Objective-To determine whether cats exposed at a residence were infected with Mycobacterium bovis, whether the tuberculin skin test can identify cats infected with M bovis, and whether an ELISA could identify tuberculosis-infected cats. Animals-20 domestic cats exposed to a cat with laboratory-confirmed disseminated M bovis infection. Procedure-Cats were administered a tuberculin skin test and monitored for 72 hours. Blood and fecal samples were collected. Cats were then euthanatized, and postmortem examinations were performed. Tissues were examined grossly and histologically for signs of mycobacteriosis. Pooled tissue samples and fecal samples were submitted for mycobacterial culture. Blood samples were examined for evidence of tuberculosis by use of a comparative ELISA. Results-4 cats had positive responses for the ELISA, and 2 cats had suspicious responses. All tuberculin skin tests yielded negative results. No gross or histologic lesions of tuberculosis were detected in any tissues, and mycobacteria were not isolated from tissues or feces obtained from the 20 cats. Conclusions and Clinical Relevance-All cats that had positive or suspicious responses for the ELISA were offspring of the cat with tuberculosis. Evidence of tuberculosis was not seen in other cats at the residence, the owner, or the attending veterinarian. The most likely source of tuberculosis for the infected cat was through the consumption of M bovis-infected wildlife carcasses or offal. Because M bovis is endemic in wildlife in northeastern Michigan, there is a risk of exposure to tuberculosis in companion animals, their owners, and attending veterinarians.

Objective-To investigate the effects of preexisting FeLV infection or FeLV and feline immunodeficiency (FIV) coinfection on the pathogenicity of the small variant of Haemobartonella felis (Hfsm, California variant) in cats. Animals-20 FeLV infected, 5 FeLV-FIV coinfected, and 19 retrovirus-free cats. Procedure-A client-owned cat, coinfected with FeLV and Hfsm, was the source for Hfsm. Inoculum 1 (FeLV free) was obtained by passage of source Hfsm through 4 FeLV-resistant cats. Inoculum 2 was obtained by further passage of Hfsm (inoculum 1) through 2 specific pathogenfree cats. Results-A mild-to-moderate anemia started 21 days after inoculation, with its nadir occurring at 35 to 42 days after inoculation. Infection with Hfsm induced greater decrease in hemoglobin concentration in FeLV infected cats, compared with retrovirus free cats. Reticulocytosis, macrocytosis, and polychromasia of erythrocytes developed in anemic cats regardless of retrovirus infection status. Mean neutrophil counts decreased during the hemolytic episode. For most cats, the anemia was transient. Four FeLV infected cats, 1 of which was also FIV infected, developed fatal FeLV-associated myeloproliferative diseases. Of the surviving cats, 8 died over the next 24 months from other FeLV-related diseases. Hemolysis did not recur after the initial episode. Inoculum 1 induced more severe anemia than inoculum 2. Conclusions and Clinical Relevance-Our results support the clinical observation that cats coinfected with FeLV and H felis develop more severe anemia than cats infected with H felis alone. Infection with Hfsm may induce myeloproliferative disease in FeLV infected cats. The small variant of H felis may lose pathogenicity by passage through FeLV-free cats.

Objective-To determine whether intrathecal (IT) or IV administration of oxytocin will diminish amplitude of the reflex-evoked muscle action potential (REMP) in the digastricus muscle during electrical stimulation of the tooth pulp in anesthetized dogs, thus suggesting an analgesic effect for oxytocin. Animals-6 male Beagles that were 2 to 6 years old. Procedure-Dogs were used in a crossover design with at least a 5-day washout period between treatments. Each dog received morphine, saline (0.9% NaCl) solution, and oxytocin by both the IT and IV routes of administration. Noninvasive dental dolorimetry was used to assess changes in pain threshold following administration of treatments. Effectiveness of analgesia was determined on the basis of change in REMP amplitude in the digastricus muscle. Results-Morphine administered IV significantly inhibited REMP amplitude, compared with IV administration of saline solution or oxytocin. There was not a significant change in REMP amplitude between saline solution and oxytocin administered IV. Intrathecal administration of morphine significantly inhibited REMP amplitude, compared with IT administration of saline solution or oxytocin. Intrathecal administration of oxytocin significantly increased REMP amplitude, compared with IT administration of saline solution or morphine. Conclusions and Clinical Relevance-Although IV administration of oxytocin did not have an effect on REMP amplitude, compared with IV administration of saline solution, IT administration of oxytocin had the opposite effect of morphine and increased REMP amplitude of the digastricus muscle. These data do not support the use of oxytocin as an analgesic agent in dogs.

Objective-To compare experimentally induced concurrent infection with bovine viral diarrhea virus (BVDV) and bovine rotavirus (BRV) with infection of either virus alone in calves. Animals-Seventeen 1-day-old gnotobiotic calves. Procedure-Calves were allotted to 8 treatments as follows: group 1, mock-infected control calves (n = 2); group 2, inoculated with BVDV on day 1 (2); groups 3, 5, and 7, inoculated with BRV on days 1 (2), 4 (1), or 7 (2), respectively; and groups 4, 6, and 8, inoculated with BVDV on day 1 and with BRV on days 1 (2), 4 (2), or 7 (4), respectively. Concentrations of BVDV in serum and ileal tissues were measured, and BRV shedding in feces was determined. Histologic examination and immunohistochemical analysis were conducted to detect lesions and viral antigens. Results-Neonatal calves inoculated with BVDV alone or with BVDV on day 1 and BRV on day 7 developed villus atrophy and submucosal inflammation of the intestines. Concurrent BVDV and BRV infections acted synergistically in the intestinal tract, causing more severe enteric disease than infection with either virus alone. Severe lymphoid depletion was associated with BVDV infection in calves regardlesss of concurrent BRV infection. Conclusions and Clinical Relevance-Infection with BVDV played direct and indirect roles in enteritis in neonatal calves, causing villus atrophy in the duodenum and submucosal inflammation of the intestines. Also, BVDV potentiated effects of BRV. Concurrent infection with BVDV and BRV resulted in more severe enteric disease in neonatal calves than infection with BRV or BVDV alone.

Objective-To determine the effects of recombinant equine interleukin -1beta (reIL-1beta) and 4 anti-inflammatory compounds on the expression and activity of cyclooxygenase (COX)-2 in cultured equine chondrocytes. Sample Population-Articular cartilage from 9 young adult horses. Procedure-Reverse transcriptase-polymerase chain reaction methods were used to amplify a portion of equine COX-2 to prepare a cDNA probe. Northern blot analysis was used to quantify the expression of COX-2 in first-passage cultures of equine articular chondrocytes propagated in media containing dexamethasone (DEX), phenylbutazone (PBZ), polysulfated glycosaminoglycan, and hyaluronan, each at concentrations of 10 and 100 micrograms/ml and each with or without reIL-1beta. A commercial immunoassay was used to determine prostaglandin E2 (PGE2) concentrations in conditioned medium of similarly treated cells to quantify COX-2 activity. Results-Addition of reIL-1beta increased the expression of COX-2 in a dose-dependent manner, which was paralleled by an increased concentration of PGE2 in culture medium. Concentration of PGE2 in spent medium from reIL-1beta-treated chondrocytes was significantly reduced by DEX and PBZ; however, only DEX significantly reduced gene expression of COX-2. Conclusions and Clinical Relevance-Prostaglandin E2 is considered to be an important mediator in the pathophysiologic processes of arthritis, and cultured chondrocytes respond to interleukin-1 with enhanced expression and activity of COX-2. Palliative relief in affected horses is probably attributable, in part, to inhibition of PGE2 synthesis; however, analysis of these data suggests that of the 4 compounds tested, only DEX affects pretranslational regulation of the COX-2 gene in cultured equine chondrocytes.

Objective-To evaluate the effect of prolonged water exposure on tissue mass and solutes of outer and inner layers of the stratum medium, sole, frog, and the stratum medium (SMZA) zona alba layer of horses' hooves. Specimen Population-10 hooves from 10 horses without foot abnormalities. Procedure-Hoof wall tissue specimens were obtained and immersed for 10 days in distilled deionized water. Serial changes in mass were recorded during the immersion period. Subsequently, osmolarity and Na+, K+, Cl-, and protein concentrations of the immersion solution were quantified. Results-Fully cornified outer hoof wall, sole, and frog epidermal structures increased in mass, whereas the SMZA lost mass when immersed in water. All hoof structures had a variable loss of crystalloids during immersion, but none of the specimens lost proteins. The frog epidermis was distinct in that total solute lost during immersion could not be ascribed to Na+, K+, and Cl-. Conclusions and Clinical Relevance-Data support a 2-compartment model for the fully cornified outer stratum medium, frog, and sole that permits the exchange of crystalloids, but not proteins, across the cell membrane and infers that topical agents containing proteins cannot benefit the hoof. The unique osmotic behavior of the SMZA relative to other hoof structures suggests the hypothesis that it is composed of transitional epithelial cells. The solutes lost from frog epithelium are interpreted to reflect its unique lipid composition.

Objective-To develop polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis for molecular typing of strains of Streptococcus zooepidemicus and to use the new typing method to analyze a collection of isolates from the respiratory tract of Thoroughbreds. Sample Population-10 strains of S zooepidemicus, 65 isolates from the respiratory tract of 9 yearlings following long distance transportation, and 89 isolates from tracheal aspirates of 20 foals with pneumonia. Procedure-Phenotypic variations in the SzP protein were detected by western immunoblot analysis. Using PCR-RFLP analysis, genotypes were obtained with primer sets from the SzP gene, followed by restriction endonuclease digestion of the amplicons. Results-Unique genotypic patterns were obtained with a primer set designed from both ends of the structural gene and the restriction endonuclease Dde I. Forty-five isolates from the lymphoid tissue within the pharyngeal recess (ie, pharyngeal tonsil) of yearlings included 10 SzP genotypes and SzP phenotypes. Isolates from the trachea of each yearling were of a single genotype that was also present among isolates from the pharyngeal tonsil of the same horses. Isolates from tracheal aspirates of foals belonged to 14 genotypes. Conclusion and Clinical Relevance-Analysis of the SzP gene by use of PCR-RFLP was effective for molecular typing of strains of S zooepidemicus in the study of respiratory tract disease in horses. Results of PCR-RFLP analysis indicate that a single strain of S zooepidemicus can migrate from the pharyngeal tonsil to the trachea at a high rate in horses undergoing long distance transportation.

Objective-To determine plasma concentrations of adrenocorticotrophic hormone (ACTH) and alpha-melanocyte stimulating-hormone (α-MSH) in healthyferrets and ferrets with hyperadrenocorticism. Animals-16 healthy, neutered, privately owned ferrets, 28 healthy laboratory ferrets (21 sexually intact and 7 neutered), and 28 ferrets with hyperadrenocorticism. Procedures-Healthy ferrets were used for determination of reference plasma concentrations of ACTH and alpha-MSH. Diagnosis of hyperadrenocorticism was made on the basis of history, clinical signs, urinary corticoid-to-creatinine ratios, ultrasonography of the adrenal glands, and macroscopic or microscopic evaluation of the adrenal glands. Blood samples were collected during isoflurane anesthesia. Plasma concentrations of ACTH and α-MSH were measured by radioimmunoassay. Results-Plasma concentrations of ACTH in 23 healthy neutered ferrets during the breeding season ranged from 4 to 145 ng/L (median, 50 ng/L). Plasma concentrations of α-MSH in 44 healthy neutered or sexually intact ferrets during the breeding season ranged from < 5 to 617 ng/L (median, 37 ng/L). Reference values (the central 95% of the values) for ACTH and α-MSH were 13 to 100 ng/L and 8 to 180 ng/L, respectively. Plasma concentrations of ACTH and α-MSH in ferrets with hyperadrenocorticism ranged from 1 to 265 ng/L (median, 45 ng/L) and 10 to 148 ng/L (median, 46 ng/L), respectively. These values were not significantly different from those of healthy ferrets. Plasma ACTH concentrations of sexually intact female ferrets in estrus were significantly higher than those of neutered females. Conclusions and Clinical Relevance-Ferrets with hyperadrenocorticism did not have detectable abnormalities in plasma concentrations of ACTH or α-MSH. The findings suggest that hyperadrenocorticism in ferrets is an ACTH and α-MSH-independent condition.

Objective-To evaluate a model for atopic dermatitis (AD) and to measure the effect of sensitization in Beagles genetically predisposed to produce high serum concentrations of allergen specific IgE. Animals-22 laboratory Beagles. Procedure-Seventeen dogs were sensitized from birth to 3 allergens (recombinant birch pollen, Dermatophagoides pteronyssinus, and D farinae). Five nonsensitized dogs from the same litters served as controls. Clinical scoring, regular intradermal testing, measurement of serum concentrations of allergen-specific IgE, and collection of biopsy specimens of skin at 23, 32, and 43 weeks of age were performed. Serial tissue sections were stained for identification of IgE+ cells, mast cells and their subtypes, T-cells, Langerhans cells, and major histocompatibility complex class-II+ cells. At the age of 15 months, dogs were continuously exposed to 2 µg of mite allergen/ g of dust. Results-Sensitized dogs had positive intradermal test reactions and significantly higher serum concentrations of allergen specific IgE, compared with nonsensitized dogs. In sensitized and nonsensitized dogs, a significantly higher number of mast cells was found at predilection sites, compared with the control biopsy site. The number of mast cells at predilection sites increased with age. Sensitization significantly increased the number of epidermal Langerhans cells by 23 weeks of age. The number of epidermal Langerhans cells significantly increased in nonsensitized dogs by 32 weeks of age. Clinical scoring only revealed mild transient erythema in some dogs. Conclusion and Clinical Relevance-Increases in concentrations of serum allergen-specific IgE and exposure to allergens is not sufficient to induce clinical signs of AD in genetically predisposed dogs.

Objective-To determine whether changes in amplitude of the reflex-evoked muscle action potential (REMP) elicited by noninvasive dental dolorimetry (electrical stimulation of the tooth pulp) in anesthetized dogs may be used to objectively evaluate the effectiveness of IV and intrathecal (IT) administration of morphine. Animals-6 male Beagles that were 2 to 6 years old. Procedure-Dogs were used in a crossover design with at least a 5-day washout period between treatments. Each dog received morphine, saline (0.9% NaCl) solution, and oxytocin via the IV and IT routes of administration; however, only results for morphine and saline treatments were reported here. Dogs were anesthetized and prepared for noninvasive dental dolorimetry. After IV or IT administration, electrical stimulation was applied to a tooth, and REMPs of the digastricus muscle were recorded at 5-minute intervals for 60 minutes. To determine differences in REMP amplitude between treatments, a linear regression line was fitted for each dog-treatment combination. Results-The IV administration of morphine significantly inhibited REMP amplitude, compared with IV administration of saline solution. Intrathecal administration of morphine significantly inhibited REMP amplitude, compared with IT administration of saline solution. Conclusions and Clinical Relevance-Noninvasive dental dolorimetry in anesthetized dogs has promise as a technique for use in evaluating the analgesic potential of drugs administered IV and IT through evaluation of their effect on REMP amplitude recorded for the digastricus muscle.