The objective of this study was to determine whether post-vaccination antibody titers vary according to body weight in adult dogs. Antibody titers against canine parvovirus type 2 (CPV-2), canine distemper virus (CDV), and canine adenovirus type 1 (CAdV-1) were measured for 978 domestic adult dogs from 2 to 6 y of age. The dogs had been vaccinated approximately 12 mo earlier with a commercial combination vaccine. The dogs were divided into groups according to their weight. It was found that mean antibody titers in all weight groups were sufficient to prevent infection. Intergroup comparison, however, revealed that CPV-2 antibody titers were significantly higher in the Super Light (< 5 kg) group than in the Medium (10 to 19.9 kg) and Heavy (> 20 kg) groups and were also significantly higher in the Light (5 to 9.9 kg) group than in the Heavy group. Antibody titers against CDV were significantly higher in the Super Light, Light, and Medium groups than in the Heavy group. There were no significant differences among the groups for the CAdV-1 antibody titers.

Objective: To evaluate the efficacy of vaccination with the Leptospira interrogans serovar hardjo type hardjoprajitno component of a pentavalent Leptospira bacterin against a virulent experimental challenge with Leptospira borgpetersenii serovar hardjo type hardjo-bovis strain 203 in cattle. Animals: Fifty-five 6-month-old Holstein heifers. Procedures: Heifers that were negative for persistent infection with bovine viral diarrhea virus determined via immunohistochemical testing and negative for Leptospira interrogans serovar pomona, Leptospira interrogans serovar hardjo, Leptospira interrogans serovar grippotyphosa, Leptospira interrogans serovar bratislava, Leptospira interrogans serovar canicola, and Leptospira interrogans serovar icterohaemorrhagiae determined via microscopic agglutination assay were enrolled in the study. Two heifers were separated and used for the challenge passage. The remaining heifers were vaccinated twice with a commercial pentavalent bacterin or a sham vaccine 21 days apart and subsequently challenged with L borgpetersenii serovar hardjo type hardjo-bovis strain 203. Urinary shedding, antibody titers, and clinical signs of leptospirosis infection were recorded for 8 weeks after challenge. Results: Heifers that received the pentavalent bacterin did not shed the organism in urine after challenge and did not have renal colonization at necropsy. Heifers that were sham vaccinated shed the organism in urine and had renal colonization. Conclusions and Clinical Relevance: Results provided evidence that a pentavalent Leptospira vaccine containing L interrogans serovar hardjo type hardjoprajitno can provide protection against challenge with L borgpetersenii serovar hardjo type hardjo-bovis strain 203. It is important to demonstrate cross-protection that is vaccine specific against disease-causing strains of organisms that are prevalent under field conditions.

Objective: To assess the transmission of bovine viral diarrhea virus (BVDV) from experimentally infected white-tailed deer fawns to colostrum-deprived calves by use of a BVDV strain isolated from hunter-harvested white-tailed deer. Animals: 5 white-tailed deer (Odocoileus virginianus) fawns and 6 colostrum-deprived calves. Procedures: Fawns were inoculated intranasally with a noncytopathic BVDV-1a isolate (2 mL containing 10(6.7) TCID(50)/mL), and 2 days after inoculation, animals were commingled until the end of the study. Blood and serum samples were obtained on days −6, 0, 7, 14, and 21 after inoculation for reverse transcriptase PCR assay, virus neutralization, and BVDV-specific antibody ELISA. Nasal, oral, and rectal swab specimens were collected on days 0, 3, 7, 14, 17, and 21 for reverse transcriptase PCR testing. By 21 days after inoculation, all animals were euthanized and necropsied and tissues were collected for histologic evaluation, immunohistochemical analysis, and virus isolation. Results: All fawns became infected and shed the virus for up to 18 days as determined on the basis of reverse transcriptase PCR testing and virus isolation results. Evidence of BVDV infection as a result of cohabitation with acutely infected fawns was detected in 4 of the 6 calves by means of reverse transcriptase PCR testing and virus isolation. Conclusions and Clinical Relevance: On the basis of these findings, BVDV transmission from acutely infected fawns to colostrum-deprived calves appeared possible.

Porcine reproductive and respiratory syndrome (PRRS) is characterized by a delayed and defective adaptive immune response. The viral nonstructural protein 1 (NSP1) of the PRRS virus (PRRSV) is able to suppress the type I interferon (IFN) response in vitro. In this study, recombinant adenoviruses (rAds) expressing NSP1 (rAd-NSP1), glycoprotein 5 (GP5) (rAd-GP5), and the NSP1-GP5 fusion protein (rAd-NSP1-GP5) were constructed, and the effect of NSP1 on immune responses was investigated in pigs. Pigs inoculated with rAd-NSP1 or rAd-NSP1-GP5 had significantly lower levels of IFN-γ and higher levels of the immunosuppressive cytokine IL-10 than pigs inoculated with rAd-GP5, wild-type adenovirus, or cell culture medium alone. The antibody response to vaccination against classic swine fever virus (CSFV) was significantly decreased by inoculation of NSP1 7 d after CSFV vaccination in pigs. Thus, NSP1-mediated immune suppression may play an important role in PRRSV pathogenesis.

Objective: To describe the immunopathologic characteristics of superficial stromal immune-mediated keratitis (IMMK) immunopathologically by characterizing cellular infiltrate in affected corneas of horses. Animals: 10 client-owned horses with IMMK. Procedures: Immunohistochemical staining was performed on keratectomy samples with equine antibodies against the T-cell marker CD3 and B-cell marker CD79a (10 eyes) and the T-helper cytotoxic marker CD4 and T-cell cytotoxic marker CD8 (6 eyes). Percentage of positively stained cells was scored on a scale from 0 (no cells stained) to 4 (> 75% of cells stained). Equine IgG, IgM, and IgA antibodies were used to detect corneal immunoglobulin via direct immunofluorescence (10 eyes). Serum and aqueous humor (AH) samples from 3 horses with IMMK were used to detect circulating and intraocular IgG against corneal antigens via indirect immunofluorescence on unaffected equine cornea. Results: Percentage scores (scale, 0 to 4) of cells expressing CD3 (median, 2.35 [range, 0.2 to 3.7]; mean ± SD, 2.36 ± 1.08) were significantly greater than scores of cells expressing CD79a (median, 0.55 [range, 0 to 1.5]; mean, 0.69 ± 0.72). All samples stained positively for CD4- and CD8-expressing cells, with no significant difference in scoring. All samples stained positively for IgG, IgM, and IgA. No serum or AH samples collected from horses with IMMK reacted with unaffected equine cornea. Conclusions and Clinical Relevance: Pathogenesis of superficial stromal IMMK included cell-mediated inflammation governed by both cytotoxic and helper T cells. Local immunoglobulins were present in affected corneas; however, corneal-binding immunoglobulins were not detected in the serum or AH from horses with IMMK.

Objective: To determine whether vaccine virus can be detected by use of reverse transcriptase (RT)-PCR assays for pooled and individual skin samples obtained from cattle after vaccination with a commercially available modified-live bovine viral diarrhea virus (BVDV) vaccine. Animals: 12 BVDV-seropositive steer calves and 7 BVDV-seronegative (antibody titer < 1:4) heifers; all cattle were free of persistent infection with BVDV. Procedures: 2 experiments were conducted. Cattle were vaccinated on day 0 with a commercially available modified-live BVDV vaccine. Skin samples were collected on days 0, 3 to 14, 16, and 18 for virus detection by use of RT-PCR assay on individual and pooled samples. In addition, blood samples and nasal swab specimens were collected for virus isolation. Results: All cattle, regardless of serologic status, had negative results for BVDV as determined by use of RT-PCR assay of individual and pooled skin samples. Virus was detected via virus isolation in serum or the buffy coat in 5 of 7 heifers that were seronegative when vaccinated. Conclusions and Clinical Relevance: These findings indicated that it would be unlikely to detect BVDV vaccine virus in skin by use of RT-PCR assay of individual or pooled skin samples obtained from cattle after vaccination with a commercially available modified-live BVDV vaccine. Veterinarians and producers should be confident that positive test results for BVDV on skin samples would not likely be caused by the vaccination virus after administration of a modified-live virus vaccine.

Objective: To examine whether a zinc l-carnosine compound used for treatment of suspected gastric ulcers in dogs ameliorates acid-induced injury in canine gastric mucosa. Sample: Gastric mucosa from 6 healthy dogs. Procedures: Mucosa from the gastric antrum was harvested from 6 unadoptable shelter dogs immediately after euthanasia and mounted on Ussing chambers. The tissues were equilibrated for 30 minutes in neutral Ringer's solution prior to incubation with acidic Ringer's solution (HCl plus Ringer's solution [final pH, 1.5 to 2.5]), acidic Ringer's solution plus zinc l-carnosine compound, or zinc l-carnosine compound alone. Tissues were maintained for 180 minutes in Ussing chambers, during which permeability was assessed by measurement of transepithelial electrical resistance. After the 180-minute treatment period, tissues were removed from Ussing chambers and labeled with immunofluorescent anti–active caspase-3 antibody as an indicator of apoptosis. Results: Permeability of the gastric mucosa was significantly increased in a time-dependent manner by addition of HCl, whereas control tissues maintained viability for the study period. Change in permeability was detected within the first 15 minutes after acid application and progressed over the subsequent 150 minutes. The zinc l-carnosine compound had no significant effect on this increase in permeability. Apoptosis was evident in acid-treated tissues but not in control tissues. The zinc l-carnosine compound did not protect against development of apoptosis. Conclusions and Clinical Relevance: Addition of HCl caused a dose-dependent increase in gastric permeability over time and apparent induction of apoptosis as determined on the basis of immunofluorescence. However, there was no significant protective effect of a zinc l-carnosine compound. Nonetheless, results suggested the utility of this method for further studies of canine gastric injury.

This study investigated if parenteral administration of a prototype adjuvanted vaccine against porcine circovirus type 2 (PCV2) could override maternally derived antibodies and induce acquired immunity in young piglets. Piglets with high levels of maternal PCV2 antibodies at 1 wk of age were randomly grouped into vaccinates and controls on the basis of body weight and inoculated with the vaccine or a control preparation twice, with an interval of 3 wk. Both groups were challenged 3 wk after the booster vaccination and euthanized 3 wk after challenge. The pigs were evaluated for clinical disease, histologic lesions in sections of gastric and left inguinal lymph nodes stained with hematoxylin and eosin, and the amount of PCV2 antigen in the lymph nodes by immunohistochemical study. The PCV2 antibody titers were monitored by competitive enzyme-linked immunosorbent assay throughout the experiment. The vaccinates showed significantly less decline (P < 0.05) in PCV2 antibody titers after the booster vaccination. Clinical disease did not develop in any of the piglets. The vaccinates and controls did not differ in either histologic lesions or amount of PCV2 antigen in the lymph nodes. This study demonstrated some evidence of priming of young piglets in the presence of maternal antibodies. Further studies are recommended to determine the optimum concentration of PCV2 antigen and a suitable adjuvant for the vaccine to achieve the full potential of the strategy of inducing acquired immunity in young piglets that have maternally derived antibodies.

Objective: To determine the frequency of spontaneous canine herpesvirus-1 (CHV-1) reactivation and ocular viral shedding in latently infected dogs and the effect of topical ocular administration of cyclosporine. Animals: 8 mature Beagles with experimentally induced latent CHV-1 infection. Procedures: Following induction of primary ocular CHV-1 infection, the presence of reactivatable CHV-1 latency was confirmed by systemically administering prednisolone to the dogs. Dogs were then monitored for 36 weeks via clinical examination and conjunctival sample CHV-1 PCR assay performed at 4-day intervals and CHV-1 virus neutralization antibody assay performed at 2-week intervals. During weeks 16 to 32, dogs were administered 0.2% cyclosporine ointment in both eyes twice daily and blood cyclosporine concentrations were monitored. During weeks 33 to 36, the presence of reactivatable CHV-1 latency was reconfirmed via systemic administration of prednisolone. Results: Reactivation of latent CHV-1 was not detected via clinical examination or viral shedding during the initial 32 weeks, including before and during topical ocular administration of cyclosporine, and there were no significant differences in CHV-1 virus neutralization titer increases between the study periods. Blood cyclosporine concentrations were less than assay detection limits in all dogs on the sampling days. Systemic administration of corticosteroids repeatedly resulted in ocular disease and viral shedding. Conclusions and Clinical Relevance: Spontaneous CHV-1 reactivation did not occur frequently in latently infected mature dogs, and this was not altered by topical ocular administration of cyclosporine. This characteristic may be a factor contributing to the lower frequency of recurrent herpetic ocular disease in dogs relative to other host species and their associated alphaherpesviruses.