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  • Author or Editor: Edward J. Dubovi x
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Abstract

Objective—To compare 2 assays for use in the identification of dogs with a protective antibody titer (PAT) against canine parvovirus (CPV) and canine distemper virus (CDV).

Design—Prospective cross-sectional study.

Animals—431 dogs admitted to a municipal animal shelter in north central Florida.

Procedures—Blood samples were collected from dogs on the day of admission to the shelter. Serum was obtained, criterion-referenced assays were used to identify dogs that had PATs against CPV (titers ≥ 80; hemagglutination inhibition assay) and CDV (titers ≥ 32; virus neutralization assay), and results were compared with results of a semiquantitative ELISA and an immunofluorescence assay (IFA).

Results—For correct identification of dogs that had PATs against viruses, the ELISA had significantly higher specificity for CPV (98%) and CDV (95%) than did the IFA (82% and 70%, respectively) and had significantly lower sensitivity for CDV (88%) than did the IFA (97%); the sensitivity for CPV was similar (ELISA, 98%; IFA, 97%). Overall diagnostic accuracy was significantly greater with the ELISA than with the IFA. Predictive value of a positive result for PATs was significantly higher with the ELISA for CPV (99%) and CDV (93%) than with the IFA (92% and 71 %, respectively).

Conclusions and Clinical Relevance—The ELISA had fewer false-positive results than did the IFA and could be performed on-site in shelters in < 1 hour. Accuracy and practicality of the ELISA may be useful for identifying the infection risk of dogs exposed during outbreaks attributable to CPV and CDV infections in shelters.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the frequency of viral detection in conjunctival samples from client-owned domestic dogs with naturally acquired idiopathic conjunctivitis and to identify signalment, historical, and clinical findings positively associated with viral detection.

Design—Case-control study

Animals—30 dogs with naturally acquired idiopathic conjunctivitis and a control population of 30 dogs without ocular disease.

Procedures—Complete physical and ophthalmic examinations were performed for each dog. Conjunctival swab specimens were analyzed by use of virus isolation and PCR assays for the following viruses: canine adenovirus-2 (CAV-2), canine distemper virus, canine herpesvirus-1 (CHV-1), canine parainfuenza virus, canine respiratory coronavirus, infuenza A virus, and West Nile virus. Signalment, clinical, and historical information was recorded and compared between study groups.

Results—Viruses were detected by either virus isolation or PCR methods significantly more frequently in conjunctival samples from dogs with conjunctivitis (7/30 [23.3%]) than dogs without conjunctivitis (0/30 [0%]). Canine herpesvirus-1 was isolated from 2 conjunctival samples and detected by use of PCR assay in 5 conjunctival samples. Canine adenovirus-2 was isolated from 1 conjunctival sample and detected by use of PCR assay in 2 conjunctiva samples. Sexually intact dogs and frequent exposure to dogs outside the household were positively associated with viral detection in the conjunctivitis group

Conclusions and Clinical Relevance—Results suggested that CHV-1 and CAV-2 are common etiologic agents of conjunctivitis in domestic dogs. Risk factors for viral conjunctivitis in dogs reflected increased exposure to other dogs and opportunities for contact with infectious secretions.

Full access
in Journal of the American Veterinary Medical Association

Summary

A total of 21 calves were inoculated IV with 1 of the following isolates of bovine viral diarrhea virus (BVDV); CD87 (n = 10), NY-1 (n = 3), NADL (n = 5), or were sham-inoculated with virus-free medium (n = 3). Subsequent to inoculation, platelet counts were monitored to detect differences between noncytopathic (CD87, NY-1) and cytopathic (NADL) isolates in their ability to induce thrombocytopenia. Platelet count decrease throughout infection was statistically analyzed by comparing the slope of the line drawn from the count on the day of infection to the lowest count achieved by that calf. Significant difference was observed in the CD87-inoculated calves and in the NY-1-inoculated calves, compared with those of the same control group. Significant difference was not observed in the slope of platelet count decrease between the cytopathic NADL-infected calves and control-group calves. The data indicate that noncytopathic BVDV isolates may more easily induce thrombocytopenia than do cytopathic isolates in immune-naive, immunocompetent calves; acute infection with 1 cytopathic BVDV isolate (NADL) did not induce thrombocytopenia. In addition, although each calf seroconverted, virus was rarely isolated from mononuclear cells obtained from calves with cytopathic infections. At some point after infection, virus was always isolated from each of the calves undergoing noncytopathic infections, and occasionally, transient association of noncytopathic BVDV antigen with platelets was observed during these infections.

Free access
in American Journal of Veterinary Research

SUMMARY

A retrospective study was designed to determine the distribution of equine monocytic ehrlichiosis among the equine population in New York state, and to identify factors associated with risk of disease. Serum samples submitted to the diagnostic laboratory of the university during the period from January 1985 through December 1986 were examined for antibodies to Ehrlichia risticii, using the indirect fluorescent antibody technique. Factors evaluated included geographic origin and date of submission of the sample, and age, breed, and sex of the horse. Logistic regression analysis was used to identify which factors were significantly associated with the risk of seropositivity to E risticii, while simultaneously controlling for other factors.

Of the 2,579 tested samples, 1,950 (76%) had positive results. Factors significantly associated with risk of seropositivity to E risticii were: breed of the horse (Thoroughbreds were 3 times more likely to have been exposed to E risticii, compared with non-Standardbred, non-Thoroughbred breeds); sex (female horses were 2.7 times more likely to have been exposed, compared with male horses); age of the horse (the risk of being exposed to E risticii increased with age, peaked at around 12 years, and decreased thereafter); and month of submission (horses tested during November and December had the highest odds of being seropositive [odds ratio = 2.1], and horses tested during March through April were least likely to be seropositive [odds ratio = 0.5], compared with horses tested during January and February).

Free access
in American Journal of Veterinary Research

SUMMARY

A panel of 40 monoclonal antibodies (MAb) specific for bovine viral diarrhea virus (bvdv) was produced, and each MAb was characterized and grouped according to its viral protein specificity, immunoglobulin subclass, virus-neutralizing activity, and immunoreactivity with a large collection of bvdv isolates. The MAb were found to be specific for 1 of 3 sets of related viral-induced proteins found in cells infected with the Singer strain of bvdv. Group-1 MAb were specific for the 80- and 118-kilodalton (kD) proteins of bvdv. Group-2 MAb recognized 3 proteins with molecular sizes of 54, 56, and 58 kD. Group-3 MAb recognized a 43- and a 65-kD protein. The MAb belonged to either the IgGl, IgG2a, IgG2b, IgG3 subclasses or the IgE class of mouse immunoglobulin. All MAb in group 2 were able to neutralize bvdv and had neutralization titers that ranged from 24 to 1,600,000. The reactivity of the MAb with numerous field isolates of bvdv was highly variable. Both cytopathic and noncytopathic biotypes of bvdv were examined and had the same degree of antigenic variation. The greatest degree of variation was detected with group-2 MAb. The data demonstrate that bvdv isolates have a high degree of antigenic variation that is largely confined to the envelope glycoproteins associated with virus neutralization. The results also suggest that antigenic variability of this virus is important in the development and severity of the disease it causes.

Free access
in American Journal of Veterinary Research

Abstract

Objectives

To locate counties within New York state with a high seroprevalence among the equine population, to determine host, management, and environmental factors that were associated with seropositivity to Ehrlichia risticii, and to determine evidence for arthropod- or helminth-mediated transmission of E risticii to horses.

Design

Cross-sectional study.

Sample Population

A random sample of 3,000 of the 39,000 equine operations in New York state was selected, and 2,587 horses from 511 operations were tested.

Procedure

Blood samples were collected from horses and tested for seropositivity, using the indirect fluorescent antibody technique. Data on each horse and each farm's management were obtained by personal interview. The significance of each factor on the risk of seropositivity was evaluated, using mixed-effect logistic regression.

Results

The seroprevalence among E risticii-nonvaccinated horses was 7.3%. The county-specific seroprevalence ranged from 0 to 27%, with higher-risk counties located at low elevation. Farms at higher risk for having seropositive horses were located predominately at low elevation with no bodies of water nearby.

Risk of seropositivity was associated with time spent in a stall or run-in shed, with frequency of application of fly spray, and, depending on duration of residency at the farm, with frequency of deworming with benzimidazole and pyrantel. Standardbreds were 2 to 3 times more likely to have been exposed, compared with Thoroughbreds. Depending on duration of residency at the farm, male and middle-age horses were at higher risk.

Up to 32% of the variance for a horse to test seropositive for E risticii on the logit scale was attributable to farm-level random effects, but the nested social group random effect was not significant.

Conclusions

Arthropods and helminths may have a role in the transmission of this disease. Several management factors may directly or indirectly modify the risk of exposure to E risticii, allowing for the possibility of additional control measures besides traditional vaccination strategies.(Am J Vet Res 1996;57:278-285 )

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine the frequency and duration of feline panleukopenia virus (FPV) vaccine-induced interference with fecal parvovirus diagnostic testing in cats.

Design—Prospective controlled study.

Animals—Sixty-four 8- to 10-week-old specific-pathogen–free kittens.

Procedures—Kittens were inoculated once with 1 of 8 commercial multivalent vaccines containing modified-live virus (MLV) or inactivated FPV by the SC or intranasal routes. Feces were tested for parvovirus antigen immediately prior to vaccination, then daily for 14 days with 3 tests designed for detection of canine parvovirus. Serum anti-FPV antibody titers were determined by use of hemagglutination inhibition prior to vaccination and 14 days later.

Results—All fecal parvovirus test results were negative prior to vaccination. After vaccination, 1 kitten had positive test results with test 1, 4 kittens had positive results with test 2, and 13 kittens had positive results with test 3. Only 1 kitten had positive results with all 3 tests, and only 2 of those tests were subjectively considered to have strongly positive results. At 14 days after vaccination, 31% of kittens receiving inactivated vaccines had protective FPV titers, whereas 85% of kittens receiving MLV vaccines had protective titers.

Conclusions and Clinical Relevance—Animal shelter veterinarians should select fecal tests for parvovirus detection that have high sensitivity for FPV and low frequency of vaccine-related test interference. Positive parvovirus test results should be interpreted in light of clinical signs, vaccination history, and results of confirmatory testing. Despite the possibility of test interference, the benefit provided by universal MLV FPV vaccination of cats in high-risk environments such as shelters outweighs the impact on diagnostic test accuracy.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To characterize clinical ocular disease, viral shedding, and serologic response associated with primary canine herpesvirus-1 (CHV-1) ocular infection in naïve adult dogs.

Animals—12 specific pathogen-free adult Beagles.

Procedures—Dogs were topically inoculated in the right eye with CHV-1 (infection group; n = 8) or virus-free medium (control group; 4). Dogs were inoculated with or without corneal microtrephination and subconjunctivally administered corticosteroids. Conjunctiva, buffy coat, and serum samples for real-time PCR assay, virus isolation, and serum neutralization (SN) antibody titers were collected until postinfection day (PID) 224, and general physical and ophthalmologic examinations were performed.

Results—Dogs in the infection group developed bilateral, mild to moderate conjunctivitis that reached maximal intensity on PIDs 7 to 10. Ocular viral shedding was detected in all dogs in the infection group between PIDs 3 and 10. Infected dogs developed CHV-1 SN antibody titers, beginning at PID 7 and peaking on PID 21. All buffy coat PCR assay results were negative. Corneal microtrephination and subconjunctival corticosteroid administration did not significantly affect clinical disease or viral shedding. Following recovery from primary infection, dogs remained clinically normal, did not shed virus, and had slowly decreasing SN antibody titers. Dogs in the control group did not develop conjunctivitis, shed virus, or develop CHV-1 SN antibody titers.

Conclusions and Clinical Relevance—Primary ocular infection of adult dogs with CHV-1 was associated with self-limiting conjunctivitis and ocular viral shedding, which was evident in the absence of clinically detectable keratitis or systemic disease. Features of this infection resembled herpes simplex virus primary ocular infection in humans.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To estimate the seroprevalence of antibodies against H3N8 canine influenza virus (CIV) in a population of US dogs with influenza-like illness (ILI) and to identify factors associated with seropositivity.

Design—Cross-sectional study.

Animals—1,268 pet and shelter dogs with ILI in 42 states.

Procedures—Serum samples collected from dogs from 2005 through June 2009 were tested for H3N8 CIV antibodies with a hemagglutination inhibition assay. Intrinsic factors (age, breed, and sex), extrinsic factors (dogs housed in a shelter facility, boarding kennel, or other setting), and geographic region (southwest, west, Midwest, southeast, and northeast) were compared between seropositive and seronegative dogs to identify variables associated with seropositivity.

Results—Most (750/1,268 [59%]) dogs in the study were from Colorado, Florida, or New York. The overall seroprevalence of antibodies against H3N8 CIV was 49% (618/1,268 dogs; 95% confidence interval, 46% to 51%). The annual prevalence of H3N8 CIV seropositivity increased from 2005 (44%) to 2006 (53%) and 2007 (62%), then decreased in 2008 (38%) and 2009 (15%). The likelihood of H3N8 CIV seropositivity was associated with geographic region (southeast during 2005, west and northeast during 2006 and 2007, and northeast during 2008) and exposure setting (dogs housed in a shelter facility or boarding kennel during 2005 and 2006).

Conclusions and Clinical Relevance—Results of this study suggested there is a need for continued surveillance for H3N8 CIV infection in dogs in the United States and that personnel in communal dog-housing facilities should formulate, implement, and evaluate biosecurity protocols to reduce the risk of CIV transmission among dogs.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate canarypox-vectored equine influenza virus (EIV) vaccines expressing hemagglutinins of A/equine/Kentucky/94 (vCP1529) and A2/equine/Ohio /03 (vCP2242) for induction of antibody responses against canine influenza virus (CIV) in dogs.

Animals—35 dogs.

Procedures—Dogs were randomly allocated into 4 groups; group 1 (n = 8) and group 2 (9) were inoculated SC on days 0 and 28 with 1.0 mL (approx 105.7 TCID50) of vCP1529 and vCP2242, respectively. Dogs in group 3 (n = 9) were inoculated twice with 0.25 mL (approx 105.7 TCID50) of vCP2242 via the transdermal route. The 9 dogs of group 4 were control animals. All dogs were examined for adverse reactions. Sera, collected on days −1, 7, 13, 21, 28, 35, and 42, were tested by hemagglutination inhibition (HI) and virus neutralization (VN) assays for antibodies against CIV antigens A/Canine/FL/43/04-PR and A/Canine/NY/115809/05, respectively.

Results—Inoculations were tolerated well. The HI and VN antibodies were detected by 7 days after primary inoculation. Most dogs of groups 1 and 2 and all dogs of group 3 had detectable antibodies by 14 days after initial inoculation. The second inoculation induced an anamnestic response, yielding geometric mean HI titers of 139, 276, and 1,505 and VN titers of 335, 937, and 3,288 by day 42 (14 days after booster inoculation) in groups 1, 2, and 3, respectively.

Conclusions and Clinical Relevance—Canarypox-vectored EIV vaccines induce biologically important antibodies and may substantially impact CIV transmission within a community and be of great value in protecting dogs against CIV-induced disease.

Full access
in American Journal of Veterinary Research