Texas A&M University
1.
Graham, Sherry Lynn.
Prevalence and spatial distribution of antibodies to Salmonella enterica serovar Typhimurium O antigens in bulk milk from Texas dairy herds.
Degree: MS, Veterinary Medicine and Surgery, 2004, Texas A&M University
URL: http://hdl.handle.net/1969.1/450 
The purpose of this study was to describe the herd antibody status to Salmonella Typhimurium as estimated from co-mingled milk samples and to describe the resulting geographical patterns found in Texas dairy herds. Bulk tank milk samples were collected from 852 Grade A dairies throughout Texas during the summer of 2001. An indirect enzyme-linked immunosorbent assay (ELISA) using S. Typhimurium lipopolysaccharide was performed with signal to noise ratios calculated for each sample. The ELISA ratio was used in fitting a theoretical variogram and kriging was used to develop a predicted surface for these ratios in Texas. A spatial process with areas of higher risk located in the panhandle and near Waller County was apparent. Lower risk areas included Atascosa, Cooke, Collin, Titus, Comanche and Cherokee Counties. Subsets representing large dairy sheds in northeast Texas, the Erath County area, and the Hopkins County area were also evaluated individually. Each result illustrated a spatial process with areas of low and high ELISA ratio predictions. Cluster analysis was performed for the entire state with cases defined as herds having milk ELISA ratios greater than or equal to 1.8. Using this cutoff, the prevalence of herds with positive bulk tank milk ELISAs was 4.3%. Significant clustering of cases was demonstrated by the Cuzick and Edward's test. The spatial scan statistic then identified the two most likely clusters located in and near the Texas Panhandle. This study demonstrated that the distribution of S. Typhimurium antibodies in bulk tank milk in Texas is describable by a spatial process. Knowledge of this process will help elucidate geospatial influences on the presence of S. Typhimurium in dairy herds and enhance our understanding of the epidemiology of salmonellosis.
Advisors/Committee Members: Thompson, James A. (advisor), Barling, Kerry S. (advisor), Scott, H. Morgan (committee member), Waghela, Suryakant (committee member).Subjects/Keywords: salmonella; spatial; dairy; milk
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APA (6th Edition):
Graham, S. L. (2004). Prevalence and spatial distribution of antibodies to Salmonella enterica serovar Typhimurium O antigens in bulk milk from Texas dairy herds. (Masters Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/450
Chicago Manual of Style (16th Edition):
Graham, Sherry Lynn. “Prevalence and spatial distribution of antibodies to Salmonella enterica serovar Typhimurium O antigens in bulk milk from Texas dairy herds.” 2004. Masters Thesis, Texas A&M University. Accessed January 19, 2021.
http://hdl.handle.net/1969.1/450.
MLA Handbook (7th Edition):
Graham, Sherry Lynn. “Prevalence and spatial distribution of antibodies to Salmonella enterica serovar Typhimurium O antigens in bulk milk from Texas dairy herds.” 2004. Web. 19 Jan 2021.
Vancouver:
Graham SL. Prevalence and spatial distribution of antibodies to Salmonella enterica serovar Typhimurium O antigens in bulk milk from Texas dairy herds. [Internet] [Masters thesis]. Texas A&M University; 2004. [cited 2021 Jan 19].
Available from: http://hdl.handle.net/1969.1/450.
Council of Science Editors:
Graham SL. Prevalence and spatial distribution of antibodies to Salmonella enterica serovar Typhimurium O antigens in bulk milk from Texas dairy herds. [Masters Thesis]. Texas A&M University; 2004. Available from: http://hdl.handle.net/1969.1/450
Texas A&M University
2.
Bissett, Wesley Thurlow, Jr.
Ecosystem health at the texas coastal bend: a spatial analysis of exposure and response.
Degree: PhD, Veterinary Microbiology, 2009, Texas A&M University
URL: http://hdl.handle.net/1969.1/ETD-TAMU-2126
This dissertation investigated locational risks to ecosystem health associated with
proximity to industrial complexes. The study was performed at the behest of ranchers
and citizens living and working down-prevailing wind from the Formosa Plastics, Inc.
and ALCOA facilities located in Calhoun County, Texas. Concerns expressed were for
potential genotoxicity resulting from exposure to complex chemical mixtures released by
the facilities. Exposure assessment of the marine environment was performed with
sediments and oysters from Lavaca Bay being analyzed. Numerous chemicals were
found to be present at concentrations considered likely to result in adverse responses in
exposed populations. Bayesian geostatistical analysis was performed to determine if the
concentrations were affected by a spatial process. Mercury and polycyclic aromatic
hydrocarbons were the most notable of the chemicals found to be present at elevated
concentrations and affected by a spatial process. Evaluation of maps generated from
spatial modeling revealed that proximity to ALCOA resulted in elevated risks for
exposure to harmful concentrations of pollutants. Genotoxicity was measured in two
sentinel species. Oysters (Crassostrea virginica) were utilized for evaluation of the
marine environment and cattle (Bos taurus and Bos taurus crossbred cattle) were chosen
for evaluation of the terrestrial environment. Chromosomal aberration analysis was
performed on oyster hematocytes. Analysis of the results failed to demonstrate the
presence of an important generalized spatial process but some specific locations close to
the ALCOA plant had elevations in this measure of genotoxicity. Stress as measured by
the lysosomal destabilization assay was also performed on oyster hematocytes. These results were found to be affected by a significant spatial process with the highest degree
of destabilization occurring in close proximity to ALCOA. Genotoxicity in cattle was
evaluated with the single cell gel electrophoresis assay and chromosomal aberration
analysis. Bayesian geostatistical analyis revealed the presence of important spatial
processes. DNA-protein cross-linkage was the most notable with a strong indication of
increased damage down-prevailing wind from the industrial complexes. Results
indicated that proximity to industrial facilities increased the risk for harmful exposures,
genotoxicity, and lysosomal destabilization.
Advisors/Committee Members: Adams, L. Garry (advisor), Thompson, James A. (advisor), Field, Robert (committee member), Moyer, William (committee member), Phillips, Timothy (committee member), Scott, H. Morgan (committee member).Subjects/Keywords: genotoxicity; sentinnel species; biomarkers; spatial analysis; Bayesian analysis
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APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Bissett, Wesley Thurlow, J. (2009). Ecosystem health at the texas coastal bend: a spatial analysis of exposure and response. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/ETD-TAMU-2126
Chicago Manual of Style (16th Edition):
Bissett, Wesley Thurlow, Jr. “Ecosystem health at the texas coastal bend: a spatial analysis of exposure and response.” 2009. Doctoral Dissertation, Texas A&M University. Accessed January 19, 2021.
http://hdl.handle.net/1969.1/ETD-TAMU-2126.
MLA Handbook (7th Edition):
Bissett, Wesley Thurlow, Jr. “Ecosystem health at the texas coastal bend: a spatial analysis of exposure and response.” 2009. Web. 19 Jan 2021.
Vancouver:
Bissett, Wesley Thurlow J. Ecosystem health at the texas coastal bend: a spatial analysis of exposure and response. [Internet] [Doctoral dissertation]. Texas A&M University; 2009. [cited 2021 Jan 19].
Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2126.
Council of Science Editors:
Bissett, Wesley Thurlow J. Ecosystem health at the texas coastal bend: a spatial analysis of exposure and response. [Doctoral Dissertation]. Texas A&M University; 2009. Available from: http://hdl.handle.net/1969.1/ETD-TAMU-2126
Open Access Theses and Dissertations