Comparison of results for serologic testing and a polymerase chain reaction assay to determine the prevalence of stray dogs in eastern Tennessee seropositive to Ehrlichia canis

OBJECTIVE: To determine the prevalence of stray dogs in eastern Tennessee seropositive to Ehrlichia canis and examine the correlation between results for an ELISA, indirect immunofluorescent antibody (IFA) test, and polymerase chain reaction (PCR) assay. SAMPLE POPULATION: Blood samples obtained from 90 adult dogs admitted to an animal shelter in eastern Tennessee. PROCEDURE: Serum samples were analyzed for antibodies against E. canis by use of a commercially available ELISA kit, 2 IFA tests, and a PCR assay; testing was performed at the University of Tennessee (TN) and North Carolina State University (NCSU). The PCR amplification was performed by use of DNA extracted from EDTA-anticoagulated blood and primers designed to amplify DNA of Ehrlichia spp. RESULTS: Antibodies against E. canis were detected in only 1 dog by use of the ELISA. By IFA testing at TN, 10 of 90 (11%) dogs were seroreactive against E. canis antigens, all of which had medium to high titers to E. canis. Only 5 of the 10 TN seroreactors were also reactive against E. canis antigens in IFA tests conducted at NCSU, and all 5 had low to medium titers. The DNA of Ehrlichia spp was not amplified in any blood samples by use of PCR assays conducted at the TN or NCSU. CONCLUSIONS AND CLINICAL RELEVANCE: The discordant ELISA, IFA, and PCR results obtained in this study were unexpected and may have been related to exposure of dogs to an Ehrlichia species other than E. canis, such as E. ewingii.     

Pig weaning weight and changes in hematology and blood chemistry of sows injected with recombinant porcine somatotropin during lactation

Weaning weight of pigs on d 18 to 21 of age was used to determine the effects of recombinant porcine somatotropin (rpST) on lactational performance of their dams. Crossbred Landrace x Yorkshire sows (n = 180, 202 to 270 kg BW) were assigned to receive daily i.m. injections of either 0, 8, or 16 mg of rpST on lactation d 7 to 20. Initially, injections of 16 mg of rpST/d caused 100% mortality (four sows); thus, a dose of 4 mg of rpST/d replaced 16 mg. Subsequently, 5 of 19 and 1 of 17 sows died in response to daily injections of 8 and 4 mg of rpST, respectively, resulting in termination of the experiment. Before termination, 48 sows (16 from each of the 0-, 4-, and 8-mg treatment groups) completed a lactation of 18 to 21 d in duration. Analysis of these data indicated that daily injection of lactating sows with rpST increased (P less than .05) weaning weight of pigs only if they were from litters that averaged greater than or equal to 2.6 kg/pig on lactation d 7. The BW of sows was decreased by rpST (P = .07). Subsequent experiments revealed 1) that rpST-induced death of lactating sows was caused from hemorrhaging of ulcers that developed at the pars esophagea, 2) that there was vacuolation of the liver and kidney of dead sows, and 3) that daily injection of 16 mg of rpST into nonlactating growing pigs (50 to 100 kg BW) for 28 d did not cause death or any observable illness in spite of 100% mortality of lactating sows after two to nine injections.     

Tibial fractures

Tibial fractures are common in small animal practice. As with other appendicular fractures, the patient's age, fracture location, and fracture type must be considered thoroughly. While methods for tibial fracture repair are similar to those used for appendicular fractures elsewhere, there are some unique considerations, both anatomically and functionally, that must be contemplated before repair. The following article will review the incidence of tibial fractures, tibial fracture types, and options for tibial fracture management and treatment. The use of external fixators, orthopedic bone plates, open reduction with internal fixation (ORIF), and external coaptation will be discussed. An emphasis will be placed on the most common types of tibial fractures, as well as those best suited for repair by general practitioners of veterinary medicine. Three case based examples will follow the overview.     

A screening test for subclinical liver disease in horses affected by pyrrolizidine alkaloid toxicosis

Objective: To evaluate various biochemical tests as indicators of subclinical liver disease in horses exposed to pyrrolizidine alkaloid toxicosis.
Design: A clinical pathology field study.
Animals: Twenty-two clinically normal horses from four properties in the Kimberley region of Western Australia.
Procedure: Serum samples from each horse were assayed for gamma glutamyltransferase, alkaline phosphatase and aspartate aminotransferase activities, and for serum bile acid concentration, albumin and total protein. Serum protein electrophoresis was performed and their amino acid profiles determined. Bromosulphophihalein halfclearance times were measured. Horses were then subjected to a single liver biopsy. Results were analysed by, variance of group means, the Fisher-Irwin exact test, and by sensitivity and specificity calculation.
Results: Horses were classified into 2 groups, of 10 unaffected and 12 subclinically affected, on the basis of liver histology. Significant differences between the unaffected and subclinical groups were observed for gamma glutamyltransferase and alkaline phosphatase activities (P < 0.01). Gamma glutamyltransferase had sufficient sensitivity (75%) and specificity (90%) to function as a primary screening test for subclinical liver disease in horses exposed to pyrrolizidine alkaloids. Alkaline phosphatase was useful, but with lower sensitivity (58%).
Conclusion: Serum gamma glutamyltransferase activity is a useful screening test for detecting subclinical liver disease in horses exposed to pyrrolizidine alkaloids under field conditions in northern Australia.     

Reduced growth of Lucilia cuprina larvae fed serum from sheep treated with anthelmintics

The effect of three commonly used anthelmintics, levamisole hydrochloride, ivermectin and closantel, on the development of the sheep blowfly, Lucilia cuprina, was determined. Sheep were treated with each anthelmintic using the manufacturers' recommended dose for helminth control. Both ivermectin and closantel significantly (p < 0.05) reduced the growth rate of larvae of L cuprina cultured in vitro on serum from these sheep. Levamisole hydrochloride had no effect. Ivermectin was effective for less than 6 days after treatment, whereas closantel significantly reduced larval growth 21 days after treatment. Dose-response experiments showed that lower concentrations of both ivermectin and closantel were not as effective in reducing larval growth.     

Contaminant Mobility in Soils Amended with Fly Ash and Flue-Gas Gypsum: Intact Soil Cores and Repacked Columns

The impact of the land application of coal combustion by-products, fly ash (FA) and flue-gas desulfurization gypsum(FDG), to coarse-textured soils of the southeastern U.S.A. wasinvestigated using batch and dynamic column techniques. Two FAsamples, one an alkaline FA (Alk-FA) and the other an acidic FA(Acid-FA), were evaluated alone and in combination with FDG assoil amendments to an Appling loamy sand (Typic Hapludults). Theeffects of these waste products on clay dispersion, soilhydraulic conductivity (K_sat) and the migration ofcontaminants such as Arsenic (As) and Boron (B) were studiedusing intact soil cores and repacked soil columns. FA or combinationsof FA + FDG were applied to the surface of intact soil cores (10 Mg ha^-1) and repacked soil columns or incorporated withinrepacked soil columns. The columns were saturated and thenleached for a prescribed number of pore volumes to simulateleaching conditions in the field. Effluent pH, electricalconductivity (EC), and turbidity were monitored and leachatefractions were collected for B, As, Ca, Mg, K and Na analysis.Both FA materials were ineffective at decreasing the inherentdispersibility of clay from the A_p horizon in batch tests.In fact, high application rates of the Alk-FA induced some claydispersion in the well-flocculated B_t soil materials, andcolumn results suggest that incorporating the Alk-FA within thesurface soil may actually reduce K_sat. In contrast,treatments with FDG were highly effective at inducing rapid clayflocculation in batch tests and eliminating effluent turbidityfor intact and repacked soil columns. Boron was readily mobilefrom both intact and repacked soil columns, a majority of whichleached from the columns within the first three pore volumes.Boron leaching was greater for combined treatments (FA + FDG),possibly indicative of enhanced solubilization in the presenceof FDG or sulfate (SO₄ ^2-) competition for sorptionsites. Arsenic levels present in the leachates from FA and FDGcolumns were generally lower than control columns and roughlycorrelated with effluent turbidity. Combined treatments (FA +FDG) enhanced Mg and K leaching due to the added competition ofCa for cation exchange sites. Following leaching, the intactsoil cores were sectioned at 5 cm intervals and the pH and EC ofthe soil, as well as the vertical distribution of As and B, weredetermined. Levels of residual As were only slightly higher in the upper section of the FA-amended columns, showing little downward movement, but no clear trend in residual B was observed due to its greater mobility.