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