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  • Author or Editor: P. Cynda Crawford x
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Abstract

Objective—To determine the effect of vaccination against FIV on results of serologic assays for FIV infection.

Design—Prospective clinical trial.

Animals—26 specific-pathogen-free cats, 102 laboratory- reared cats (42 unvaccinated and uninfected, 41 vaccinated and uninfected, and 19 infected with FIV), and 22 client-owned cats infected with FIV.

Procedure—To determine the onset and duration of anti-FIV antibody production in cats following vaccination with a whole-virus vaccine, serum was obtained from the 26 specific-pathogen-free cats prior to vaccination and weekly for 10 weeks, then monthly for 52 weeks, after vaccination; serum was tested for anti-FIV antibodies with lateral flow and microwell plate ELISAs. To determine the diagnostic performance of serologic assays for FIV infection, plasma from uninfected, unvaccinated cats; uninfected, vaccinated cats; and FIV-infected cats was tested for FIV antibodies with the 2 ELISAs, a western blot assay, and an immunofluorescence antibody assay and for FIV antigen with an ELISA.

Results—Anti-FIV antibodies were detected in all 26 vaccinated cats 1 year after vaccination. Sensitivity of the antibody assays for FIV infection was high (98% to 100%). Specificity was high in unvaccinated cats (90% to 100%) but poor in vaccinated cats (0% to 54%). None of the vaccinated or infected cats had detectable FIV antigen in plasma.

Conclusions and Clinical Relevance—Results suggest that vaccination against FIV causes false-positive results for at least 1 year with currently available serologic assays for FIV infection. Negative FIV antibody assay results are highly reliable for detection of uninfected cats, but positive results should be interpreted with caution. (J Am Vet Med Assoc 2004;225:1558–1561)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the prevalence of appendicular osteosarcoma (OSA) in Greyhounds compared with other breeds and identify potential intrinsic risk factors associated with development of OSA.

Design—Retrospective case series.

Animals—179 dogs with primary appendicular OSA.

Procedures—Medical records of dogs in which primary appendicular OSA had been diagnosed between 1996 and 2005 were reviewed. Prevalence and crude odds ratios for OSA were calculated for various breeds by comparison with a reference population of mixedbreed dogs. Age and sex were examined as potential risk factors for the 3 breeds with highest prevalence.

Results—Breed period prevalence of OSA was highest for Greyhounds (21/339 [6.2%]), followed by Rottweilers (51/969 [5.3%]) and Great Danes (13/297 [4.4%]); all 21 Greyhounds with OSA were identified as having retired from racing. Sex was not identified as a risk factor for OSA in these breeds, but in all 3 breeds, risk of OSA increased with age. Greyhounds were significantly older at the time of OSA diagnosis (mean, 9.9 years) than were Rottweilers (8.3 years) and Great Danes (7.8 years). Rottweilers and Great Danes were more likely to have OSA involving the forelimbs than the hind limbs. The most frequent lesion sites for all 3 breeds were the proximal end of the humerus and distal end of the radius. The proximal end of the femur was also a common site for the Greyhounds.

Conclusions and Clinical Relevance—Results of the present study suggested that Greyhounds, Rottweilers, and Great Danes had an increased risk of developing OSA, compared with mixed-breed dogs.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the sensitivity, specificity, and overall diagnostic accuracy of polymerase chain reaction (PCR) assays offered by commercial diagnostic laboratories for diagnosis of FIV infection in cats.

Design—Prospective clinical trial.

Animals—124 cats.

Procedure—Blood was collected from cats that were neither infected with nor vaccinated against FIV, uninfected cats that were vaccinated with a licensed FIV vaccine, and cats experimentally and naturally infected with FIV representing subtypes A, B, and C. Coded blood samples were submitted to 3 laboratories in the United States and Canada offering PCR assays for diagnosis of FIV infection to veterinary practitioners. All laboratories tested fresh blood samples, and 1 laboratory also tested samples submitted as dried blood smears. The FIV infection status in all cats was confirmed by virus isolation. Sensitivity, specificity, and correct results were calculated for each PCR assay.

Results—Sensitivity ranged from 41% to 93%. Specificity ranged from 81% to 100% in unvaccinated cats and 44% to 95% in cats vaccinated against FIV. Correct results were obtained in 58% to 90% of 124 cats tested. All tests misidentified both uninfected and infected cats. False-positive results by all laboratories were higher in cats vaccinated against FIV than in unvaccinated cats, suggesting that vaccination interferes with the performance or interpretation of PCR assays used for diagnosis of FIV infection.

Conclusions and Clinical Relevance—PCR assays used for diagnosis of FIV infection presently marketed to veterinary practitioners in North America vary significantly in diagnostic accuracy and did not resolve the diagnostic dilemma resulting from vaccination of cats against FIV. (J Am Vet Med Assoc 2005;226:1503–1507)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate equine IgG as a treatment for kittens with failure of passive transfer of immunity (FPT).

Animals—13 specific pathogen-free queens and their 77 kittens.

Procedure—Kittens were randomized at birth into 9 treatment groups. One group contained colostrumfed (nursing) kittens; the other groups contained colostrum-deprived kittens that were administered supplemental feline or equine IgG PO or SC during the first 12 hours after birth. Blood samples were collected at serial time points from birth to 56 days of age for determination of serum IgG concentrations. The capacity of equine IgG to opsonize bacteria for phagocytosis by feline neutrophils was determined via flow cytometry.

Results—Kittens that received feline or equine IgG SC had significantly higher serum IgG concentrations than those of kittens that received the supplements PO. In kittens that were administered supplemental IgG SC, serum IgG concentrations were considered adequate for protection against infection. The half-life of IgG in kittens treated with equine IgG was shorter than that in kittens treated with feline IgG. Feline IgG significantly enhanced the phagocytosis of bacteria by feline neutrophils, but equine IgG did not.

Conclusions and Clinical Relevance—Serum concentrations of equine IgG that are considered protective against infection are easily attained in kittens, but the failure of these antibodies to promote bacterial phagocytosis in vitro suggests that equine IgG may be an inappropriate treatment for FPT in kittens. (Am J Vet Res 2003;64:969–975)

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in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine characteristics of free-roaming cats evaluated in a trap-neuter-return program.

Design—Cross-sectional study.

Animals—5,323 free-roaming cats.

Procedure—Data collected included sex, maturity, pregnancy status, number of fetuses per pregnancy, cryptorchidism, and occurrence of complications or euthanasia.

Results—Adult cats represented 85% of the population, and 57% were female. Overall, 19% of adult females were pregnant, and mean litter size was 3.6 fetuses. Pregnancy rate peaked at 36 to 47% of all females evaluated in March and April and decreased to ≤ 4% from October through January. Cryptorchidism was observed in 1.9% of the males; 0.4% of the adult females had pyometra. Only 1.9% of the cats were already neutered. Euthanasia and unexpected death rates were 0.4 and 0.3%, respectively. The most common severe problems encountered included pyometra, neoplasia, surgical complications, diaphragmatic hernia, debilitation, and chronic inflammatory diseases.

Conclusions and Clinical Relevance—Neutering programs for free-roaming cats should include preparations to perform more spays than castrations. Typically, almost half of the female cats trapped during spring will be pregnant. Cryptorchidism is uncommon but is encountered on a consistent basis, so care should be taken to differentiate previous castration from retained testicles. Euthanasia of debilitated cats for humane reasons is rarely necessary, and unexpected deaths occur at a low rate. It is feasible and safe to neuter large numbers of free-roaming cats in large-scale clinics. (J Am Vet Med Assoc 2002;221:1136–1138)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether passive transfer of immunity affects results of diagnostic tests for antibodies against FIV in kittens born to vaccinated queens.

Design—Experimental trial.

Animals—12 specific-pathogen-free queens and their 55 kittens.

Procedure—Queens were vaccinated with a wholevirus FIV vaccine prior to breeding. Serum was obtained from the queens on the day of parturition and from the kittens on days 2 and 7, then weekly until results of tests for antibodies against FIV were negative for 2 consecutive weeks. Milk was collected from the queens daily for the first week and then weekly. Serum and milk were tested for antibodies against FIV with 2 commercial assays.

Results—Antibodies against FIV were detected in serum obtained from the queens on the day of parturition and in the milk throughout lactation. All kittens tested positive for antibodies against FIV at 2 days of age. At 8 weeks of age, 30 (55%) kittens tested positive with 1 of the commercial assays, and 35 (64%) tested positive with the other. All kittens tested negative for antibodies against FIV by 12 weeks of age.

Conclusions and Clinical Relevance—Results suggest that kittens readily absorb antibodies against FIV in colostrum from vaccinated queens and that these antibodies may interfere with results of commercially available tests for FIV infection past the age of weaning. Currently licensed diagnostic tests for FIV infection are unable to distinguish among kittens with antibodies against FIV as a result of infection, passive transfer from infected queens, and passive transfer from vaccinated queens. (J Am Vet Med Assoc 2004;225:1554–1557)

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in Journal of the American Veterinary Medical Association

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.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To identify surrogate markers of passive transfer of immunity in kittens.

Design—Prospective clinical trial.

Animals—55 kittens from 12 specific-pathogen–free queens.

Procedure—Kittens were allocated at birth into colostrum-fed (n = 27) and colostrum-deprived (28) groups. Blood was collected at birth and on days 1, 2, 4, 7, 14, 28, and 56. Serum samples were analyzed for activities of alkaline phosphatase (ALP), alanine aminotransferase, aspartate aminotransferase, creatine kinase, lactate dehydrogenase, γ-glutamyltransferase, amylase, and lipase and for concentrations of albumin, total protein, bilirubin, urea nitrogen, creatinine, cholesterol, glucose, calcium, phosphorus, and triglycerides by use of an automated analyzer. Total serum solids concentrations were estimated by use of refractometry. Serum IgG concentrations were quantified by use of radial immunodiffusion.

Results—All kittens were agammaglobulinemic at birth. Colostrum-fed kittens had significantly higher IgG concentrations than did colostrum-deprived kittens from 1 though 28 days of age. Transient significant differences in serum biochemical variables between the colostrum-deprived and colostrum-fed groups were substantially resolved by day 4. Passive transfer of immunity could be reliably determined at 1 day of age and to a lesser extent at 2 days of age only by measurement of serum activity of ALP.

Conclusions and Clinical Relevance—Adequacy of passive transfer in kittens initially correlated with serum activity of ALP, but quantification of serum IgG concentration was necessary after 2 days of age.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare castration of dogs by use of intratesticular injection of zinc gluconate with traditional surgical procedures in terms of acceptance by pet owners, ease of use, and short-term outcomes on Isabela Island of the Galápagos Islands.

Animals—161 privately owned male dogs admitted to a neuter program.

Procedures—Medical records of male dogs neutered during a 4-week animal control campaign were reviewed to collect information regarding signalment, method of castration, complication rate, and treatment outcomes.

Results—Of the 161 dogs admitted for castration, 58 were surgically castrated and 103 were treated with zinc gluconate. Dogs were returned to their owners for observation following castration. Wound dehiscence occurred in 2 skin incisions, representing 3.4% of the 58 dogs that underwent bilateral orchiectomy. Necrotizing zinc-gluconate injection-site reactions occurred in 4 dogs receiving injection volumes near the maximum label dose (0.8 to 1.0 mL), representing 3.9% of the zinc-gluconate procedures. Surgical wound complications were treated by superficial wound debridement and resuturing, in contrast to zinc-gluconate injection-site reactions, which all required orchiectomy and extensive surgical debridement, including scrotal ablation in 2 dogs.

Conclusions and Clinical Relevance—Low cost, ease of use, and cultural acceptance of a castration technique that does not require removal of the testes make zinc gluconate a valuable option for large-scale use in dogs, particularly in remote locations lacking sophisticated clinical facilities or skilled surgeons and staff. Further investigation is needed to identify risk factors in dogs for adverse reactions to zinc gluconate and to develop strategies for avoidance.

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in American Journal of Veterinary Research