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  • Author or Editor: Heather E. Clarke x
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Abstract

Objective—To determine relative detection rates and detection limits for 6 published polymerase chain reaction (PCR) assays used for detection of feline herpesvirus type 1 (FHV-1) DNA.

Sample Population—5 vaccines licensed for use in preventing FHV-1–associated disease; 15 conjunctival biopsy specimens collected from cats with keratitis, conjunctivitis, or both; and a plaque-purified field isolate of FHV-1 cultured in vitro.

Procedure—Vaccines and clinical samples were assessed for FHV-1 DNA by use of all 6 assays. Detection rates were calculated by assuming that any sample in which FHV-1 DNA was detected was a true-positive result. Detection limits were estimated by use of serial dilutions of DNA extracted from cultured FHV-1 and 1 clinical sample.

Results—Testing by use of all 6 assays resulted in detection of FHV-1 DNA in all 5 vaccines. Testing by use of all 6 assays yielded concordant results for 9 of 15 conjunctival biopsy specimens (8 with negative results and 1 with a positive result). Calculated detection rates for clinical samples ranged from 29% to 86%. Assay sensitivity was ranked similarly by use of detection rate or detection limit.

Conclusions and Clinical Relevance—Testing by use of all assays was equally likely to detect vaccine virus. Therefore, a positive PCR result in a cat may reflect vaccine virus rather than wild-type virus. Test sensitivity as assessed by detection limits and detection rates varied greatly. Because FHV-1 can be shed in clinically normal animals, high detection rate will not necessarily correlate with high diagnostic sensitivity. (Am J Vet Res 2005;66:1550–1555)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To establish the in vitro efficacy of 4 novel drugs (ie, ganciclovir, cidofovir, penciclovir, and foscarnet) against feline herpesvirus type-1 (FHV-1) and compare their antiviral efficacy with that of acyclovir and idoxuridine.

Sample Population—Cultured Crandell-Reese feline kidney (CRFK) cells and FHV-1 strain 727.

Procedure—For each drug, antiviral effect was estimated by use of conventional plaque-reduction assays, and inhibitory concentration 50 (IC50; drug concentration at which plaque numbers were reduced by 50% relative to the number of plaques for nontreated control wells) was calculated. To determine whether observed antiviral effects were related to alterations in the number or viability of CRFK cells, cytotoxicity assays were performed at 1, 2, and 10 times the median IC50 for each antiviral drug.

Results—Median IC50 for each drug was as follows: ganciclovir, 5.2µM; cidofovir, 11.0µM; penciclovir, 13.9µM; foscarnet, 232.9µM; idoxuridine, 4.3µM; and acyclovir, 57.9µM. Obvious changes in morphologic characteristics, confluence, or viability of CRFK cells were not observed at concentrations up to and including 2 times the IC50 for each drug.

Conclusions and Clinical Relevance—In vitro efficacy of idoxuridine and ganciclovir against FHV-1 was approximately equivalent and about twice that of cidofovir and penciclovir. Foscarnet appeared to be comparatively ineffective. Given the reasonable clinical efficacy of idoxuridine in cats infected with FHV-1, clinical trials of ganciclovir, cidofovir, and penciclovir or their prodrug forms appear to be warranted. (Am J Vet Res 2004;65:399–403)

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in American Journal of Veterinary Research

Abstract

Objective–To determine detection rates for feline herpesvirus type 1 (FHV-1), Mycoplasma spp, fungi, and bacteria in flush samples and biopsy specimens from the nasal cavities of cats with and without chronic rhinosinusitis (CRS).

Design–Prospective study.

Animals–10 CRS-affected cats and 7 cats without signs of respiratory tract disease.

Procedures–Nasal flush samples and biopsy specimens were collected from all cats for bacterial (aerobic and anaerobic), fungal, and mycoplasmal cultures; additional biopsy specimens were collected for virus isolation and polymerase chain reaction (PCR) assay (to detect FHV-1 DNA).

Results–Aerobic bacteria were detected in flush samples from 5 of 7 control cats; culture of flush samples from CRS-affected cats yielded aerobic bacteria (9/10 cats), anaerobic bacteria (3/10), and Mycoplasma spp (2/10). No fungal organisms were isolated from any cat. Potential pathogens were isolated significantly more often from CRS-affected cats than from control cats. Bacterial culture of biopsy specimens yielded aerobic bacteria (2/7 control cats and 4/10 CRS-affected cats) and anaerobic bacteria (2/10 CRS-affected cats). Although FHV-1 was not detected in nasal biopsy specimens from control or CRS-affected cats, FHV-1 DNA was detected via PCR assay in specimens from 4 of 7 control cats and 3 of 10 CRS-affected cats.

Conclusions and Clinical Relevance–Compared with findings in control cats, anaerobic bacteria, Mycoplasma spp, and a variety of potentially pathogenic organisms were detected more commonly in samples from cats with CRS. In both groups, FHV-1 was detected via PCR assay as a nonviable organism or in noncultivable amounts. (J Am Vet Med Assoc 2005;227:579–585)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To investigate the correlation of cumulative rhinoscopic findings of hyperemia, mucus accumulation, and turbinate destruction with the type and severity of inflammatory infiltrates in nasal biopsy specimens of cats with or without upper respiratory tract disease.

Design—Prospective study.

Animals—Cats with (n = 11) and without (6) upper respiratory tract disease and cats with unknown medical histories (27).

Procedures—Lesions of hyperemia, mucus accumulation, and turbinate destruction detected rhinoscopically were each scored (scale, 0 [absent] to 3 [severe]), and a cumulative rhinoscopic score for each nasal cavity was calculated. Fifty biopsy specimens were examined histologically, and inflammatory infiltrates (lymphoplasmacytic or neutrophilic) were graded as absent, mild, moderate, or severe. Cumulative rhinoscopic scores and inflammation grades were compared for each specimen-cavity combination.

Results—In cats of known disease status, there was a positive but weak correlation between cumulative rhinoscopic scores and inflammation grades in biopsy specimens. In cats of unknown disease status, there was no similar correlation. Biopsy specimens with minimal inflammation were commonly obtained from nasal cavities with low rhinoscopic scores; specimens with moderate or severe inflammatory changes were frequently obtained from cavities that appeared normal rhinoscopically. Type of inflammatory infiltrates was not correlated with rhinoscopic signs of inflammation.

Conclusions and Clinical Relevance—The correlation of rhinoscopic findings with inflammation severity in nasal biopsy specimens (determined histologically) was weak or lacking in cats of known and unknown disease status, respectively. Results indicated that rhinoscopy with biopsy provides more complete evaluation of nasal disease than rhinoscopy alone in cats. ( J Am Vet Med Assoc 2004;225: 395–400)

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in Journal of the American Veterinary Medical Association