Wesley T. Bissett

Use of Walpole's solution for treatment of goats with urolithiasis: 25 cases (2001–2006)

OBJECTIVE To determine results of ultrasound-guided cystocentesis and percutaneous infusion of Walpoles solution for treatment of male goats with urolithiasis. DESIGN Retrospective case series. ANIMALS 25 male goats with urolithiasis treated with Walpoles solution. PROCEDURES Information obtained from the medical records included signalment, degree of urethral obstruction (partial vs complete), pertinent examination findings, concurrent illnesses, diet, other treatments administered, duration of hospitalization, whether the obstruction resolved, and outcome (ie, discharged vs euthanized). RESULTS 14 (58%) animals had complete urethral obstruction, and 10 (42%) had partial obstruction (degree of urethral patency was not recorded in 1 animal). Walpoles solution was infused once in 18 (72%) animals, twice in 6 (24%) animals, and 3 times in 1 (4%) animal. The amount of Walpoles solution required to achieve the target urine pH of 4 to 5 ranged from 50 to 250 mL. In 20 (80%) goats, the urethral obstruction resolved, and the goat was discharged. The remaining 5 (20%) goats were euthanized because of unresolved urethral obstruction. Six of the 20 (30%) goats that were discharged were reexamined because of recurrence of urethral obstruction. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that ultrasound-guided cystocentesis in combination with percutaneous infusion of Walpoles solution may be a useful treatment in male goats with obstructive urolithiasis.

Comparison of three treatment regimens for sheep and goats with caseous lymphadenitis.

OBJECTIVE To compare the effectiveness of 3 treatment regimens for small ruminants with caseous lymphadenitis. DESIGN Randomized clinical trial. ANIMALS 44 client-owned sheep and goats. PROCEDURES Aspirates were obtained from 48 lesions of 44 enrolled animals and submitted for bacterial culture. Animals were randomly assigned to 1 of 3 treatment groups. Treatment for group A (n = 15 lesions) consisted of opening, draining, and flushing the lesions and SC administration of procaine penicillin G. Treatment for group B (n = 15 lesions) consisted of closed-system lavage and intralesional administration of tulathromycin. Treatment for group C (n = 18 lesions) consisted of closed-system lavage and SC administration of tulathromycin. All animals were reexamined approximately 1 month after treatment, unless treatment failure was detected prior to that time. RESULTS 43 animals with lesions had positive results (Corynebacterium pseudotuberculosis) for bacterial culture. Proportions of lesions that had resolution of infection by 1 month after treatment did not differ significantly among the treatment groups (group A, 13/14 [92.9%]; 95% confidence interval [CI], 69.5% to 99.6%; group B, 10/12 [83.3%]; 95% CI, 54.9% to 97.1%; and group C, 14/17 [82.4%]; 95% CI, 59.1% to 95.3%). CONCLUSIONS AND CLINICAL RELEVANCE Acceptable alternatives to opening, draining, and flushing of lesions may exist for treatment of sheep and goats with caseous lymphadenitis. Use of tulathromycin and penicillin in this study constituted extralabel drug use, which would require extended withholding times before milk or meat of treated sheep and goats can be sold for human consumption.

Serologic and bacteriologic culture prevalence of Corynebacterium pseudotuberculosis infection in goats and sheep and use of Bayesian analysis to determine value of assay results for prediction of future infection

OBJECTIVE To determine the serologic and bacteriologic culture prevalence of Corynebacterium pseudotuberculosis infection in sheep and goats and the value of such assays for prediction of future development of caseous lymphadenitis (CL). DESIGN Observational study. ANIMALS 919 goats and sheep in 3 herds in southwest Texas. PROCEDURES During an initial evaluation, serologic and bacteriologic culture status for CL was determined for all animals. Subsequently, animals were evaluated every 6 months for a 13-month period to detect external CL lesions. Affected animals in 2 herds were treated with tulathromycin or a control treatment; affected animals in 1 herd were culled. The value of assays for prediction of future development of CL lesions was determined. RESULTS The serologic prevalence of CL in herds at the start of the study ranged from 7.52% to 69.54%. The bacteriologic culture prevalence of CL ranged from 0% to 6.12% at the start of the study and 0% to 9.56% at the end of the study. Synergistic hemolysin inhibition results were poor predictors of future development of CL lesions in animals during the study period; however, animals with positive bacteriologic culture results for CL were more likely to develop lesions in the future than were animals with negative bacteriologic culture results. CONCLUSIONS AND CLINICAL RELEVANCE Caseous lymphadenitis was detected in animals in this study despite prior management of affected animals in herds via culling. Use of a synergistic hemolysin inhibition test for management of CL may cause unnecessary culling of animals; treatment might allow retention of genetically valuable CL-affected animals in a herd without substantially increasing the prevalence of CL.

Risks of childhood cancer among Texas watersheds, based on mothers' living locations at the time of birth

The risk characterization method employed by US EPA to quantitatively characterize the benefits of the Groundwater Rule (GWR) for drinking water computes person-to-person transmission intensity as the product of the number of primary illnesses and a static secondary morbidity factor. A population level infectious disease health effects model is used here to evaluate the implications of secondary transmission on exposures to viruses that are relevant to the GWR. These implications are evaluated via a hypothetical case study in which it is assumed that a tour group from a large population centre visits an outlying area that is served by a non-community water system with untreated or inadequately treated groundwater that is contaminated with a highly infectious virus. It is assumed that some of the exposed individuals become infected and then return home. Numerical simulations are used to estimate the subsequent number of additional infections and illnesses due to secondary transmission within the large community. The results indicate that secondary transmission could substantially impact the predicted benefits of the GWR depending on the suite of population dynamic elements and assumptions employed.Cancer is the most common fatal disease among US children. The fetus has reduced resistance to toxic injury and is especially prone to mutagenic injury because of the high rate of cell division. A fetus can be exposed to environmental toxins through maternal consumption of contaminated water. The objective of this study was to estimate the incidence risk for childhood cancers within each watershed in Texas. The approach modeled risk for 19 cancer histotypes incorporating correlations among the cancer types and spatial correlation. Several watersheds in a very large area known as the Central Great Plains of North Texas were associated with increased risk for astrocytoma. Two watersheds near Houston, Buffalo-San Jacinto and West Galveston Bay, had increased risk for renal cancer and acute lymphoid leukemia, respectively. A watershed in South Texas, the South Laguna Madre, had increased risk for atypical leukemias. The possibility that waterborne toxins cause these childhood cancers should be investigated further.

Sperm DNA quality evaluated by comet assay and sperm chromatin structure assay in stallions after unilateral orchiectomy

Unilateral orchiectomy (UO) may interfere with thermoregulation of the remaining testis caused by inflammation surrounding the incision site, thus altering normal spermatogenesis and consequently sperm quality. Two measures of sperm DNA quality (neutral comet assay and the sperm chromatin structure assay [SCSA]) were compared before UO (0 days) and at 14, 30, and 60 days after UO to determine whether sperm DNA changed after a mild testis stress (i.e., UO). The percent DNA in the comet tail was higher at 14 and 60 days compared to 0 days (P < 0.05) after UO. All other comet tail measures (i.e., length, moment, migration) were higher at all time periods after UO compared to 0 days (P < 0.05). Two SCSA measures (mean-αt, mode-αt) increased at 14 days after UO (P < 0.05), whereas two measures (SD-αt and COMP-αt) did not change. This study identified a decrease in sperm DNA quality using both the neutral comet assay and the SCSA, which was not identified using traditional measures of sperm quality.

Risk factors associated with nasopharyngeal cicatrix syndrome in horses

OBJECTIVE To determine risk factors associated with the development of nasopharyngeal cicatrix syndrome (NCS) in horses. DESIGN Retrospective case-control study. ANIMALS 242 horses referred for endoscopic evaluation of the upper portion of the respiratory tract (121 horses with NCS and 121 control horses). PROCEDURES Medical records of horses that had an endoscopic evaluation of the upper airway performed between January 2003 and December 2008 were reviewed. Signalment, housing management, and season of evaluation were recorded and reviewed for each horse. The associations between clinical signs and endoscopic findings were evaluated by the use of a prospective logistic model that included a Bayesian method for inference. Results-Breed and sex had no significant effect on the risk of having NCS. The risk that a horse had NCS increased significantly with age. Exclusive housing in a stall was protective against the development of NCS. In addition, the amount of pasture turnout had a dose-related effect, with exclusive pasture turnout positively correlated with increased risk of developing NCS, compared with a mixture of pasture turnout and stall confinement. Horses were significantly more likely to be evaluated because of clinical signs of the syndrome during the warm months of the year. CONCLUSIONS AND CLINICAL RELEVANCE The risk factors for NCS identified in this study may support chronic environmental exposure to an irritant or infectious agent as the cause of NCS. Information gained from this study should be useful for investigating the cause of NCS.

Bayesian spatial modeling of Lavaca Bay pollutants

Locational risk of increased mercury and PAH concentrations in Lavaca Bay, Texas sediments and eastern oysters (Crassostrea virginica) harvested from Lavaca Bay, Texas were analysed. Chemical analysis results were evaluated utilizing Bayesian geo-statistical methods for comparison of the model fit of a random effects model versus a convoluted model which included both random and spatial effects. For those results fit best with the convoluted model, continuous surface maps of predicted parameter values were created. Sediment and oyster concentrations of mercury and the majority of measured PAHs were fit best with the convoluted model. The locational risks of encountering elevated concentrations of these pollutants in Lavaca Bay sediments and oysters were highest in close proximity to industrial facilities.

Management of a pet dog after exposure to a human patient with Ebola virus disease.

In October 2014, a health-care worker who had been part of the treatment team for the first laboratory-confirmed case of Ebola virus disease imported to the United States developed symptoms of Ebola virus disease. A presumptive positive reverse transcription PCR assay result for Ebola virus RNA in a blood sample from the worker was confirmed by the CDC, making this the first documented occurrence of domestic transmission of Ebola virus in the United States. The Texas Department of State Health Services commissioner issued a control order requiring disinfection and decontamination of the health-care workers residence. This process was delayed until the patients pet dog (which, having been exposed to a human with Ebola virus disease, potentially posed a public health risk) was removed from the residence. This report describes the movement, quarantine, care, testing, and release of the pet dog, highlighting the interdisciplinary, one-health approach and extensive collaboration and communication across local, county, state, and federal agencies involved in the response.

Caprine Abscess Model of Tulathromycin Concentrations in Interstitial Fluid from Tissue Chambers Inoculated with Corynebacterium pseudotuberculosis following Subcutaneous or Intrachamber Administration

ABSTRACT Corynebacterium pseudotuberculosis causes chronic, suppurative, abscessing conditions in livestock and humans. We used an in vivo model to evaluate antimicrobial efficacy for focal abscesses caused by C. pseudotuberculosis. Tissue chambers were surgically implanted in the subcutaneous tissues of the right and left paralumbar fossa of 12 goats to serve as a model for isolated, focal abscesses. For each goat, one tissue chamber was inoculated with C. pseudotuberculosis, while the contralateral chamber served as an uninoculated control. Six goats were administered a single dose of tulathromycin at 2.5 mg/kg of body weight subcutaneously, while the other six received the same dose by injection directly into the inoculated chambers. Our objective was to compare the effects and tulathromycin concentrations in interstitial fluid (IF) samples collected from C. pseudotuberculosis-infected and control chambers following subcutaneous or intrachamber injection of tulathromycin. In addition, the effects of tulathromycin on the quantity of C. pseudotuberculosis reisolated from inoculated chambers were assessed over time. Tulathromycin IF concentrations from C. pseudotuberculosis-infected and control tissue chambers were similar to those in plasma following subcutaneous administration. Following intrachamber administration, tulathromycin IF concentrations in infected chambers were continuously above the MIC for the C. pseudotuberculosis isolate for 15 days. There were no significant differences for plasma area under the curve and elimination half-lives between subcutaneous and intrachamber administration. Six of the 12 infected chambers had no growth of C. pseudotuberculosis 15 days postadministration. Results of this study indicate that tulathromycin may be beneficial in the treatment of focal infections such as those caused by C. pseudotuberculosis.

Geostatistical analysis of biomarkers of genotoxicity in cattle, Bos taurus and Bos taurus × Bos indicus, sentinels near industrial facilities

This study, performed at the behest of ranchers living and working down-prevailing wind from industrial facilities located in Calhoun County, Texas investigated locational risks to ecosystem health associated with proximity to specific industrial complexes. Concerns expressed were for potential genotoxicity in cattle resulting from the release of complex chemical mixtures. The Comet Assay and flow cytometric evaluation of variations in DNA content were utilized to evaluate DNA damage. Bayesian geo-statistical analysis revealed the presence of important spatial processes. The Comet assay’s optical density provided a strong indication of increased damage down-prevailing wind from the industrial complexes. Results indicated that proximity to and location down-prevailing winds from industrial facilities increased the locational risk of genotoxicity in this sentinel species.