Objective—To determine prevalence of Dirofilaria
immitis infection among shelter cats.
Animals—239 cats euthanatized at an animal shelter
in southeastern Michigan.
Procedure—A gross necropsy focusing on the thoracic
cavity, heart, lungs, and pulmonary vessels was
performed within 5 hours after cats were euthanatized.
Blood was collected directly from the heart of
cats found to be infected and tested, using a filter test
for microfilariae. Serum was tested for D immitis antigens
by use of 2 antigen detection kits and for D
immitis-specific antibodies by use of 2 antibody
Results—Cats ranged from approximately 4 months
to 15 years old. Adult D immitis were found in 6
(2.5%) cats. Blood could not be recovered from 1 of
the cats with heartworm infection. For the 5 other
cats, results of the filter test were negative, and
results of both antigen and both antibody tests were
Conclusions and Clinical Relevance—Results suggest
that cats living in an urban area in the northern
part of the United States have a low prevalence of
adult D immitis infection. However, this is likely to be
an underestimate of the true prevalence of infection,
because no attempts were made to identify cats
infected with larval or juvenile stages of D immitis. (J
Am Vet Med Assoc 2000;217:211–212)
Objective—To determine clinical signs, diagnostic findings, tissue tremetone concentrations, and clinical outcome or postmortem findings in horses evaluated for acute severe nonexertional rhabdomyolysis initially attributed to white snakeroot toxicosis.
Design—Retrospective case series.
Procedures—Records of the University of Minnesota Veterinary Medical Center or Diagnostic Laboratory were searched from 1998 to 2005. Inclusion criteria included serum creatine kinase (CK) activity > 45,000 U/L, severe nonexertional myonecrosis of proximal postural muscles at necropsy, or signs of weakness without palpably firm muscles on physical examination. Vitamin E and selenium concentrations were measured in 6 horses; tremetone concentration was measured in 7.
Results—Clinical signs occurred during unfavorable weather conditions. Clinical signs of generalized weakness (n = 11 horses), muscle fasciculations (10), lethargy (6), and prolonged recumbency (4) were common. Serum CK activity ranged from 46,487 to 959,499 U/L (reference range, 82 to 449 U/L), and aspartate transaminase activity was > 1,500 U/L (reference range, 162 to 316 U/L). Two horses survived with aggressive antioxidant and fluid treatment. Postmortem examination revealed acute severe myonecrosis with lipid accumulation primarily in neck, proximal forelimb and hind limb, intercostal, and diaphragm muscles. Histopathologic signs of myocardial necrosis were detected in 7 horses. Vitamin E and selenium concentrations were within reference limits. Tremetone was not detected in liver or urine samples.
Conclusions and Clinical Relevance—Cases of rhabdomyolysis have been attributed to white snakeroot toxicosis; however, tremetone was not detected in any horses. Similarities exist between cases of seasonal pasture myopathy and cases of atypical myopathy in Europe.
Objective—To determine the effect of oral administration
of dantrolene sodium on serum creatine
kinase (CK) activity after exercise in horses with
recurrent exertional rhabdomyolysis (RER).
Animals—2 healthy horses and 5 Thoroughbreds
Procedure—3 horses received 2 doses of dantrolene
(4, 6, or 8 mg/kg, PO, with and without withdrawal of
food) 2 days apart; 90 minutes after dosing, plasma
dantrolene concentration was measured spectrofluorometrically.
On the basis of these results, 5
Thoroughbreds with RER from which food was withheld
received dantrolene (4 mg/kg) or an inert treatment
(water [20 mL]) orally 90 minutes before treadmill
exercise (30 minutes, 5 d/wk) during two 3-week
periods. Serum CK activity was determined 4 hours
after exercise. Plasma dantrolene concentration was
measured before and 90 minutes after dosing on the
first and last days of dantrolene treatment and before
dosing on the first day of the inert treatment period.
Results—90 minutes after dosing, mean ± SEM plasma
dantrolene concentration was 0.62 ± 0.13 and 0
µg/mL in the dantrolene and inert treatment groups,
respectively. Serum CK activity was lower in dantrolene-
treated horses (264 ± 13 U/L), compared with
activity in water-treated horses (1,088 ± 264 U/L). Two
horses displayed marked muscle stiffness on the inert
Conclusions and Clinical Relevance—In 5 horses
with RER from which food had been withheld, 4 mg
of dantrolene/kg administered orally provided measurable,
though variable, plasma concentrations and
significantly decreased serum CK activity after exercise
in 4 of those horses. ( Am J Vet Res 2004;
Objective—To determine the effects of dexamethasone
on development of IgG subclass responses following
vaccination of healthy horses.
Animals—11 mature Thoroughbreds.
Procedure—Horses received 2 IM injections at 2-
week intervals of a vaccine containing inactivated
infectious bovine rhinotracheitis, bovine viral diarrhea,
and parainfluenza-3 viral antigens and were then randomly
assigned to 2 groups. Six horses received dexamethasone
(0.2 mg/kg of body weight, IM) twice
weekly for 8 weeks starting the day of the first vaccination.
Five control horses received an equivalent volume
of saline (0.9% NaCl) solution. Antigen-specific
serum IgG subclass titers were determined weekly
after vaccination by use of an ELISA.
Results—Vaccination resulted in similar antigen-specific
serum IgG(T) titers in dexamethasone-treated
and control horses. In contrast, although control horses
developed IgGa and IgGb responses after vaccination,
corticosteroid administration completely inhibited
these responses in treated horses.
Conclusions and Clinical Relevance—Cortico
steroids can have profound effects on primary
immune responses in horses and can significantly
affect IgG responses to inactivated vaccines.
Corticosteroid treatment regimens commonly used
to treat diseases in horses may result induction of a
nonprotective IgG subclass response, leaving treated
horses susceptible to disease. Additionally, mechanisms
regulating IgGa and IgGb responses appear to
differ from those regulating IgG(T) responses. Further
defining these mechanisms is a critical step in designing
effective vaccines, and corticosteroid-induced
immunomodulation may be a valuable tool for studying
immune responses in horses. (Am J Vet Res
Objective—To compare pharmacokinetics after IV, IM, and oral administration of a single dose of meloxicam to Hispaniolan Amazon parrots (Amazona ventralis).
Animals—11 healthy parrots.
Procedures—Cohorts of 8 of the 11 birds comprised 3 experimental groups for a crossover study. Pharmacokinetics were determined from plasma concentrations measured via high-performance liquid chromatography after IV, IM, and oral administration of meloxicam at a dose of 1 mg/kg.
Results—Initial mean ± SD plasma concentration of 17.3 ± 9.0 μg/mL was measured 5 minutes after IV administration, whereas peak mean concentration was 9.3 ± 1.8 μg/mL 15 minutes after IM administration. At 12 hours after administration, mean plasma concentrations for IV (3.7 ± 2.5 μg/mL) and IM (3.5 ± 2.2 μg/mL) administration were similar. Peak mean plasma concentration (3.5 ± 1.2 μg/mL) was detected 6 hours after oral administration. Absolute systemic bioavailability of meloxicam after IM administration was 100% but was lower after oral administration (range, 49% to 75%). Elimination half-lives after IV, IM, and oral administration were similar (15.9 ± 4.4 hours, 15.1 ± 7.7 hours, and 15.8 ± 8.6 hours, respectively).
Conclusions and Clinical Relevance—Pharmacokinetic data may provide useful information for use of meloxicam in Hispaniolan Amazon parrots. A mean plasma concentration of 3.5 μg/mL would be expected to provide analgesia in Hispaniolan Amazon parrots; however, individual variation may result in some birds having low plasma meloxicam concentrations after IV, IM, or oral administration. After oral administration, meloxicam concentration slowly reached the target plasma concentration, but that concentration was not sustained in most birds.
Case Description—A 4-year-old spayed female mixed-breed dog with a history of allergic skin disease was examined because of regurgitation, coughing, and dysphagia that began 15 days after abdominal surgery for correction of gastric dilatation and volvulus.
Clinical Findings—Severe diffuse esophagitis, esophageal dysmotility, and a benign esophageal stricture at the level of the base of the heart were identified via contrast videofluoroscopy and esophagoscopy. Severe diffuse eosinophilic ulcerative esophagitis was confirmed by histologic examination of esophageal biopsy specimens and cytologic evaluation of specimens obtained by use of a cytology brush. Esophageal eosinophils were evident (14% to 50% of the inflammatory cell population and > 25 eosinophils/hpf).
Treatment and Outcome—No clinical or endoscopic improvement was evident after treatment with antireflux medications, including a proton-pump inhibitor, following an initial esophageal bougienage procedure. An excellent response characterized by resolution of dysphagia and regurgitation with marked improvement of the esophageal mucosa was evident following intralesional and systemic administration of glucocorticoids, 2 additional esophageal bougienage procedures, and feeding of an elimination diet.
Clinical Relevance—To our knowledge, the information reported here is the first description of eosinophilic esophagitis (EE) in a dog. Many similarities exist between the condition in the dog reported here and EE in humans. This clinical report highlights the need to consider EE as a differential diagnosis for esophagitis and esophageal strictures in dogs. When appropriate, esophageal biopsy or cytologic specimens should be obtained and examined to investigate the possibility of EE.