. An in vitro assay system, utilizing a cultured primary of white-tailed deer fetal cells from an entire fetus, was employed for isolation and propagation of the virus. Cytopathic effect was characterized by focal development of rounded and clumped cells. Propagation was unsuccessful in suckling mice, BHK-21, and Vero cell cultures. The virus was resistant to treatment with ether, sodium deoxycholate, trypsin, oxytetracycline hydrochloride, and was sensitive to chloroform. Virus yield was not affected when infected cultures were treated with 5-iodo-2'-deoxyuridine, but dactinomycin (actinomycin D) treatment of infected cultures reduced virus yield. The virus was inactivated when heated at 70 C for 5 minutes or when exposed to pH 5 for 18 hours at 4 C. The virus was completely excluded from the filtrate by a 0.10- micronm (APD) membrane filter. Staining of infected cells with acridine orange indicated the presence of double-standard nucleic acid in the cytoplasm. Serum-neutralization tests with antiserums against the homologous virus and the New Jersey and Alberta strains of epizootic hemorrhagic disease virus resulted in neutralization of the Washington isolate. The Washington virus was not neutralized by bluetongue virus antiserum. Cells infected with the Washington isolate exhibited intracytoplasmic fluorescence by the indirect fluorescent antibody method with New Jersey and Alberta epizootic hemorrhagic disease antiserums but not with bluetongue antiserum.