Objective—To characterize clinical and hematologic
responses in dogs following experimental inoculation
with Babesia gibsoni-like isolates from infected dogs
Animals—6 mixed-breed dogs.
Procedure—2 dogs were inoculated with organisms
from a naturally infected dog, and 3 were inoculated
with organisms from a second naturally infected dog
(1 of these 3 dogs was splenectomized 1 week prior
to inoculation). One dog was not inoculated.
Complete blood counts were performed weekly.
Results—In the 5 dogs inoculated with organisms,
parasites were initially detected 1 to 5 weeks after
inoculation, and severity of parasitemia peaked with
1.9 to 6.0% of RBC infected by 4 to 6 weeks after
inoculation. Parasitemia was easily detectable
(> 0.1% of RBC infected) for 3 to 4 weeks. Clinical
abnormalities included lethargy, fever, and pale
mucous membranes but were mild to nearly inapparent
in 2 dogs. All dogs developed regenerative anemia
and marked thrombocytopenia. Thrombocytopenia
developed before and lasted longer than the parasitemia.
Profound but transient neutropenia was
detected in some dogs. The splenectomized dog
developed more severe parasitemia and anemia and
more pronounced clinical abnormalities. Three dogs
with intact spleens recovered without treatment.
Conclusions and Clinical Relevance—Results suggest
that 2 or more genotypically distinct, but morphologically
identical, small Babesia parasites can
infect dogs in the United States. Compared with infection
with small Babesia parasites from California,
infection with these isolates resulted in less severe
parasitemia and clinical abnormalities. Parasitemia
was transient, indicating that identification of organisms
in blood smears may be difficult in some dogs.
(J Am Vet Med Assoc 2002;220:185–189)
Objective—To quantitatively determine echogenicity
of the liver and renal cortex in clinically normal cats.
Animals—17 clinically normal adult cats.
Procedure—3 ultrasonographic images of the liver and
the right kidney were digitized from video output from
each cat. Without changing the ultrasound machine
settings, an image of a tissue-equivalent phantom was
digitized. Biopsy specimens of the right renal cortex
and liver were obtained for histologic examination.
Mean pixel intensities within the region of interest
(ROI) on hepatic, renal cortical, and tissue-equivalent
phantom ultrasonographic images were determined by
histogram analysis. From ultrasonographic images,
mean pixel intensities for hepatic and renal cortical ROI
were standardized by dividing each mean value by the
mean pixel intensity from the tissue-equivalent phantom.
Results—The mean (± SD) standardized hepatic
echogenicity value was 1.06 ± 0.02 (95% confidence
interval, 1.02 to 1.10). The mean standardized right
renal cortical echogenicity value was 1.04 ± 0.02
(95% confidence interval, 1.01 to 1.08). The mean
combined standardized hepatic and renal cortical
echogenicity value was 1.02 ± 0.05 (95% confidence
interval, 0.99 to 1.04).
Conclusions and Clinical Relevance—Quantitative
determination of hepatic and renal cortical echogenicity
in cats is feasible, using histogram analysis, and
may be useful for early detection of diffuse parenchymal
disease and for serially evaluating disease progression.
(Am J Vet Res 2000;61:1016–1020)
Objective—To determine effects of exercise performed while breathing cold air on expression of cytokines and influx of neutrophils in airways of horses.
Animals—9 adult horses.
Procedures—In a crossover study, bronchoalveolar lavage fluid (BALF) was obtained 24 and 48 hours after each of 2 submaximal exercise sessions performed by horses while breathing warm (25°C) or cold (−5°C) air. Total and differential nucleated cell counts were determined for each BALF sample. Relative mRNA expression of cytokines in BALF cells was quantified by use of a reverse transcription–PCR assay.
Results—Horses had a modest but significant influx of neutrophils into the airways 24 hours after a single exercise session while breathing cold air. No other cell types were increased at 24 or 48 hours after exercising while breathing cold air. Continued increases in expression of cytokines interleukin (IL)-5 and-10 as well as proinflammatory cytokines IL-1, -6, and -8 were detected 24 hours after exercising while breathing cold air. Forty-eight hours after exercising while breathing cold air, expression of IL-10 was still higher than that for IL-10 after horses exercised while breathing warm air. Expression of tumor necrosis factor-α was significantly increased at 48 hours after exercising while breathing cold air.
Conclusions and Clinical Relevance—Exposure of intrapulmonary airways to cold air alters immunologic responses of horses for at least 48 hours. The increased expression of cytokines that suppress cell-mediated immunity may predispose athletes to viral infections of the respiratory tract following exercise in cold weather.
Objective—To determine the prevalence of Babesia gibsoni infection in dogs that were confiscated from dogfighting operations.
Animals—157 pit bull–type dogs that were confiscated as part of dogfighting prosecution cases in Iowa, Michigan, Mississippi, Ohio, Pennsylvania, Virginia, and Washington and 218 randomly selected animal shelter dogs with no known history of dogfighting.
Procedures—Blood samples collected from confiscated dogs were tested for infection with B gibsoni by use of a nested PCR assay. Samples that yielded positive results underwent DNA sequencing to confirm infection with B gibsoni. Control blood samples collected from 218 randomly selected dogs in animal shelters (ie, dogs that had no known involvement in dogfighting events) were also analyzed.
Results—Results of nested PCR assays indicated that 53 of 157 (33.8%) confiscated dogs were infected with B gibsoni; 1 (0.6%) dog was infected with the canine small Babesia ‘Spanish isolate’ (also known as Theileria annae). To the authors' knowledge, this is the first report of infection with this small Babesia ‘Spanish isolate’ in a North American dog. Dogs with scars (indicative of fighting) on the face, head, and forelimbs were 5.5 times as likely to be infected with B gibsoni as were dogs without scars. Of the control dogs, 1 (0.5%) pit bull–type dog was infected with B gibsoni.
Conclusions and Clinical Relevance—Results indicated that B gibsoni is a common parasite of dogs confiscated from dogfighting operations and suggested that dogs with a history of fighting should be evaluated for infection with B gibsoni.
Objective—To determine whether antemortem core needle biopsy and fine-needle aspiration of enlarged peripheral lymph nodes could be used to distinguish between inflammation and lymphosarcoma in cattle.
Animals—25 cattle with enlarged peripheral lymph nodes.
Procedures—Antemortem biopsies of the selected lymph nodes were performed with an 18-gauge, 12-cm core needle biopsy instrument. Fine-needle aspirates were performed with a 20-gauge, 4-cm needle. Specimens were analyzed by pathologists who were unaware of clinical findings and final necropsy findings, and specimens were categorized as reactive, neoplastic, or nondiagnostic for comparison with necropsy results.
Results—Sensitivity and specificity of core needle biopsy ranged from 38% to 67% and from 80% to 25%, respectively. Sensitivity of fine-needle aspiration ranged from 41% to 53%, and specificity was 100%. Predictive values for positive test results ranged from 77% to 89% for core needle biopsy and were 100% for fine-needle aspiration. Predictive values for negative test results were low for both core needle biopsy and fine-needle aspiration.
Conclusions and Clinical Relevance—Results indicated that core needle biopsy and fineneedle aspiration can aid in the antemortem diagnosis of bovine enzootic lymphosarcoma. Results of fine-needle aspiration of enlarged peripheral lymph nodes were more specific and more predictive for a positive test result than were results of core needle biopsy.
OBJECTIVE To determine whether prophylactic administration of valacyclovir hydrochloride versus initiation of treatment at the onset of fever would differentially protect horses from viral replication and clinical disease attributable to equine herpesvirus type-1 (EHV-1) infection.
ANIMALS 18 aged mares.
PROCEDURES Horses were randomly assigned to receive an oral placebo (control), treatment at detection of fever, or prophylactic treatment (initiated 1 day prior to viral challenge) and then inoculated intranasally with a neuropathogenic strain of EHV-1. Placebo or valacyclovir was administered orally for 7 or 14 days after EHV-1 inoculation or detection of fever (3 horses/group). Effects of treatment on viral replication and clinical disease were evaluated. Plasma acyclovir concentrations and viremia were assessed to determine inhibitory concentrations of valacyclovir.
RESULTS Valacyclovir administration decreased shedding of virus and viremia, compared with findings for control horses. Rectal temperatures and clinical disease scores in horses that received valacyclovir prophylactically for 2 weeks were lower than those in control horses. The severity of but not the risk for ataxia was decreased by valacyclovir administration. Viremia was decreased when steady-state trough plasma acyclovir concentrations were > 0.8 μg/mL, supporting the time-dependent activity of acyclovir.
CONCLUSIONS AND CLINICAL RELEVANCE Valacyclovir treatment significantly decreased viral replication and signs of disease in EHV-1–infected horses; effects were greatest when treatment was initiated before viral inoculation, but treatment was also effective when initiated as late as 2 days after inoculation. During an outbreak of equine herpesvirus myeloencephalopathy, antiviral treatment may be initiated in horses at various stages of infection, including horses that have not yet developed signs of viral disease.