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

Abstract

Objective—To compare the recovery rates of Campylobacter fetus subsp venerealis (Cfv) from preputial scrapings of infected bulls with passive filtration on selective medium versus nonselective medium, with and without transport medium.

Samples—217 preputial scrapings from 12 bulls (4 naturally and 8 artificially infected with Cfv).

Procedures—Preputial scrapings were collected in 2 mL of PBS solution and bacteriologically cultured directly on Skirrow medium or passively filtered through 0.65-μm filters onto blood agar, with or without 24 hour preincubation in modified Weybridge transport enrichment medium (TEM). After 72 hours, plates were examined for Cfv and bacterial and fungal contamination or overgrowth.

Results—Passive filtration of fresh preputial scrapings onto blood agar yielded significantly higher recovery rates of Cfv (86%) than direct plating on Skirrow medium (32%), whereas recovery from TEM was poor for both media (35% and 40%, respectively). Skirrow cultures without TEM were significantly more likely to have fungal contamination than were cultures performed with any other technique, and fungal contamination was virtually eliminated by passive filtration onto blood agar. Bacterial contamination by Pseudomonas spp was significantly more common with Skirrow medium versus passive filtration on blood agar, regardless of TEM use.

Conclusions and Clinical Relevance—The use of transport medium and the choice of culture medium had significant effects on Cfv recovery and culture contamination rates from clinical samples. Both factors should be considered when animals are tested for this pathogen.

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in American Journal of Veterinary Research

Abstract

Objective—To determine clinical sensitivity and specificity of a quantitative real-time PCR (qRT-PCR) assay for Campylobacter fetus subsp venerealis (Cfv) in preputial samples of bulls.

Animals—313 beef bulls.

Procedures—Preputial samples were collected from 300 virgin bulls and 13 Cfv-infected bulls. Specificity of the qRT-PCR assay, determined on the basis of results for samples collected from virgin bulls, was compared with specificity of bacteriologic culture performed with transport enrichment medium (TEM). Sensitivity of the qRT-PCR assay, determined on the basis of results for multiple samples collected at weekly intervals from infected bulls, was compared with sensitivity of the direct fluorescent antibody test (DFAT), bacteriologic culture, and bacteriologic culture with TEM.

Results—Specificity was 85% for the qRT-PCR assay and 100% for bacteriologic culture; results were significantly different. Mean sensitivity was 85.4% for the qRT-PCR assay, 82.3% for direct culture in blood agar, 72.1% for the DFAT, 32.7% for direct culture in Skirrow agar, 30% for bacteriologic culture with TEM and blood agar, and 38.1% for bacteriologic culture with TEM and Skirrow agar. Differences in sensitivity among tests varied with ambient outdoor temperature. Repeated sampling significantly increased sensitivity of the qRT-PCR assay.

Conclusions and Clinical Relevance—Use of the qRT-PCR assay as a screening test on direct preputial samples had comparable sensitivity to bacteriologic culture, and repeated sampling improved sensitivity. Although improved performance of the qRT-PCR assay, compared with direct bacteriologic culture, was dependent on temperature, transport times that allow direct culture are unlikely under field conditions. The qRT-PCR assay would provide a fast and sensitive screening method for Cfv in bulls.

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in American Journal of Veterinary Research

Abstract

Objective—To determine the sensitivity of a real-time PCR assay for the detection of Tritrichomonas foetus in protozoal cultures of preputial scraping samples pooled from up to 25 bulls and to determine the specificity of that assay for detection of T foetus in cultures for individual animals.

Design—Cross-sectional study.

Animals—188 bulls and 150 steers.

Procedures—Preputial scraping samples were collected, placed in a culture kit, and incubated at 37°C for 7 days. Cultures for individual animals were tested for T foetus by means of a real-time PCR assay. Pools of protozoal cultures were made by including fixed aliquots of samples with known positive and negative results in ratios of 1:2, 1:3, 1:5, 1:10, 1:15, 1:20, and 1:25. Specificities of the real-time PCR assay and culture for detection of T foetus in samples obtained from individual animals and sensitivity of real-time PCR assay for each evaluated pool ratio were determined.

Results—Specificity estimates for culture and the real-time PCR assay for detection of T foetus in preputial scraping samples for individual animals were not significantly different (98.8% and 100%, respectively). Sensitivities of the real-time PCR assay for the various pooled samples with known positive and negative T foetus results were not significantly different; overall sensitivity of the assay was 94%.

Conclusions and Clinical Relevance—Results indicated the evaluated real-time PCR assay had high specificity and good sensitivity for the detection of T foetus in pooled protozoal cultures of preputial scraping samples obtained from up to 25 animals.

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine prevalence of enteric zoonotic organisms in cats in north-central Colorado.

Design—Prospective study.

Sample Population—Serum and fecal samples from 87 cats with diarrhea, 106 cats without diarrhea, and 12 cats for which fecal consistency was unknown.

Procedures—Samples were obtained from clientowned cats and cats at a humane society shelter. Serum was assayed for feline leukemia virus antigen and antibodies against feline immunodeficiency virus, IgM antibodies against Toxoplasma gondii, and IgG antibodies against T gondii and Cryptosporidium parvum. Microscopic examination of unstained feces was performed after centrifugation in a zinc sulfate solution, thin fecal smears were stained with acid fast stain and examined for C parvum, and bacteriologic culture of feces was used to detect aerobic and anaerobic bacteria.

Results—Enteric zoonotic organisms were detected in feces from 27 of 206 (13.1%) cats and included C parvum (5.4%), Giardia spp (2.4%), Toxocara cati (3.9%), Salmonella enterica serotype Typhimurium (1.0%), and Campylobacter jejuni (1.0%); each organism was detected in samples from cats with and without diarrhea. Although differences between groups were not significant, a higher proportion of shelter cats (18.2%) had enteric zoonotic organisms than client-owned cats (10.1%).

Conclusions and Clinical Relevance—Enteric zoonotic organisms were detected in feces of 13.1% of cats, suggesting that cats, particularly those in homes of immunocompromised humans, should be evaluated for enteric zoonotic organisms. (J Am Vet Med Assoc 2000;216:687–692)

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in Journal of the American Veterinary Medical Association

SUMMARY

Intraocular production of Toxoplasma gondii-specific antibody in cats has been estimated by comparing the ratio of T gondii-specific antibody in aqueous humor and serum with the ratio of total immunoglobulins in serum and aqueous humor (Goldmann-Witmer coefficient; aqueous antibody coefficient; C value). It has been proposed that in human beings, comparison of the ratio of T gondii-specific antibody in aqueous humor and serum with the ratio of antibodies against a nonocular pathogen in serum and aqueous humor is more accurate than methods using total immunoglobulin quantification. We developed an elisa for detection of calicivirus-specific antibodies in the serum and aqueous humor of cats. By evaluating calicivirus-specific antibody concentrations in the aqueous humor of healthy and diseased cats, calicivirus was assessed as a nonintraocular pathogen. The ratio of T gondii-specific antibodies in the aqueous humor and serum and the ratio of calicivirus-specific antibodies in serum and aqueous humor were evaluated as a means of estimating intraocular T gondii-specific antibody production.

A field strain of feline calicivirus was isolated, cultured, and purified. A calicivirus-specific IgG elisa was developed for detection of feline calicivirus-specific IgG in serum and aqueous humor. Calicivirus-specific IgG was measured in the serum and aqueous humor from 3 groups of control cats. Results suggested that calicivirus is a nonintraocular pathogen in cats and that calicivirus IgG detected in aqueous humor is attributable to leakage across a damaged blood-ocular barrier.

Intraocular production of T gondii-specific antibodies was estimated, using 2 formulas. The C value was calculated by multiplying the ratio of T gondii-specific IgM or IgG in aqueous humor and serum by the ratio of total immunoglobulins (using the corresponding IgM or IgG class) in serum and aqueous humor. The C tc value (Toxoplasma-calicivirus Goldmann-Witmer coefficient) was calculated by multiplying the ratio of T gondii-specific IgM or IgG in aqueous humor and serum by the ratio of calicivirus-specific IgG in serum and aqueous humor.

Serum and aqueous humor samples were obtained from 41 client-owned cats with uveitis, and T gondii-specific C values and Ctc values were calculated. Toxoplasma gondii-specific IgM or IgG C values of 10 or greater or T gondii-specific IgM or IgG Ctc values of 1 or greater were considered to be suggestive of intraocular T gondii-specific antibody production. Of the 41 cats, 20 (48.7%) had evidence of intraocular production of T gondii-specific antibody on the basis of either an IgM or IgG C value of 10 or greater. A Ctc value could not be calculated in 3 cats because calicivirus-specific IgG was not present in aqueous humor. Of the 38 cats for which Ctc values could be calculated, 25 (65.8 %) had evidence of intraocular production of T gondii-specific antibody on the basis of either an IgM or IgG Ctc value of 1 or greater. The C values and Ctc values were in agreement for 75.9 % of IgM containing samples and 75% of IgG containing samples. Sensitivity, specificity, predictive value of a positive test result, and predictive value of a negative test result for an IgM or IgG C value, when compared with the corresponding IgM or IgG Ctc value were determined. The results indicate that use of the C value for estimation of intraocular T gondii-specific antibody production will result in 28.6 (IgM) to 50 % (IgG) false-negative results and 12.5% (IgM and IgG) false-positive results, when compared with the Ctc value.

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in American Journal of Veterinary Research