Kenneth R. Harkin

Isotype‐Specific Antibodies in Horses and Dogs with Immune‐Mediated Hemolytic Anemia

Classes of antibody bound to erythrocytes were determined using direct immunofluorescence (DIF) flow cytometry in 3 horses and 12 dogs with immune-mediated hemolytic anemia (IMHA). Background levels of antibody binding were determined in samples from 12 horses and 12 dogs that were free of clinical disease. The range of nonspecific binding of a fluorescein isothiocyanate (FITC)-conjugated goat anti-equine immunoglobulin G (IgG) was 19.9-36.7%, but was eliminated by the use of the F(ab)2 fragment of FITC-conjugated goat anti-equine IgG. Background binding by other class-specific antibodies to equine and canine erythrocytes was negligible. The DIF results were compared to the direct antiglobulin (Coombs) test in 5 horses and 20 dogs with anemia. The former assay was more sensitive in dogs with IMHA than was the Coombs test (100% versus 58%). In contrast, the Coombs test had better specificity than the DIF assay (100% versus 87.5%, respectively). Using clinical parameters or response to therapy as the comparison, the positive and negative predictive values for the DIF test were 92% and 100% compared to the values of the Coombs test of 100% and 62%. The DIF assay detected low levels of cells bound with antibody (<30%) in 5 dogs that were Coombs test-negative. For both species, performance of the DIF test was independent of the prozone effect. Five dogs with IMHA had IgG and IgM on erythrocytes, 5 had IgG, and 2 had IgM. Three horses had surface-bound IgG, including a horse with suspected penicillin-induced IMHA, a foal with neonatal isoerythrolysis, and a foal with clostridial septicemia. The DIF method was valuable in monitoring the response to therapy in the foal with neonatal isoerythrolysis.

Evaluations of land cover risk factors for canine leptospirosis: 94 cases (2002–2009)

Associations of land cover/land use variables and the presence of dogs in urban vs. rural address locations were evaluated retrospectively as potential risk factors for canine leptospirosis in Kansas and Nebraska using Geographic Information Systems (GIS). The sample included 94 dogs positive for leptospirosis predominantly based on a positive polymerase chain reaction test for leptospires in urine, isolation of leptospires on urine culture, a single reciprocal serum titer of 12,800 or greater, or a four-fold rise in reciprocal serum titers over a 2-4 weeks period; and 185 dogs negative for leptospirosis based on a negative polymerase chain reaction test and reciprocal serum titers less than 400. Land cover features from 2001 National Land Cover Dataset and 2001 Kansas Gap Analysis Program datasets around geocoded addresses of case/control locations were extracted using 2500m buffers, and the presence of dogs address locations within urban vs. rural areas were estimated in GIS. Multivariate logistic models were used to determine the risk of different land cover variables and address locations to dogs. Medium intensity urban areas (OR=1.805, 95% C.I.=1.396, 2.334), urban areas in general (OR=2.021, 95% C.I.=1.360, 3.003), and having urban address locations (OR=3.732, 95% C.I.=1.935, 7.196 entire study region), were significant risk factors for canine leptospirosis. Dogs regardless of age, sex and breed that live in urban areas are at higher risk of leptospirosis and vaccination should be considered.

Feline dysautonomia in the Midwestern United States: a retrospective study of nine cases

Dysautonomia of domestic animals is pathologically characterized by chromatolytic degeneration of the neurons in the autonomic nervous ganglia that results in clinical signs related to dysfunction or failure of the sympathetic and parasympathetic nervous systems. The exact cause is unknown. It has a poor prognosis among all species reported and no definitive treatment is available currently. To date, most reported feline cases have occurred in the United Kingdom and Scandinavia. The cases reported here highlight the clinical signs, physical examination findings, and results of autonomic nervous system function testing in nine cats with dysautonomia in the US. Feline dysautonomia is uncommon in the US, but may have a regional prevalence, as is seen in dogs with most cases reported in Missouri and Kansas.

Detection of Neospora caninum tachyzoites in cerebrospinal fluid of a dog following prednisone and cyclosporine therapy.

A 9-year-old female spayed Shetland Sheepdog was presented to the Kansas State University Veterinary Medical Teaching Hospital for evaluation following a 3-week history of left rear limb lameness that had progressed to generalized ataxia. Multifocal or diffuse brain lesions were suspected based on physical examination findings. Cerebrospinal fluid (CSF) contained 52 nucleated cells/μL composed of mixed inflammatory cells. Treatment with prednisone and cyclosporine was initiated based on a presumptive diagnosis of granulomatous meningoencephalitis. Thirteen days later the dog was nonambulatory and mentally obtunded. Repeat CSF analysis revealed 298 nucleated cells/μL with 61% eosinophils. Rare protozoal tachyzoites consistent with Neospora caninum, Toxoplasma gondii, or Sarcocystis spp. were found extracellularly and within macrophages and an eosinophil. Despite cessation of prednisone and cyclosporine therapy and provision of supportive care, the dog died 6 days later. Examination of brain tissue sections revealed multifocally extensive, necrotizing, histiocytic, and lymphoplasmacytic meningoencephalitis with numerous protozoal zoites and cysts. Immunohistochemical analysis of brain tissue using a monoclonal antibody specific for N. caninum confirmed the diagnosis of neosporosis. Similar but less severe lesions were noted in the spinal cord, although organisms were not found. This case emphasizes the value of repeated CSF analysis when therapy is ineffective and the importance of excluding infectious causes of meningoencephalitis before commencement of immunosuppressive therapy.

Feline histoplasmosis: fluconazole therapy and identification of potential sources of Histoplasma species exposure.

Feline histoplasmosis is a systemic fungal infection often treated with itraconazole, which can be cost-prohibitive for some clients. Additionally, although the clinical disease in cats has been documented, sources of Histoplasma species spore exposure in cats have yet to be thoroughly investigated. The objectives of this study were to compare the outcomes of cats with histoplasmosis treated with fluconazole to those treated with itraconazole, and to evaluate possible sources of exposure for affected cats. Medical records from feline patients with confirmed histoplasmosis (n = 32) at Kansas State University were systematically reviewed and follow-up was performed by owner telephone interview. Cats treated with fluconazole (n = 17) had similar mortality and recrudescence rates when compared with cats treated with itraconazole (n = 13). Thus, fluconazole may be a viable alternative therapy for the treatment of feline histoplasmosis. Eleven cats were housed strictly indoors and possible sources of exposure reported for these cats included potted plants (5/11) and unfinished basements (6/11).

Juvenile Pancreatic Atrophy in Greyhounds: 12 Cases (1995–2000)

BACKGROUNDnThis study describes compound failure of the endocrine and exocrine pancreas in Greyhounds, a condition that has not been reported in the veterinary literature.nnnOBJECTIVEnTo describe the clinical and pathologic findings in 12 Greyhounds with juvenile pancreatic atrophy.nnnANIMALSnTen Greyhounds presented for necropsy examination and 2 sibling Greyhounds presented for clinical evaluation before necropsy, all with a history of small-bowel diarrhea.nnnPROCEDURESnRetrospective study of laboratory and pathologic findings in 12 Greyhounds, including serum trypsin-like immunoreactivity assays, oral glucose tolerance testing, and serum anti-insulin antibody concentrations.nnnRESULTSnGross pancreatic atrophy was found in all 12 dogs. Histopathologic lesions were found in both the endocrine and exocrine pancreas and included acinar cell apoptosis, zymogen granule loss, cytoplasmic clearing or vacuolar change, lobular atrophy, islet loss, and lymphocytic or lymphoplasmacytic pancreatitis. Antemortem test results on the 2 Greyhound puppies indicated concurrent exocrine pancreatic insufficiency (EPI) and insulin-dependent diabetes mellitus (IDDM).nnnCONCLUSIONS AND CLINICAL IMPORTANCEnCompound failure of the exocrine and endocrine pancreas is rarely reported in dogs and neither disease is well recognized in the Greyhound. This condition is of potential economic importance to the Greyhound racing industry.

Evaluations of hydrologic risk factors for canine leptospirosis: 94 cases (2002-2009).

Hydrologic and soil-hydrologic variables were evaluated retrospectively as potential risk factors for canine leptospirosis in Kansas and Nebraska using Geographic Information Systems (GIS). The sample included 94 positive and 185 negative dogs for leptospirosis predominantly based on PCR test for leptospires in urine. Hydrologic variables for the region were derived from National Hydrographic Dataset, National Flood Hazard Layer, National Wetlands Inventory; and soil-hydrologic variables from Soil Survey Geographic Database around geocoded addresses of case/control locations. Multivariable logistic models were used to determine association between hydrologic and soil-hydrologic variables and test status. Distance from water features (OR=0.82; 95% CI=0.79, 0.86), hydrologic density (OR=2.80; 95% CI=1.58, 4.96) and frequently flooded areas (OR=4.05; 95% CI=2.17, 7.55) within 2500 m surrounding case/control locations were significant risk factors for canine leptospirosis. Vaccination for dogs that live closer to water features, landscapes dominated by water features and frequent floods should be considered for leptospirosis prevention.

Neighborhood-level socioeconomic and urban land use risk factors of canine leptospirosis: 94 cases (2002-2009).

Associations of housing, population, and agriculture census variables, and presence near public places were retrospectively evaluated as potential risk factors for canine leptospirosis using Geographic Information Systems (GIS). The sample population included 94 dogs positive for leptospirosis based on a positive polymerase chain reaction test for leptospires on urine, isolation of leptospires on urine culture, a single reciprocal serum titer of 12,800 or greater, or a four-fold rise in reciprocal serum titers over a 2-4 week period; and 185 dogs negative for leptospirosis based on a negative polymerase chain reaction test and reciprocal serum titers less than 400. Multivariable logistic regressions revealed different risk factors among different census units; however, houses lacking complete plumbing facilities [OR=2.80, 95% C.I.=1.82, 4.32 (census unit, block group); OR=1.36, 95% C.I.=1.28, 1.45 (census tract); OR=3.02, 95% C.I.=2.60, 3.52 (county)]; and poverty status by age (18-64) [OR=2.04, 95% C.I.=1.74, 2.39 (block group); OR=1.53, 95% C.I.=1.41, 1.67 (census tract); and OR=1.62, 95% C.I.=1.50, 1.76 (county)] were consistent risk factors for all census units. Living within 2500 m of a university/college and parks/forests were also significantly associated with leptospirosis status in dogs. Dogs that live under these circumstances are at higher risk for leptospirosis and pet owners should consider vaccination.

Erythrocyte-bound immunoglobulin isotypes in dogs with immune-mediated hemolytic anemia: 54 cases (2001–2010)

OBJECTIVEnTo identify erythrocyte-bound immunoglobulin (Ig) isotypes in dogs with primary immune-mediated hemolytic anemia (IMHA).nnnDESIGNnRetrospective case series. Animals-54 dogs with IMHA.nnnPROCEDURESnMedical records of dogs with IMHA diagnosed between January 2001 and April 2010 were examined. Immunoglobulin isotype (tested via direct immunofluorescence by flow cytometry to identify erythrocyte-bound Ig), Hct, serum bilirubin concentration, presence of autoagglutination, degree of spherocytosis, duration of hospitalization, and 90-day outcome were recorded.nnnRESULTSnThe Hct on admission was significantly lower in dogs with IgG and IgM isotypes bound to erythrocytes, compared with dogs with a single Ig isotype, and the degree of spherocytosis was greater in dogs with IgG and IgM bound to erythrocytes, compared with dogs that only had IgM. Dogs with only IgM were not more likely to have autoagglutination, compared with dogs that only had IgG on the erythrocyte surface. Although Ig isotype was not associated with survival time, initial serum total bilirubin concentration was higher in nonsurvivors.nnnCONCLUSIONS AND CLINICAL RELEVANCEnResults suggested that dogs with IMHA with ≥ 2 Ig isotypes bound to erythrocytes, particularly IgG and IgM, are likely to have a more severe degree of anemia, spherocytosis, and autoagglutination.

Iatrogenic, sulfonamide-induced hypothyroid crisis in a Labrador Retriever

This case report describes a sulfonamide-induced hypothyroid crisis in a 4-year-old Labrador Retriever bitch. Empirical therapy with high-dose trimethoprim-sulfamethoxazole for 10 days produced signs of weakness, ataxia and mental depression and the clinicopathological results supported hypothyroid-induced central nervous system depression. Short-term levothyroxine sodium therapy led to complete resolution of all clinical signs and follow-up thyroid hormone assays ruled out underlying thyroid pathology. This case report is the first to highlight this potentially life-threatening manifestation of sulfonamide-induced hypothyroidism. Sulfonamide combinations are widely used antimicrobials in veterinary medicine and early recognition of this syndrome is critical.