Objective-To examine the role of bovine viral diarrhea virus (BVDV) biotype on the establishment of fetal infection in cattle. Animals-30 mixed-breed pregnant cows. Procedure-Pregnant cows were inoculated oronasally with either i-VVNADL, originating from an infectious BVDV cDNA clone of the National Animal Disease Laboratory (NADL) isolate, or the parental virus stock, termed NADL-A. Results-All cows developed neutralizing antibodies to BVDV, and virus was commonly isolated from peripheral blood mononuclear cells or nasal swab specimens of NADL-A inoculated cows; however, virus was rarely isolated from specimens of i-VVNADL inoculated cows. i-VVNADL did not cause fetal infection, whereas all fetuses harvested from NADL-A inoculated cows at 6 weeks after inoculation had evidence of infection. Immunoblot analysis of fetal virus isolates revealed the absence of NS3, confirming a noncytopathic (NCP) biotype BVDV in the NADL-A stock. The sequence of the NCP contaminant (termed NADL-1102) and the i-VVNADL genome were virtually identical, with the exception of a 270 nucleotide-long insert in the i-VVNADL genome. Phylogenetic analyses revealed that NADL-1102 forms a monophyletic group with 6 other NADL genomes. Conclusions and Clinical Relevance-These data suggest that the contaminating NCP virus in the NADL-A stock was the ancestral NADL virus, which originally infected a bovine fetus and recombined to produce a cytopathic (CP) variant. Following oronasal infection of pregnant cows, viremia and transplacental transmission of CP BVDV to the fetus is rare, compared with the high occurrence of maternal viremia and fetal infection observed with NCP BVDV.

Objective-To determine whether Haemobartonella canis and Mycoplasma haemofelis (formerly known as H felis [large form]) can be differentiated by use of comparative analysis of gene sequences. Sample Population-Blood samples obtained from 3 dogs infected with H canis and 2 cats infected with M haemofelis. Procedure-The partial 16S rDNA and ribonuclease P RNA (RNase P) genes were amplified, cloned, and sequenced in blood samples obtained from H canis-infected dogs and M haemofelis-infected cats. The DNA sequences were subjected to comparative analysis. Results-The 16S rDNA sequences of H canis and M haemofelis were nearly identical (homology of 99.3 to 99.7%). In contrast, RNase P gene sequences had a lower degree of sequence homology between the 2 organisms (94.3 to 95.5%). Conclusions and Clinical Relevance-Haemobartonella canis and M haemofelis are not identical organisms. Molecular differentiation of H canis and M haemofelis is more clearly evident by use of comparative analysis of RNase P gene sequences than by comparative analysis of 16S rDNA gene sequences.

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 compare plasma and synovial fluid endothelin-1 (ET-1) and nitric oxide (NO) concentrations in clinically normal horses and horses with joint disease. Animals-36 horses with joint disease, and 15 horses without joint disease. Procedure-Horses with joint disease were assigned to 1 of the 3 groups (ie, synovitis, degenerative joint disease [DJD], or joint sepsis groups) on the basis of findings on clinical and radiographic examination and synovial fluid analysis. Endothelin-1 and NO concentrations were measured in plasma from blood samples, collected from the jugular vein and ipsilateral cephalic or saphenous vein of the limb with an affected or unaffected joint, as well as in synovial fluid samples obtained via arthrocentesis from the involved joint. Results-Plasma ET-1 concentrations between affected and unaffected groups were not significantly different. Median concentration and concentration range of ET-1 in synovial fluid obtained from the joint sepsis group (35.830 pg/mL, 7.926 to 86.614 pg/mL; n = 7) were significantly greater than values from the synovitis (17.531 pg/mL, 0.01 to 46.908 pg/mL; 18), DJD (22.858 pg/mL, 0.01 to 49.990 pg/mL; 10), and unaffected (10.547 pg/mL, 0.01 to 35.927 pg/mL; 10) groups. Plasma and synovial fluid NO concentrations between affected and unaffected groups were not significantly different. Conclusions and Clinical Relevance-Endothelin-1 is locally synthesized in the joints of horses with various types of joint disease. Synovial fluid concentrations of ET-1 varied among horses with joint disease, with concentrations significantly higher in the synovial fluid of horses with joint sepsis. These results indicate that ET-1 may play a role in the pathophysiologic mechanism of joint disease in horses.

Objective-To characterize and compare in vitro contractility patterns of sections of abomasal wall harvested from cattle of 3 dairy breeds. Sample Population-Longitudinal and circular smooth muscle preparations harvested from the antrum and body of the abomasum of 30 recently slaughtered Holstein-Friesian, Brown Swiss, and Simmental X Red Holstein cows. Procedure-Spontaneous isometric contractions of specimens in tissue baths of modified Krebs solution were recorded during a 4-hour period. Maximal amplitude, frequency of contractions, and change of basal tension were used to characterize contractility. Statistical analyses were used to test for differences among time periods, among breeds, between specimen locations, and between fiber orientations. Results-Myoactivity patterns of abomasal smooth muscle preparations are highly variable and differ on the basis of location and fiber orientation. Frequency of contractions differed significantly among time periods for longitudinally oriented specimens with decreasing frequencies of contractions over time. Maximal amplitude of the longitudinally oriented specimens from the antrum increased significantly, whereas maximal amplitude of the circularly oriented specimens from the antrum decreased significantly. Values did not differ significantly among breeds. Conclusions and Clinical Relevance-Patterns of spontaneous contractility of abomasal wall specimens are not homogeneous. During a 4-hour recording period, maximal amplitude and frequency of contractions of specimens varied significantly with respect to orientation and location; however, spontaneous contractile myoactivity did not differ significantly among breeds. Therefore, breed predisposition for displaced abomasum is not correlated with spontaneous activity of smooth muscle specimens.

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 compare sensitivity of several methods of bacteriologic culture of pooled bovine fecal samples for detection of Mycobacterium paratuberculosis and evaluate homogeneity in number of M paratuberculosisin pooled fecal samples. Sample Population-Feces from 10 dairy cows that shed M paratuberculosis at various concentrations and 1 dairy cow known to be free of infection with M paratuberculosis. Procedure-5 fecal pooling methods, 2 culture methods, and 2 pool sizes were evaluated. Each pooled sample contained 1 infected sample and 4 or 9 uninfected samples. Results-Sensitivity of detection of M paratuberculosis was greater with smaller pool size (5 vs 10 samples/ pool). Detection sensitivity was also associated with concentration of bacteria in the infected sample. Results indicated that, compared with concurrent bacterial culture of individual infected samples, 37 to 44% of pooled samples with low bacterial concentrations yielded positive culture results and 94% of pooled samples with high bacterial concentrations yielded positive results. Conclusions and Clinical Relevance-Bacteriologic culture of pooled fecal samples may provide a valid and cost-effective method of detecting M paratuberculosis infection in cattle herds.

Objective-To assess the heritability of pancreatic acinar atrophy (PAA) in German Shepherd Dogs (GSDs) in the United States. Animals-135 GSDs belonging to 2 multigenerational pedigrees. Procedure-Two multigenerational pedigrees of GSDs with family members with PAA were identified. The clinical history of each GSD enrolled in the study was recorded, and serum samples for canine trypsinlike immunoreactivity (cTLI) analysis were collected from 102 dogs. Dogs with a serum cTLI concentration ≤ 2.0 µg/L were considered to have exocrine pancreatic insufficiency (EPI) and were assumed to have PAA. Results-Pedigree I consisted of 59 dogs and pedigree II of 76 dogs. Serum cTLI concentrations were measured in 48 dogs from pedigree I and 54 dogs from pedigree II. A total of 19 dogs (14.1%) were determined to have EPI, 9 in pedigree I (15.3%) and 10 in pedigree II (13.6%). Of the 19 dogs with EPI, 8 were male and 11 were female. Conclusion and Clinical Relevance-Evaluation of data by complex segregation analysis is strongly suggestive of an autosomal recessive mode of inheritance for EPI in GSDs in the United States.

Objective-To investigate whether upper airway sounds of horses exercising with laryngeal hemiplegia and alar fold paralysis have distinct sound characteristics, compared with unaffected horses. Animals-6 mature horses. Procedure-Upper airway sounds were recorded in horses exercising on a high-speed treadmill at maximum heart rate (HRMAX) under 3 treatment conditions (ie, normal upper airway function [control condition], and after induction of left laryngeal hemiplegia or bilateral alar fold paralysis) in a randomized crossover design. Fundamental frequency, spectrograms using Gabor transform, and intensity characteristics of acquired sounds (peak sound level [soundpeak] and highest frequency of at least –25 dB sound intensity [F25max]) were evaluated. Results-Evaluation of the fundamental frequency of the time domain signal was not useful. Sensitivity and specificity (83 and 75%, respectively) of spectrograms were greatest at maximal exercise, but the exact abnormal condition was identified in evaluation of only 12 of 18 spectrograms. Increased accuracy was obtained using soundpeak and F25max as discriminating variables. The use of soundpeak discriminated between control and laryngeal hemiplegia conditions and F25max between laryngeal hemiplegia and alar fold paralysis conditions. This increased the specificity of sound analysis to 92% (sensitivity 83%) and accurately classified the abnormal state in 92% of affected horses. Conclusions and Clinical Relevance-Sound analysis might be a useful adjunct to the diagnosis and evaluation of treatment of horses with upper airway obstruction, but would appear to require close attention to exercise intensity. Multiple measurements of recorded sounds might be needed to obtain sufficient accuracy for clinical use.

Objective-To evaluate in vivo activityin dogs of meloxicam or aspirin, previously shown in vitro to be a selective cyclooxygenase-2 (COX-2) inhibitor (COX-1 sparing drug), or a nonselective COX inhibitor, respectively. Animals-12 male dogs with unilateral osteoarthritis of the stifle joint. Procedure-Each dog was treated in a crossover design with aspirin or meloxicam for 21 days. Prostaglandin E2 (PGE2) concentrations were measured at days 0 (baseline), 7, and 21 of each treatment period in lipopolysaccharide (LPS)-stimulated blood, synovial fluid collected by arthrocentesis, and endoscopic gastric mucosal biopsy specimens. Thromboxane B2 (TXB2) was evaluated in blood on days 0, 7, and 21 of each treatment period. Results-Aspirin administration significantly suppressed PGE2 concentrations in blood, gastric mucosa, synovial fluid, and suppressed TXB2 concentration in blood at days 7 and 21. Meloxicam administration significantly suppressed PGE2 concentrations in blood and synovial fluid at days 7 and 21, but had no effect on concentrations of TXB2 in blood or PGE2 in gastric mucosa. Suppression of LPS-stimulated PGE2 concentrations in blood and synovial fluid by aspirin and meloxicam administration is consistent with activity against the COX-2 isoenzyme. Suppression of concentrations of PGE2 in the gastric mucosa and TXB2 in blood by aspirin administration is consistent with activity against COX-1. Meloxicam, in contrast, had a minimal effect on functions mediated by COX-1. Conclusions and Clinical Relevance-Meloxicam acts in vivo in dogs as a COX-1 sparing drug on target tissues by sparing gastric PGE2 synthesis while retaining antiprostaglandin effects within inflamed joints.