Doctor of Philosophy

dissertationToo often, prescription medications once thought safe for human use cause unacceptable adverse health consequences and fail during clinical testing or are recalled after public release. One major contributing factor to this problem is the inability of cu

Escherichia coli, Salmonella, and Mycobacterium avium subsp. paratuberculosis in Wild European Starlings at a Kansas Cattle Feedlot

The prevalence of Escherichia coli, Salmonella spp., and Mycobacterium avium subsp.paratuberculosis isolated from the feces of wild European starlings (Sturnus vulgaris) humanely trapped at a feedlot in central Kansas was assessed. All E. coli and Salmonellaisolates recovered were tested for antimicrobial susceptibility using National Antimicrobial Resistance Monitoring System panels and the E. coli isolates were classified as to their content of genes associated with pathogenic E. coli of birds and cattle, including cvaC, iroN2, ompTp, hlyF2, eitC, iss, iutA, ireA, papC, stxI, stxII, sta, K99, F41, and eae.Escherichia coli O157:H7 and Mycobacterium avium subsp. paratuberculosis were not detected and Salmonella was isolated from only three samples, two of which displayed antimicrobial resistance. Approximately half of the E. coli isolates were resistant to antimicrobial agents with 96% showing resistance to tetracycline. Only one isolate was positive for a single gene associated with bovine pathogenic E. coli. An interesting finding of this study was that 5% of the E. coli isolates tested met the criteria established for identification as avian pathogenic E. coli (APEC). Thus these findings suggest that starlings are not a significant source of Salmonella spp., Mycobacterium avium subsp.paratuberculosis, E. coli O157, or other shiga toxin–producing E. coli in this feedlot. However, they may have the potential to spread APEC, an important pathogen of poultry and a potential pathogen to human beings

Using radio-telemetry to assess the risk European starlings pose in pathogen transmission among feedlots

We monitored site-use and movements of 102 radio-tagged European starlings (Sturnus vulgaris) during the winter months at 2 concentrated animal feeding operations (feedlots) in central Kansas. Our research investigated the spatial ecology of wintering starlings as part of a broad epidemiological study on the possible role of starlings in pathogen transmission at feedlots. Site fidelity was 0.677 and 0.552 (days at capture-site per total days tagged) for feedlots A and B, respectively. Minimal exchange (9%) occurred between feedlots A and B and was often followed by a roost-site change. Starlings rarely abandoned the feedlot where they were captured, but we observed 41 (40%) birds that temporarily switched allegiance from their capture sites to other feedlots; the farthest bird was detected 68 km from the capture site. We speculate that the limited frequency of time spent at non-capture-site feedlots could lower the potential for risk of starlings spreading pathogens among feedlots. We suggest management strategies within the feedlot that may reduce starling populations and speculate that this would lower the risk of spreading pathogens among feedlots

Band Encounters of Wintering European Starlings Captured in Kansas, Nebraska, and Texas

European starlings (Sturnus vulgaris) are agricultural and societal pests in the U.S., thus, understanding their migratory behavior is of practical importance to resource managers. We leg-banded starlings and used publicly reported encounters with them to estimate migration distances traveled by wintering populations to reach their reproductive territories. We captured and banded 9,939 starlings at 6 sites between November and February 2005–2010 in 3 states. We banded birds in industrial areas surrounding Omaha, Nebraska, and at cattle feedlots in central Kansas (n = 2) and the Texas Panhandle (n = 3). Banding sites were associated with wintering aggregations that caused agricultural or urban conflicts. Thirty band encounters (0.3%) occurred between April–August, which we defined as the reproductive period. The median number of days between date of banding and date of encounter was 170 (n = 28, Range: 66–862; Q3–Q1 = 361). We categorized encounters as either regional (≥80 km) or local (\u3c80 \u3ekm). Median distance of regional encounters was 421 km (n = 16, Range: 125–1,384; Q3–Q1 = 456); median distance of local encounters was 24 km (n = 14, Range: 12–75, Q3–Q1 = 5). The regional encounters occurred on a median bearing from the banding sites +12° from true north (n = 16, Range: -18–67; Q3–Q1 = 26). Starlings are renowned and persistent pests, and the birds from our study areas probably contributed to agricultural and urban conflicts in several states

Pathogenic Diseases and Movements of Wintering European Starlings Using Feedlots in Central Kansas

Kansas is a major producer of livestock and has an abundance of over-wintering European starlings. Roost sizes for over-wintering starlings can be as large as 5 million individuals. Starlings cause a substantial amount of economic damage to farmers. Escherichia coli O157:H7 and Salmonella can cause illness in both livestock and humans, and cattle with Johne’s disease must be culled. Crohn’s disease in humans is suspected to be caused from Mycobacterium avium subsp. paratuberculosis (Johne’s disease). We banded, leg-flagged, and radio-tagged starlings using feedlots near Great Bend, Kansas. Our objectives were to track daily movements of starlings visiting feedlots in this area and screen starlings for E. coli O157:H7, Salmonella spp., and M. a. subsp. paratuberculosis. Preliminary data show that starlings in Kansas are moving among feedlots rather than remaining at one feedlot. Pathogens were detected at a low prevalence. Our results can be used to develop plans for the management of transmissible diseases carried by starlings

\u3ci\u3eEscherichia coli, Salmonella\u3c/i\u3e, and \u3ci\u3eMycobacterium avium\u3c/i\u3e subsp. \u3ci\u3eparatuberculosis\u3c/i\u3e in Wild European Starlings at a Kansas Cattle Feedlot

The prevalence of Escherichia coli, Salmonella spp., and Mycobacterium avium subsp. paratuberculosis isolated from the feces of wild European starlings (Sturnus vulgaris) humanely trapped at a feedlot in central Kansas was assessed. All E. coli and Salmonella isolates recovered were tested for antimicrobial susceptibility using National Antimicrobial Resistance Monitoring System panels and the E. coli isolates were classified as to their content of genes associated with pathogenic E. coli of birds and cattle, including cvaC, iroN2, ompTp, hlyF2, eitC, iss, iutA, ireA, papC, stxI, stxII, sta, K99, F41, and eae. Escherichia coli O157:H7 and Mycobacterium avium subsp. paratuberculosis were not detected and Salmonella was isolated from only three samples, two of which displayed antimicrobial resistance. Approximately half of the E. coli isolates were resistant to antimicrobial agents with 96% showing resistance to tetracycline. Only one isolate was positive for a single gene associated with bovine pathogenic E. coli. An interesting finding of this study was that 5% of the E. coli isolates tested met the criteria established for identification as avian pathogenic E. coli (APEC). Thus these findings suggest that starlings are not a significant source of Salmonella spp., Mycobacterium avium subsp. paratuberculosis, E. coli O157, or other shiga toxin–producing E. coli in this feedlot. However, they may have the potential to spread APEC, an important pathogen of poultry and a potential pathogen to human beings

Escherichia coli, Salmonella, and Mycobacterium avium subsp. paratuberculosis in Wild European Starlings at a Kansas Cattle Feedlot

The prevalence of Escherichia coli, Salmonella spp., and Mycobacterium avium subsp.paratuberculosis isolated from the feces of wild European starlings (Sturnus vulgaris) humanely trapped at a feedlot in central Kansas was assessed. All E. coli and Salmonellaisolates recovered were tested for antimicrobial susceptibility using National Antimicrobial Resistance Monitoring System panels and the E. coli isolates were classified as to their content of genes associated with pathogenic E. coli of birds and cattle, including cvaC, iroN2, ompTp, hlyF2, eitC, iss, iutA, ireA, papC, stxI, stxII, sta, K99, F41, and eae.Escherichia coli O157:H7 and Mycobacterium avium subsp. paratuberculosis were not detected and Salmonella was isolated from only three samples, two of which displayed antimicrobial resistance. Approximately half of the E. coli isolates were resistant to antimicrobial agents with 96% showing resistance to tetracycline. Only one isolate was positive for a single gene associated with bovine pathogenic E. coli. An interesting finding of this study was that 5% of the E. coli isolates tested met the criteria established for identification as avian pathogenic E. coli (APEC). Thus these findings suggest that starlings are not a significant source of Salmonella spp., Mycobacterium avium subsp.paratuberculosis, E. coli O157, or other shiga toxin–producing E. coli in this feedlot. However, they may have the potential to spread APEC, an important pathogen of poultry and a potential pathogen to human beings.This article is from Avian Diseases 53, no. 4 (2009): 544–551, doi:10.1637/8920-050809-Reg.1.</p

Sexual selection constrains the body mass of male but not female mice

Abstract Sexual size dimorphism results when female and male body size is influenced differently by natural and sexual selection. Typically, in polygynous species larger male body size is thought to be favored in competition for mates and constraints on maximal body size are due to countervailing natural selection on either sex; however, it has been postulated that sexual selection itself may result in stabilizing selection at an optimal mass. Here we test this hypothesis by retrospectively assessing the influence of body mass, one metric of body size, on the fitness of 113 wild‐derived house mice (Mus musculus) residing within ten replicate semi‐natural enclosures from previous studies conducted by our laboratory. Enclosures possess similar levels of sexual selection, but relaxed natural selection, relative to natural systems. Heavier females produced more offspring, while males of intermediate mass had the highest fitness. Female results suggest that some aspect of natural selection, absent from enclosures, acts to decrease their body mass, while the upper and lower boundaries of male mass are constrained by sexual selection

Data from: Sexual selection constrains the body mass of male but not female mice

Sexual size dimorphism results when female and male body size is influenced differently by natural and sexual selection. Typically, in polygynous species larger male body size is thought to be favored in competition for mates and constraints on maximal body size are due to countervailing natural selection on either sex; however, it has been postulated that sexual selection itself may result in stabilizing selection at an optimal mass. Here we test this hypothesis by retrospectively assessing the influence of body mass, one metric of body size, on the fitness of 113 wild-derived house mice (Mus musculus) residing within ten replicate semi-natural enclosures from previous studies conducted by our laboratory. Enclosures possess similar levels of sexual selection, but relaxed natural selection, relative to natural systems. Heavier females produced more offspring, while males of intermediate mass had the highest fitness. Female results suggest that some aspect of natural selection, absent from enclosures, acts to decrease their body mass, while the upper and lower boundaries of male mass are constrained by sexual selection