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E B Breitschwerdt

Publications and source records attributed to E B Breitschwerdt.

At least 19 recordsLinked to original sources

Evaluation of the pathogenic potential of Rickettsia canada and Rickettsia prowazekii organisms in dogs.

An unusual pattern of seroreactivity to antigens of rickettsial organisms (Rickettsia rickettsii, R rhipicephali, R montana, and R bellii), particularly to R bellii antigen, was detected in 3 dogs during a 2-month period. Thus, studies were initiated to clarify the pathogenic potential of the more distantly related rickettsial organisms (R canada and R prowazekii) in dogs. Because R bellii are nonpathogenic rickettsiae that share numerous common properties with spotted fever-group and typhus-group rickettsiae, and because closely related pathogenic relatives of R bellii have not been identified, we examined the pathogenic potential of these typhus-group rickettsiae by testing stored serum samples, by attempting rickettsial isolation from febrile dogs, and by experimentally inoculating dogs with R canada and R prowazekii. Evaluation of results of a serosurvey of acute and convalescent serum samples from 80 dogs in which Rocky Mountain spotted fever had been considered as a differential diagnosis, but seroconversion to R rickettsii had not been documented, identified 1 dog with a fourfold increase in antibody titer to R rhipicephali and 3 dogs with fourfold increases in antibody titer to 1 or more antigens of typhus-group rickettsial organisms. A study of 15 dogs that were febrile during summer months failed to identify serologic or tissue culture evidence of typhus-group rickettsial infection or typhus-group rickettsemia, but did result in isolation of R rickettsii and Ehrlichia canis, respectively, from 1 dog each. In our final study, after experimentally inoculating 6 dogs with R canada and R prowazekii, all dogs seroconverted to the respective rickettsiae, but rickettsemia or clinical and hematologic evidence of disease was not observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Bartonellosis.

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Animals

Erythrocyte fragility and chronic intermittent pigmenturia in a dog.

A 2-year-old spayed female Shetland Sheepdog had recurrent episodes of discolored urine. Treatments administered for presumed urinary tract infection did not prevent recurrence. Episodes of pigmenturia appeared to correlate with stressful situations or excessive activity. Examination of urine sediment consistently revealed that RBC were not evident, despite a positive result for blood on urinalysis. This was suggestive of hemoglobinuria, and diagnostic testing was instituted to determine the underlying cause. Results of alkaline and osmotic fragility tests were useful in determining that an increase in erythrocyte fragility was the underlying cause of the recurrent pigmenturia. Erythrocyte fragility testing should be considered in animals that do not respond to appropriate treatments for pigmenturia.

Animals

Endocarditis in a dog due to infection with a novel Bartonella subspecies.

Vegetative valvular endocarditis involving the aortic and, to a lesser extent, mitral valves was diagnosed echocardiographically in a 3-year-old spayed female Labrador retriever. Historically, the dog had been treated with tetracycline hydrochloride and prednisolone for positive seroreactivity to Ehrlichia canis and antinuclear antigens. Although three aerobic and anaerobic blood cultures failed to grow bacteria, blood cultured simultaneously by the lysis centrifugation technique grew a fastidious, gram-negative organism. Despite an initial therapeutic response, the owner elected euthanasia 17 days later. Necropsy confirmed aortic and mitral valvular endocarditis. Bacteria phenotypically similar to Bartonella species were visualized in the heart valve by light and electron microscopy, and Bartonella DNA from a frozen heart valve was amplified by PCR. Subsequent phenotypic and genotypic characterization of the isolate, including biochemical testing, cellular fatty acid analysis, DNA hybridization, and sequencing of the 16S rRNA gene indicated that this organism, which can induce endocarditis in dogs, is a novel Bartonella subspecies containing an insertion sequence unique among currently recognized Bartonella species. The name Bartonella vinsonii subsp. berkoffii subsp. nov. will be proposed for this organism.

Animals

Intraerythrocytic presence of Bartonella henselae.

Recent reports in the medical literature emphasize the risk of zoonotic disease and the high degree of prevalence of asymptomatic feline infection with Bartonella (Rochalimaea) henselae. While investigating Bartonella bacteremia in cats, we used transmission electron microscopy to demonstrate B. henselae in the erythrocytes of persistently bacteremic cats.

Animals

Canine mitochondrial myopathy associated with reduced mitochondrial mRNA and altered cytochrome c oxidase activities in fibroblasts and skeletal muscle.

Skeletal muscle and fibroblast biopsies obtained from a normal dog and an old English sheep dog with exertional myopathy and lactic acidosis were examined for mitochondrial enzyme activities and mitochondrially coded mRNAs. The fibroblast cultures of the affected dog showed reduced cytochrome c oxidase (COX) I+II mRNA content (25% of control) and COX enzyme activities (23% of control). The skeletal muscle of the affected dog was similarly affected and showed not only decreased COX I+II mRNA content, but also decreased ATPase6 mRNA level. Apart from COX enzyme activity (62% of control), the oligomycin sensitive ATPase and NADH-Ferricyanide reductase activities were also reduced in the skeletal muscle of the affected dog (12-20% of control). These results suggest that a mitochondrial dysfunction may be the causative factor of the exertional metabolic myopathy with lactic acidosis in this affected old English sheep dog. These animals may serve as an excellent model for mitochondrial myopathies.

Adenosine Triphosphatases

Natural infections with Borrelia spirochetes in two dogs from Florida.

Spirochetemia is a rarely reported observation in dogs. We describe the clinical, hematologic, and immunodiagnostic features of two spirochetemic dogs from northern Florida and the subsequent isolation and preliminary characterization of a Borrelia species from one dog in which culture of a sample for spirochetes was attempted. Results of polyacrylamide gel electrophoresis, monoclonal antibody testing, and PCR analysis indicate that the Florida isolate is not Borrelia burgdorferi, the only other member of the genus that has been isolated in Florida. Our findings also indicate that a member of the genus Borrelia potentially causes disease in dogs in Florida and that serologic cross-reactivity of the Florida canine Borrelia isolate with B. burgdorferi probably contributes to the inaccurate diagnosis of canine Lyme disease in the region.

Animals

The use of a polymerase chain reaction as a diagnostic test for Rocky Mountain spotted fever.

A polymerase chain reaction (PCR) for amplifying ribosomal DNA of Rickettsia rickettsii was performed on blood clots and urine samples from 10 patients with suspected Rocky Mountain spotted fever (RMSF) and five controls with nonrickettsial diseases. The results of this PCR-based procedure were positive in four of the five patients with probable RMSF, but reamplification was required in three patients. Rickettsia rickettsii was grown from the blood of two of these four patients. The urine from one patient was also PCR-positive. These results confirm earlier findings that the PCR can detect R. rickettsii, but the need for reamplification indicates that the lack of sensitivity is a serious limitation in the usefulness of the PCR as a clinical diagnostic test.

Bacteremia

Episodic weakness associated with exertional lactic acidosis and myopathy in Old English sheepdog littermates.

Two Old English Sheepdog littermates were evaluated for weakness that developed during periods of minimally intense exercise. Lactic acidosis accompanied by increased muscle enzyme activity, an increased lactate/pyruvate ratio, and increased venous PO2 supported the possibility of defective mitochondrial oxygen use. Electromyographic abnormalities included increased insertional activity and complex repetitive discharges. Muscle alterations included scattered myofiber necrosis, abundant endomysial connective tissue, excessive glycogen accumulation, and greater than normal numbers and vacuolation of mitochondria. A distinctive pattern of subsarcolemmal mitochondrial aggregates, referred to as "ragged red fibers" in human mitochondrial myopathies, was observed in muscle biopsy samples from 1 dog. Several features of the disease in these dogs, including onset of weakness during early life, simultaneous disease in littermates, subtle nonprogressive weakness of at least 3 years' duration, and partial reversibility of lactic acidosis following rest were suggestive of an inborn error of metabolism, consistent with mitochondrial myopathy.

Acid-Base Equilibrium

Seroprevalence of babesiosis in Greyhounds in Florida.

An indirect fluorescent antibody test was used to serologically survey Greyhounds from 10 kennels that are part of the racing Greyhound industry in Florida. Age of dogs ranged from 11 months to 11 years. Additionally, 50 adult non-Greyhound pet dogs were consecutively surveyed. Of 393 Greyhounds tested, 181 (46%) were seropositive for babesiosis; pet dogs were seronegative. Slightly higher percentage of seropositive males than females was observed, but this difference was only significant (P less than 0.01) in the 2- to 5-year age class. Male dogs less than 2 years old had significantly (P less than 0.01) lower seroprevalence than did male dogs greater than 2 years old. All 46 Greyhounds that were actively racing at the time of sample collection were seronegative. Dogs were classified into 2 groups on the basis of whether the kennel owner had sought veterinary attention for anemic pups. The 5 kennel owners that had sought veterinary attention (group A) had significantly (P less than 0.01) higher seroprevalence (78.5%), compared with the 5 that had not sought veterinary attention (group B; 23.0%). Seroprevalence of babesiosis in Greyhounds in Florida was comparable to that reported in a limited survey of other southeastern states. It appears to be higher than that in the pet population. Breeding kennels in Florida and other southeastern states from which anemic pups originate should be screened for babesiosis.

Age Factors

Effects of dietary protein source on Basenjis with immunoproliferative enteropathy.

The effects of 3 experimental diets that varied only in the source of dietary protein (ie, poultry, cereal, red meat) were compared in Basenjis (n = 8) with immunoproliferative enteropathy and healthy Beagles (n = 8). Significant differences in fecal character, serum IgA concentration, and intestinal digestive and absorptive function were not induced by the different sources of dietary protein. The results of this study do not support a causal role for dietary protein source in the pathogenesis of immunoproliferative enteropathy of Basenjis.

Animal Feed

Acute blindness associated with intracranial tumors in dogs and cats: eight cases (1984-1989).

Rostral and middle cranial fossa tumors affecting the optic chiasm and resulting in acute visual deficits were diagnosed in 7 dogs and 1 cat. Blindness and dilated nonresponsive pupils were the primary signs in all animals. Other concurrent neurologic deficits were either absent or were equivocal. Behavioral changes, including signs of depression and lethargy, were noticed in 1 dog and the cat subsequent to the onset of blindness. Retinal function was assessed as normal by electroretinography in all animals. The histologic necropsy diagnosis was pituitary carcinoma in 1 dog and the cat and paranasal sinus carcinoma with intracranial extension in 1 dog. A cytologic diagnosis of polycentric lymphosarcoma affecting the optic chiasm was diagnosed in 1 dog. In the remaining 4 dogs, results of computed tomographic imaging or endocrine function testing suggested pituitary gland neoplasia. Four dogs were treated with cobalt-60 radiation or chemotherapy. There was partial return of visual function in only 1 of the dogs treated with radiation.

Acute Disease

Bone marrow hypoplasia in a cat treated with griseofulvin.

Three weeks after initiation of griseofulvin treatment for dermatophytosis (40 mg/kg of body weight, q 12 h), an 8-yr-old domestic shorthair cat developed depression, vomiting, and pyrexia. Abnormalities found during physical examination included bilateral mydriasis, visual impairment, grade-II/V systolic murmur and multiple areas of alopecia. The cat was pancytopenic; serum biochemical abnormalities included hyperbilirubinemia, hyperglycemia, hyponatremia, and hypokalemia, and urinalysis revealed proteinuria, glycosuria, and bilirubinuria. Examination of a bone marrow aspirate revealed profound hypoplasia of all precursors. Griseofulvin toxicosis was diagnosed on the basis of the temporal relationship of drug administration with onset of clinical, hematologic, and biochemical abnormalities and failure to identify an infective or neoplastic cause for the bone marrow hypoplasia. The condition was refractory to treatment and the cat was euthanatized. Pathologic changes in the bone marrow were consistent with severe hypoplasia of all bone marrow precursors.

Animals

Efficacy of chloramphenicol, enrofloxacin, and tetracycline for treatment of experimental Rocky Mountain spotted fever in dogs.

Dogs were experimentally inoculated with Rickettsia rickettsii to characterize the comparative efficacies of chloramphenicol, enrofloxacin, and tetracycline for the treatment of Rocky Mountain spotted fever (RMSF). All three antibiotics were equally effective in abrogating the clinical, hematologic, and vascular indicators of rickettsial infection. Antibiotic treatment for 24 h was sufficient to decrease the rickettsemia to levels below detection by Vero cell culture. Early treatment with all three antibiotics resulted in a similar decrease in antibody titer, but acute and convalescent serum samples taken at appropriate times would have still facilitated an accurate diagnosis of RMSF in all but one dog, which did not seroconvert. We conclude that chloramphenicol, enrofloxacin, and tetracycline are equally efficacious for treating experimental canine RMSF.

Animals

Postsurgical mortality secondary to zinc toxicity in dogs.

Zinc may be extremely toxic when absorbed from a metallic foreign body retained in the stomach. The most common cause of zinc toxicosis in dogs appears associated with accidental ingestion of copper-coated zinc pennies minted after 1982. In a retrospective literature search, zinc toxicosis due to penny ingestion was reported in 5 dogs, 2 of which died postoperatively, and 1 was euthanatized due to severe multiorgan system failure. In this report, we describe 3 additional cases of zinc toxicosis due to penny ingestion that resulted in a fatal outcome. Two dogs died during the early postoperative period, and another dog was euthanatized 5 d postoperatively due to continued deterioration. These cases emphasize the potential of perioperative complications associated with zinc toxicosis due to penny ingestion and suggest the need for better treatment options to decrease postsurgical mortality associated with this disease entity.

Animals

An epizootic of peroneal and tibial neuropathy in Walker Hound pups.

Early in life, Walker Hound pups from several litters, later determined to have peroneal and tibial neuropathy, had been given supplements of either evaporated milk and corn syrup mixed with well water or powdered bitch milk formula mixed with well water. Other pups not given supplements were not affected. Pelvic limb monoparesis, areflexia, analgesia, and muscular atrophy developed by 2 weeks of age. Abnormalities detected by light and electron microscopy included scattered swollen axons containing increased organelles and whorled neurofilaments. The clear association between clinical signs of disease and dietary supplementation of pups among healthy dogs in a kennel, as well as lack of an obvious pattern of inheritance, suggested an environmentally acquired toxin, specifically the well water. Attempts to reproduce neuropathy in a litter of Beagle pups 2 years after initial evaluation of the disease syndrome were unsuccessful. Atomic absorption studies performed on the well water to detect heavy metals did not reveal toxic concentrations. Toxins that may have been responsible for the neuropathy in these pups were not identified.

Animals

Vascular permeability and coagulation during Rickettsia rickettsii infection in dogs.

The vascular permeability of the ocular fundus, alterations in the coagulation system, and plasma concentrations of thromboxane B2 (TXB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) were studied in dogs following intradermal inoculation with 5 x 10(5) TCID50 of Rickettsia rickettsii. Twenty-four to 48 hours after the onset of fever and rickettsemia, multifocal areas of retinal vasculitis were evident, which corresponded to areas of altered vascular permeability demonstrated by fluorescein angiography. The number and intensity of retinal vessels with sodium fluorescein leakage peaked during the second week after inoculation, and retinal vascular permeability remained altered during the third week of infection, well past the phase of clinical and clinicopathologic recovery. Development of retinal vasculitic foci was associated with thrombocytopenia, increased concentrations of circulating fibrinogen, and slight prolongation of activated partial thromboplastin time. Increased concentrations of fibrin/fibrinogen degradation products were detected in 4 of 9 dogs. Despite the degree of vascular endothelial damage evident on fluorescein angiographic and histologic studies in these dogs, plasma TXB2 and 6-keto-PGF1 alpha concentrations were not increased.

6-Ketoprostaglandin F1 alpha