Clinical and hematologic effects of experimental infection of dogs with recently identified Babesia gibsoni-like isolates from Oklahoma

OBJECTIVE: To characterize clinical and hematologic responses in dogs following experimental inoculation with Babesia gibsoni-like isolates from infected dogs in Oklahoma. DESIGN: Prospective study. 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.     

Comparison of core needle biopsy and fine-needle aspiration of enlarged peripheral lymph nodes for antemortem diagnosis of enzootic bovine lymphosarcoma in cattle

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. DESIGN: Prospective study. 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 fine-needle 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.     

Sample collection and preparation in cytology: increasing diagnostic yield.

Cytology is a valuable diagnostic tool for examining many types of lesions. The diagnostic yield of cytology is dependent on optimal sample collection and smear preparation. This article outlines the basic techniques for collection of samples via fine-needle biopsy, imprints, scrapings, and swabs. Tips are given on how to avoid some of the most common problems that lead to nondiagnostic samples.     

Disseminated protothecosis diagnosed by evaluation of CSF in a dog

A 5-year-old female spayed Shetland Sheepdog Mix dog was evaluated for a history of recent seizure activity, progressive hind limb ataxia, polyuria, and polydipsia and no history of gastrointestinal signs. Physical examination findings included conscious proprioceptive deficits, ataxia, and anterior uveitis along with a hypermature cataract in the right eye. Results of a CBC, serum biochemical profile, urinalysis, and computed tomography scan of the brain were unremarkable. Cerebrospinal fluid (CSF) analysis revealed marked eosinophilic pleocytosis and rare organisms consistent with Prototheca spp within neutrophils and macrophages. On postmortem histologic examination, mononuclear inflammation and numerous intralesional algal organisms, similar to those seen on the cytologic preparation of CSF, were found in the brain, eyes, kidneys, and heart. Abnormalities were not detected on gross and histologic examination of the gastrointestinal tract. Cultures of CSF and subdural/olfactory bulb, but not intestinal tract, yielded growth of Prototheca spp, and PCR analysis and DNA sequencing confirmed the organism as Prototheca zopfii genotype 2. We have reported a rare case of disseminated protothecosis that was diagnosed by evaluation of CSF in a dog presented with neurologic signs and no overt enteric disease. Protothecosis should be considered as a rare cause of seizures, even in the absence of obvious enteric signs, and should be included in the differential diagnosis of eosinophilic pleocytosis.     

Cytologic identification of immature endospores in a dog with rhinosporidiosis

An 8-year-old, intact, male Labrador Retriever was presented to the Boren Veterinary Medical Teaching Hospital at Oklahoma State University with a 2-month history of severe sneezing episodes that resulted in epistaxis and bilateral sanguineous discharge. Rhinoscopy revealed a small polypoid mass, and specimens were obtained for histopathology. Microscopic examination of formalin-fixed tissue specimens revealed organisms consistent with Rhinosporidium seeberi. The mass was surgically excised and impression smears were made for cytology examination. Smears revealed high numbers of endospores, typical of those previously described for R seeberi. In addition, numerous smaller structures, presumed to be immature endospores, were noted. The immature endospores were morphologically distinct from mature endospores and have not been described previously. Recognition of immature forms of Rhinosporidium may help prevent misidentification of the organism or misdiagnosis of a dual infection.