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Abstract

Objective—To determine whether commercial Mycoplasma hyopneumoniae bacterins sold for use in swine contain porcine torque teno virus (TTV).

Sample Population—22 commercially available M hyopneumoniae bacterins.

Procedures—Direct and nested PCR assays for genogroup-specific TTV DNAs were performed on serials of M hyopneumoniae bacterins by use of published and custom-designed primer pairs at 3 laboratories in North America and Europe.

Results—Of the 22 bacterins tested by use of direct and nested PCR assays, 7 of 9 from the United States, 2 of 5 from Canada, and 4 of 8 from Europe contained genogroup 1– and genogroup 2–TTV DNAs. In some bacterins, the TTV DNAs were readily detected by use of direct PCR assays.

Conclusions and Clinical Relevance—Analysis of these data indicated that many of the commercially available M hyopneumoniae bacterins were contaminated with TTV DNA. It is possible that some of these bacterins could inadvertently transmit porcine TTV infection to TTV-naïve swine.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether vaccine site-associated sarcomas (VSS) from cats contain papillomavirus antigen or DNA.

Sample Population—50 formalin-fixed paraffinembedded tissue blocks of VSS from cats.

Procedure—Sections from each tissue block were evaluated for papillomavirus antigen by use of an avidin-biotin-complex immunohistochemical staining method, using rabbit anti-bovine papillomavirus type-1 antibody. The DNA was extracted from sections of each tissue block, and polymerase chain reaction assays were performed, using primers designed to amplify regions of the E5 gene of bovine papillomavirus and consensus primers designed to amplify a region of the L1 gene of animal papillomaviruses. Sections from 20 of the tissue blocks were evaluated by use of nonradioactive in situ hybridization for bovine papillomavirus DNA.

Results—Papillomavirus antigen and DNA were not detected in any of the VSS.

Conclusions and Clinical Relevance—Results suggest that papillomaviruses likely do not have any direct involvement in the pathogenesis of VSS in cats. (Am J Vet Res 2001;62:833–839)

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To quantify acute immunologic and metabolic responses of beef heifers following topical administration of transdermal flunixin meglumine (TDFM) at various times relative to bovine herpesvirus 1 (BHV1) and Mannheimia haemolytica challenges.

ANIMALS

32 beef heifers (mean body weight, 170 kg).

PROCEDURES

Heifers were assigned to 1 of 4 groups. Heifers in the control group did not receive TDFM, whereas 1 dose of TDFM (3.3 mg/kg) was topically applied to heifers of groups A, V, and B at −144, −72, and 0 hours. All heifers were inoculated with 1 × 108 plaque-forming units of BHV1 in each nostril at −72 hours and with 1.18 × 106 CFUs of M haemolytica intratracheally at 0 hours. Vaginal temperature was recorded and blood samples were collected for quantification of select immunologic and metabolic biomarkers at predetermined times from −144 to 360 hours.

RESULTS

Mean vaginal temperature was similar between group A and the control group. Mean vaginal temperatures for groups V and B were generally lower than that for the control group following BHV1 and M haemolytica challenges, respectively. Mean neutrophil oxidative burst capacity and L-selectin expression at 0 hours were significantly decreased for group V relative to the other groups. Other biomarkers did not differ among the groups at any time.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that topical administration of TDFM to beef cattle effectively alleviated pyrexia without adverse effects on acute immunologic or metabolic responses when TDFM was administered at the same time as, but not before, respiratory pathogen challenge.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether porcine dermatitis and nephropathy syndrome (PDNS) could be experimentally induced in gnotobiotic swine.

Sample Population—Plasma samples from 27 sows and 20 conventional weaned piglets were obtained, and 30 gnotobiotic pigs were used in experiments.

Procedures—3 experiments were conducted. Groups of 3-day-old gnotobiotic pigs were inoculated with pooled plasma samples obtained from healthy feeder pigs in a herd that was in the initial phases of an outbreak of respiratory disease; gross and histologic lesions of PDNS were detected in the inoculated pigs. In a second experiment, 2- and 3-day-old gnotobiotic pigs were inoculated with porcine reproductive respiratory syndrome virus (PRRSV) and with PRRSV-negative tissue homogenate containing genogroup 1 torque teno virus (g1-TTV). Lesions of PDNS were detected.

Results—Pigs inoculated with pooled plasma or the combination of tissue-culture–origin PRRSV and g1-TTV tissue homogenate developed systemic hemostatic defects, bilaterally symmetric cutaneous hemorrhages, generalized edema, icterus, bilaterally symmetric renal cortical hemorrhage, dermal vasculitis with hemorrhage, and interstitial pneumonia consistent with a clinical and pathologic diagnosis of PDNS. The PRRSV RNAs and g1-TTV DNAs were detected in plasma; all pigs seroconverted to PRRSV, and all had negative results for porcine circovirus type 2 when tested by use of PCR assays.

Conclusions and Clinical Relevance—These data suggested that PDNS is a manifestation of disseminated intravascular coagulation in swine. For the experimental conditions reported here, combined infection with g1-TTV and PRRSV was implicated in the genesis of these lesions.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine whether immunity against bovine respiratory syncytial virus (BRSV) mitigates the effects of 3-methylindole (3MI) on occurrence of bovine respiratory tract disease (BRD) and rate of gain in feedlot cattle.

Animals—254 mixed-breed beef cattle.

Procedure—Cattle were randomly assigned to 1 of 3 groups at the time of arrival at the feedlot. One group was vaccinated with an inactivated BRSV vaccine, another was vaccinated with a modified-live BRSV vaccine, and the third was maintained as unvaccinated control cattle. On days 0 and 28, serum BRSV antibody concentrations were measured, using serum neutralizing and ELISA techniques. Serum 3MI concentrations were measured at feedlot arrival and 3 days later. Cattle were monitored for development of BRD. At slaughter, lungs were evaluated grossly for chronic lesions.

Results—Higher serum 3MI concentrations early in the feeding period were associated with lower mean daily gain. Control cattle were more likely to be treated for BRD after day 3, compared with cattle vaccinated with the modified-live BRSV vaccine. Humoral immunity against BRSV did not appear to modify the effect of 3MI on development of BRD or mean daily gain.

Conclusions and Clinical Relevance—Results suggest that abrogating the effects of 3MI and BRSV infection may improve the health and growth performance of feedlot cattle. However, in this study, immunity against BRSV did not appear to protect against the potential synergism between 3MI and BRSV infection, possibly because of the slow rates of gain of cattle included in the study or timing of sample collection. (Am J Vet Res 2000;61:1309–1314)

Full access
in American Journal of Veterinary Research