Objective—To determine whether monthly topical administration of a combination of 10% imidacloprid and 1% moxidectin would lessen flea (Ctenocephalides felis) transmission of Bartonella henselae among cats.
Animals—18 specific pathogen–free cats housed in 3 groups of 6.
Procedures—3 enclosures were separated by mesh to allow fleas to pass among groups yet prevent cats from contacting one another. One group was inoculated IV with B henselae, and after infection was confirmed, the cats were housed in the middle enclosure. This infected group was flanked by a group that was treated topically with 10% imidacloprid–1% moxidectin monthly for 3 months and by an untreated group. On days 0, 15, 28, and 42, 100 fleas/cat were placed on each of the 6 cats in the B henselae–infected group. Blood samples were collected from all cats weekly for detection of Bartonella spp via PCR assay, bacterial culture, and serologic assay.
Results—B henselae infection was confirmed in the cats infected IV and in all untreated cats after flea exposure; none of the cats treated with the imidacloprid-moxidectin combination became infected.
Conclusions and Clinical Relevance—In this setting, monthly topical administration of 10% imidacloprid–1% moxidectin reduced flea infestation, compared with infestation in untreated cats, and thus prevented flea transmission of B henselae to treated cats. Regular monthly use of this flea control product in cats may lessen the likelihood of humans acquiring B henselae infection.
Objective—To determine regional seroprevalence
estimates of Toxoplasma gondii-specific IgM and IgG
in clinically ill cats throughout the United States.
Sample Population—Sera from 12,628 clinically ill,
Procedure—Toxoplasma gondii-specific IgM and IgG
antibodies were detected by use of ELISAs. Sera
from clinically ill cats previously submitted for T gondii
antibody testing were sequentially selected from our
serum bank and the sample submission paperwork
reviewed. The country was divided into 12 geographic
regions. Overall prevalence as well as prevalence
for each region, age group, season, sex (male vs
female), and breed (domestic shorthair vs other) was
calculated. Data were analyzed by logistic regression
Results—Overall, 31.6% of the cats were seropositive
for T gondii-specific IgM, IgG, or both. Percentage
of cats seropositive for T gondii antibodies ranged
from 16.1% (southwestern United States) to 43.5%
(northeastern United States). As age increased, odds
of positive T gondii antibody assay results (IgM alone,
IgG alone, and any combination of IgM or IgG)
increased. Males were more likely than females to be
seropositive for T gondii antibodies (IgG alone and any
combination of IgM or IgG). Domestic shorthair cats
were more likely than other breeds to be seropositive
for T gondii antibodies (IgM alone, IgG alone, and any
combination of IgM or IgG).
Conclusions and Clinical Relevance—Toxoplasma
gondii-specific antibodies are common in serum samples
of clinically ill cats from all regions of the United
States. Seroprevalence increases as cats age and is
higher in male and domestic shorthair cats, compared
with females and other breeds. (Am J Vet Res 2005;
Objective—To assess efficacy of Giardia vaccination
as a treatment for giardiasis in experimentally infected
Animals—16 young-adult cats.
Procedure—Cats were experimentally infected by
orogastric administration of Giardia cysts. On weeks
4, 6, and 10, cats in the treatment group (n = 8) were
given Giardia vaccine SC. For the first 28 weeks after
infection, 3 fecal samples from each cat were examined
weekly for Giardia cysts, and cyst numbers
were counted. Fecal consistency was scored daily
for the duration of the study. Results from vaccinated
and unvaccinated cats were compared by logistic
Results—All cats became infected and were shedding
Giardia cysts by the end of week 2. Throughout
the study, diarrhea was rare and was mild and transient
when it did occur. By week 28, 5 of 8 vaccinated
cats and 7 of 8 control cats had patent Giardia
infections. Magnitude of infection, based on number
of fecal samples with cysts and number of cysts per
sample, decreased progressively in both groups over
Conclusions and Clinical Relevance—Administration
of 3 doses of a Giardia vaccine did not completely
eliminate the organism from experimentally infected
cats in the study period. Since clinical signs were minimal
in both groups of cats, it could not be determined
whether vaccination lessened severity of clinical disease.
Results may have been negatively influenced by
the large inoculation dose. Whether Giardia vaccination
is an effective treatment for giardiasis in naturally
infected cats remains to be determined. (J Am Vet
Med Assoc 2003;222:1548–1551)
Objective—To determine whether fenbendazole
effectively eliminates Giardia organisms from chronically
infected cats that have a concurrent
Cryptosporidium parvum infection.
Animals—16 clinically normal cats.
Procedure—Eight cats with chronic concurrent
Giardia and C parvum infections received fenbendazole
(50 mg/kg, PO, q 24 h) for 5 days (treatmentgroup
cats). Feces from each cat were collected and
processed 3 days weekly for 23 days after treatment.
By use of an immunofluorescent assay for detection
of Giardia lamblia cysts and C parvum oocysts, organism
numbers were counted and scored. Fecal results
from treatment-group cats were compared with
those of 8 untreated cats with Giardia infection but no
C parvum infection (control-group cats).
Results—Four of 8 treatment-group cats had consistently
negative results for Giardia infection after treatment.
These 4 cats had consistently positive results
for C parvum oocysts prior to treatment and consistently
negative results after treatment. One treatment
-group cat had positive results for cysts on all fecal
samples, and 3 treatment-group cats had 1 to 3 negative
results and then resumed shedding large numbers
of cysts; each of these cats had consistently
positive results for C parvum oocysts. When compared
with control-group cats, treatment-group cats
shed less Giardia cysts during week 1 after treatment
but not during week 2.
Conclusions and Clinical Relevance—Administration
of fenbendazole decreases Giardia cyst shedding to
less than detectable numbers in some cats. In our
study, persistent C parvum infection may have been
associated with failure of fenbendazole to eliminate
Giardia infection. (Am J Vet Res 2003;64:1027–1029)
Objective—To determine whether detection of virusspecific
serum antibodies correlates with resistance
to challenge with virulent feline herpesvirus 1 (FHV-1),
feline calicivirus (FCV), and feline parvovirus (FPV) in
cats and to determine percentages of client-owned
cats with serum antibodies to FHV-1, FCV, and FPV.
Design—Prospective experimental study.
Animals—72 laboratory-reared cats and 276 clientowned
Procedures—Laboratory-reared cats were vaccinated
against FHV-1, FCV, and FPV, using 1 of 3 commercial
vaccines, or maintained as unvaccinated controls.
Between 9 and 36 months after vaccination,
cats were challenged with virulent virus. Recombinant-antigen ELISA for detection of FHV-1-, FCV-,
and FPV-specific antibodies were developed, and
results were compared with results of hemagglutination
inhibition (FPV) and virus neutralization (FHV-1
and FCV) assays and with resistance to viral challenge.
Results—For vaccinated laboratory-reared cats, predictive
values of positive results were 100% for the
FPV and FCV ELISA and 90% for the FHV-1 ELISA.
Results of the FHV-1, FCV, and FPV ELISA were positive
for 195 (70.7%), 255 (92.4%), and 189 (68.5%),
respectively, of the 276 client-owned cats.
Conclusions and Clinical Relevance—Results suggest
that for cats that have been vaccinated, detection
of FHV-1-, FCV-, and FPV-specific antibodies is
predictive of whether cats are susceptible to disease,
regardless of vaccine type or vaccination interval.
Because most client-owned cats had detectable
serum antibodies suggestive of resistance to infection,
use of arbitrary booster vaccination intervals is
likely to lead to unnecessary vaccination of some cats.
(J Am Vet Med Assoc 2002;219:38–42)
Objective—To determine whether Mycoplasma haemofelis (Mhf) and Candidatus Mycoplasma haemominutum (Mhm) can be transmitted by ingestion of Mycoplasma-infected Ctenocephalides felis and by-products (feces, larvae, and eggs).
Procedure—3 cats were carriers of Mhf, and 1 was a carrier of Mhm. Six cats had negative results of PCR assay for Mhf and Mhm DNA. A chamber containing 100 C felis was bandaged to 2 Mhf carrier cats. Five days later, fleas and by-products were analyzed for Mycoplasma spp DNA. The remaining fleas and a sample of by-products were fed to 2 Mycoplasma-naïve cats. A chamber containing 200 C felis was bandaged to the Mhm carrier cat. Five days later, fleas and by-products were analyzed for Mycoplasma spp DNA. The remaining fleas and a sample of by-products were fed to 2 Mycoplasma-naïve cats. A chamber containing 200 C felis was bandaged to an Mhf carrier cat and Mhm-carrier cat. Three days later, fleas and by-products were analyzed for Mycoplasma spp DNA. The remaining fleas and a random sample of by products were fed to 4 Mycoplasma-naïve cats. All cats were monitored for infection for ≥7 weeks.
Results—Uptake of Mhf and Mhm DNA into fleas and by-products was detected. None of the naïve cats became infected.
Conclusions and Clinical Relevance—Results suggested that ingestion of Mycoplasma-infected C felis or by-products is not an important means of transmission for Mhf or Mhm.
Objective—To determine whether Ctenocephalides
felis can transmit Mycoplasma haemofelis (Mhf) and
Candidatus Mycoplasma haemominutum (Mhm)
through hematophagous activity between cats.
Procedure—2 cats were carriers of either Mhf or
Mhm. Nine cats had negative results via polymerase
chain reaction (PCR) assay for Mhf and Mhm DNA; 3
of those cats were infected from the chronic carriers
via IV inoculation of blood. At the time of maximum
organism count for each of the Mycoplasma spp, 1
chamber containing 100 C felis was bandaged to the
amplifier cats. Five days later, fleas, feces, larvae, or
eggs from each chamber were analyzed for
Mycoplasma spp DNA. Viable fleas from the chambers
were allocated into new chambers (3 Mhm and
6 Mhf) and attached to naïve cats for 5 days. Cats
were monitored daily for clinical signs and weekly via
CBC and PCR assay for infection with Mhf or Mhm for
a minimum of 8 weeks.
Results—Uptake of Mhf and Mhm DNA into fleas,
feces, and, potentially, eggs and larvae was detected.
Of the naïve cats fed on by Mhf-infected fleas, 1 cat
transiently yielded positive PCR assay results for Mhf
on 1 sampling date without clinical or hematologic
changes consistent with Mhf infection.
Conclusions and Clinical Relevance—Results suggest
that hematophagous transfer of Mhm and Mhf
into fleas occurred and that C felis is a possible vector
for Mhf via hematophagous activity. (Am J Vet Res 2005;66:1008–1012)
Objective—To develop a polymerase chain reaction
(PCR) assay that detects and differentiates the Ohio
strain of Haemobartonella felis (H felis-OH) and the
California strain of H felis (H felis-CA) and to apply the
assay to blood samples from cats with and without
suspected haemobartonellosis (suspect and control
Sample Population—220 blood samples were
examined; 82 were from suspect cats, and 138 were
from control cats.
Procedure—A PCR assay was designed to detect
and differentiate H felis-OH and H felis-CA.
Results—On the basis of PCR assay results, the overall
prevalence of H felis infection was 19.5% (43/220).
Suspect cats (28.0%; 23/82) were significantly more
likely than control cats (14.5%; 20/138) to be H felis
infected. Significantly greater numbers of suspect
cats were H felis-OH infected (12.2%, 9/82) or H felis-OH and H felis-CA infected (4.9%, 4/82) than control
cats (0% [0/138] and 0.7% [1/138], respectively).
Significantly more anemic cats were H felis-OH infected
(14.3%; 4/28) or H felis-OH and H felis-CA infected
(7.1%; 2/28) than nonanemic cats (2.3% [3/128] and
0.8% [1/128], respectively). The PCR assay was more
accurate than cytologic examination for detection of
Conclusion and Clinical Relevance—
Haemobartonella felis infections are more common in cats
than previously recognized. Haemobartonella felis-OH
is apparently more pathogenic than H felis-CA. The
PCR assay is more accurate than cytologic examination
for detection of H felis infection and is an effective
clinical tool for the detection and differentiation of
both H felis strains known to infect cats. (Am J Vet
Objective—To compare treatment with enrofloxacin
and doxycycline with no treatment in cats experimentally
infected with Haemobartonella felis.
Design—Prospective case-control study.
Procedure—Cats were inoculated with large-form
H felis from a chronically infected donor. Cats were
assigned to 1 of 4 treatment groups: doxycycline
(5 mg/kg [2.3 mg/lb], PO, q 12 h), low-dose
enrofloxacin (5 mg/kg, PO, q 24 h), high-dose
enrofloxacin (10 mg/kg [4.5 mg/lb], PO, q 24 h), and
an untreated control group. Clinical signs, Hct,
blood smears, and a polymerase chain reaction
(PCR) assay were used to monitor progression of
Results—All cats were confirmed to be infected with
H felis via blood smear evaluations and PCR assay
results. Treatment had no effect on Hct during the
intratreatment period, but Hct values were significantly
greater in the low-dose enrofloxacin group,
compared with the control group, during the posttreatment
period. During the intratreatment period, H
felis organism counts per 1,000 RBC in the doxycycline
treatment and the high-dose enrofloxacin treatment
groups decreased at a significantly faster rate
than those in the control group. In the posttreatment
period, organism counts in the doxycycline treatment
group and the low- and high-dose enrofloxacin groups
decreased at significantly faster rates than counts in
the control group. There was no significant effect of
treatment on the number of positive PCR assay
results. Two cats treated with enrofloxacin and 1 cat
treated with doxycycline completely cleared the
H felis organism despite presumed immunosuppression
caused by glucocorticoids.
Conclusions and Clinical Relevance—Results support
the hypothesis that enrofloxacin has anti-H felis
effects. (J Am Vet Med Assoc 2002;221:250–253)
Objective—To evaluate the efficacy of the fluoroquinolone pradofloxacin in the treatment of cats experimentally infected with Mycoplasma hemofelis.
Animals—23 young adult specific-pathogen–free cats.
Procedures—Cats were inoculated with M hemofelis from a chronically infected donor and assigned to 1 of 4 treatment groups: a doxycycline group, a low-dose–pradofloxacin group, a high-dose–pradofloxacin group, and an untreated control group. Treatment was initiated for 14 days when M hemofelis infection was detected via PCR assay and clinical signs of hemoplasmosis were present. Cats that had negative PCR assay results after treatment were administered a glucocorticoid and monitored via PCR assay for an additional 4 weeks.
Results—All cats yielded positive results for M hemofelis via conventional PCR and quantitative PCR assays and developed anemia. The low-dose–pradofloxacin group had significantly lower M hemofelis copy numbers than the doxycycline group. Six cats treated with pradofloxacin yielded negative results during treatment. Of those cats, 4 yielded negative conventional PCR assay results and all yielded negative quantitative PCR assay results for M hemofelis 1 month after administration of high-dose glucocorticoids.
Conclusions and Clinical Relevance—Pradofloxacin had anti–M hemofelis effects similar to those of doxycycline. In addition, pradofloxacin may be more effective at long-term M hemofelis organism clearance than doxycycline.