The potential for transmission of BCG from orally vaccinated white-tailed deer (Odocoileus virginianus) to cattle (Bos taurus) through a contaminated environment: experimental findings.

White-tailed deer (Odocoileus virginianus) experimentally infected with a virulent strain of Mycobacterium bovis have been shown to transmit the bacterium to other deer and cattle (Bos taurus) by sharing of pen waste and feed. The risk of transmission of M. bovis bacille Calmette-Guerin (BCG) vaccine from orally vaccinated white-tailed deer to other deer and cattle, however, is not well understood. In order to evaluate this risk, we orally vaccinated 14 white-tailed deer with 1×10(9) colony forming units BCG in lipid-formulated baits and housed them with nine non-vaccinated deer. Each day we exposed the same seven naïve cattle to pen space utilized by the deer to look for transmission between the two species. Before vaccination and every 60 days until the end of the study, we performed tuberculin skin testing on deer and cattle, as well as interferon-gamma testing in cattle, to detect cellular immune response to BCG exposure. At approximately 27 weeks all cattle and deer were euthanized and necropsied. None of the cattle converted on either caudal fold, comparative cervical tests, or interferon-gamma assay. None of the cattle were culture positive for BCG. Although there was immunological evidence that BCG transmission occurred from deer to deer, we were unable to detect immunological or microbiological evidence of transmission to cattle. This study suggests that the risk is likely to be low that BCG-vaccinated white-tailed deer would cause domestic cattle to react to the tuberculin skin test or interferon-gamma test through exposure to a BCG-contaminated environment

Intranasal Inoculation of White-Tailed Deer (\u3ci\u3eOdocoileus virginianus\u3c/i\u3e) with Lyophilized Chronic Wasting Disease Prion Particulate Complexed to Montmorillonite Clay

Chronic wasting disease (CWD), the only known prion disease endemic in wildlife, is a persistent problem in both wild and captive North American cervid populations. This disease continues to spread and cases are found in new areas each year. Indirect transmission can occur via the environment and is thought to occur by the oral and/or intranasal route. Oral transmission has been experimentally demonstrated and although intranasal transmission has been postulated, it has not been tested in a natural host until recently. Prions have been shown to adsorb strongly to clay particles and upon oral inoculation the prion/clay combination exhibits increased infectivity in rodent models. Deer and elk undoubtedly and chronically inhale dust particles routinely while living in the landscape while foraging and rutting. We therefore hypothesized that dust represents a viable vehicle for intranasal CWD prion exposure. To test this hypothesis, CWD-positive brain homogenate was mixed with montmorillonite clay (Mte), lyophilized, pulverized and inoculated intranasally into white-tailed deer once a week for 6 weeks. Deer were euthanized at 95, 105, 120 and 175 days post final inoculation and tissues examined for CWD-associated prion proteins by immunohistochemistry. Our results demonstrate that CWD can be efficiently transmitted utilizing Mte particles as a prion carrier and intranasal exposure

Comparative cervical test (CCT) results in individual deer at each time point and outcomes of tissue culture at necropsy.

*<p>N = negative; S = suspect; R = reactor.</p

Numbers of CCT reactor white-tailed deer at four time points.

<p>Numbers of vaccinated and non-vaccinated white-tailed deer of total tested that were comparative cervical skin test reactors as measured at four time points.</p

Experimental infection of white-tailed deer (\u3ci\u3eOdocoileus virginianus\u3c/i\u3e) with Northern European bluetongue virus serotype 8

Bluetongue (BT) is an insect-transmitted, economically important disease of domestic and wild ruminants. Although only five of the 26 reported bluetongue virus (BTV) serotypes are considered endemic to the USA, 10 exotic serotypes have been isolated primarily in the southeastern region of the country since 1999. For an exotic BTV serotype to become endemic there must be susceptible animal species and competent vectors. In the USA, sheep and white-tailed deer (WTD) are the primary sentinel livestock and wildlife species, respectively. In 2006, BTV-8 was introduced into Northern Europe and subsequently overwintered, causing unprecedented livestock disease and mortality during the 2006– 2007 vector seasons. To assess the risk of the European strain of BTV-8 to North American WTD, and understand the role they could play after a similar introduction, eight bluetongue-seronegative WTD were inoculated with BTV-8. Body temperatures and clinical signs were recorded daily. Blood samples were analyzed for BTV RNA with quantitative real time reverse transcriptase polymerase chain reaction (qRT-PCR), serum analyzed for BTV antibodies by cELISA, and tissues taken for histopathology and qRT-PCR. All eight deer became infected and developed moderate to severe clinical disease from days 8 to 15. Peak viremia was from day 7 to 10 with detectable titers through the end of the study (28 days) in most deer. Serum antibody was detected by day 6, peaked by day 10 and continued through day 28. We conclude that North American WTD are highly susceptible to BTV-8 and would act as clinical disease sentinels and amplifying hosts during an outbreak

Intranasal inoculation of white-tailed deer (Odocoileus virginianus) with lyophilized chronic wasting disease prion particulate complexed to montmorillonite clay.

Chronic wasting disease (CWD), the only known prion disease endemic in wildlife, is a persistent problem in both wild and captive North American cervid populations. This disease continues to spread and cases are found in new areas each year. Indirect transmission can occur via the environment and is thought to occur by the oral and/or intranasal route. Oral transmission has been experimentally demonstrated and although intranasal transmission has been postulated, it has not been tested in a natural host until recently. Prions have been shown to adsorb strongly to clay particles and upon oral inoculation the prion/clay combination exhibits increased infectivity in rodent models. Deer and elk undoubtedly and chronically inhale dust particles routinely while living in the landscape while foraging and rutting. We therefore hypothesized that dust represents a viable vehicle for intranasal CWD prion exposure. To test this hypothesis, CWD-positive brain homogenate was mixed with montmorillonite clay (Mte), lyophilized, pulverized and inoculated intranasally into white-tailed deer once a week for 6 weeks. Deer were euthanized at 95, 105, 120 and 175 days post final inoculation and tissues examined for CWD-associated prion proteins by immunohistochemistry. Our results demonstrate that CWD can be efficiently transmitted utilizing Mte particles as a prion carrier and intranasal exposure

Tracking lyophilized prion inocula in the nasal cavity of deer.

<p>Highly enriched, fluorescently labeled prions were mixed with Mte, lyophilized, pulverized and puffed into the nasal cavity. (A) After 45 minutes, florescent prion aggregates (red) can be seen on (white arrowheads) and within the olfactory epithelium (OE) of the nasal turbinates. Tissue sections are counterstained with DiOC₁₈ fluorescent membrane dye (green) and the nuclear stain DAPI (blue). A small proportion of prions can be seen near serous cells of the Bowman's glands (BG) in the lamina propria. (B) By 60 min, significant amount of prions were found in the lamina propria, with some aggregates (arrowhead) associated with nerve fibers (NF) emanating from the OE. (C) We detected no red signal from negative control sections from mock-inoculated deer. (D–G) Higher magnification of a Bowman's gland stained with DAPI (D), DiOC₁₈ (E) and decorated with prions (F) that appear to localize on serous cells (G). NB, nerve bundle; scale bar, 20 µm.</p

Lymphoid Involvement at each of the 4 time points.

<p>No significant difference was detected in the number of affected follicles between the groups (ANOVA, <i>p = </i>0. 86).</p

Detection of CWD in lymphoid follicles.

<p>Between 1600 and 3069 lymphoid follicles from head LNs, tonsils, pre-scapular and femoral LNs, Peyer's patches, mesenteric LN, gut LNs and rectum were evaluated in each deer for the presence of CWD by IHC. Percentage of total follicles IHC-positive for CWD ranged between 0->70%, depending on genotype. (<b>*</b>Control mock-infected deer).</p

Expulsion of the lypholized CWD/Mte inoculum from a transfer pipette illustrating the ultrafine texture of the inoculum.

<p>Expulsion of the lypholized CWD/Mte inoculum from a transfer pipette illustrating the ultrafine texture of the inoculum.</p