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<OL> <LI> Demonstrate starling-to-calf and calf-to-starling transmission of E. coli O157. The working hypothesis of this aim is that foodborne pathogens are excreted in starling droppings in sufficient numbers and in a metabolic state capable of causing bovine colonization. This aim will also serve to determine the duration and magnitude of E. coli O157 excretion by starlings. <LI> Determine frequency of bovine exposure to E. coli O157-contaminated starling excrement. The working hypothesis of this aim is that birds isolated from the dairy farm environment have a high prevalence of E. coli O157 and that livestock feed contamination by birds is frequent on dairy farms with bird problems. <LI> Determine the role starlings in the spatial dissemination of E. coli O157 to dairy farms. The working hypotheses of this aim are that individual European starlings visit multiple farms during daily feeding behavior and that indistinguishable subtypes of E. coli O157 can be isolated from starlings on multiple dairy farms within their home flight range. <LI> Determine the relative contribution large of on-farm starling populations to the prevalence of bovine E.coli O157 colonization on dairy farms.</ol>
The working hypothesis of this aim is that farms with starling problems will be more likely to have cattle positive for E. coli O157 than farms where starlings are infrequently present. The extent of any differences will be important in assessing the overall potential impact of starling control activities.
NON-TECHNICAL SUMMARY: European starlings, Sturnus vulgaris, congregate by the thousands and feed at cattle operations. These birds are considered nuisance pests because of the large amount of livestock feed they consume and the contamination of the farm environment with excrement that they produce. Although Escherichia coli O157:H7, Salmonella spp., and Campylobacter jejuni have been isolated from these birds, the extent that these birds contribute to the dissemination of pathogens of importance to food safety and animal health has not been determined. The purpose of this project is to determine extent that these birds contribute to the epidemiology of foodborne pathogens in cattle.
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APPROACH: Controlled laboratory-based experiments are coupled with GIS-assisted mapping and molecular epidemiological feild studies to analyze E.coli O157 isolates and movement patterns of wild European starlings. The extend of distribution of birds and indistinguishable subtypes of E. coli O157 on diary farms will be determined.
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PROGRESS: 2007/08 TO 2008/07<br>
OUTPUTS: Activities: On-farm activities included the collection of bovine fecal samples on dairy farms and the collection of excrement from European starlings. Radiotelemetry to track the movement of starling among dairy farms continued. Laboratory experiments were used to assess the duration and magnitude of E. coli O157 shedding from starlings. The survival of E. coli O157 in starling guano was determined. Events: Results of these experiments were presented at local and National (vertebrate pest conference, Managing Blackbirds, Starlings and Crows conference). Services The PI was involved in the workshop discussion and priority setting of the USDA Wildlife Service's Managing Blackbirds, Starlings and Crows Conference, Nashville. Products and Dissemination information concerning the health risk posed by wildlife, particularly European starlings, was disseminated to lay press. A summary of discoveries was published in the Vertebrate Pest Conference (23rd) Proceedings <br> <br>
IMPACT: 2007/08 TO 2008/07<br>
Change in knowledge: European starlings visit multiple farms in a single day. Given the ease at which E. coli O157 is transmitted between cows and birds, and vis-versa, these birds are capable of transmitting foodborne bacteria from farm-to-farm. Stricter control of these birds on dairy farms is warranted. Change in actions: Although changes in action are needed, additional appropriate guidelines and methods to successfully exclude birds from dairy farms is desperately needed. Producers (dairy and vegetable producers are trying to more accurately quantify the damage caused by these birds. Change in conditions: None to date. <br> <br>
PROGRESS: 2006/08/01 TO 2007/07/31<br>
Introduction: The sources of novel strains of Escherichia coli O157 on closed dairy herds and on vegetable production sites are unknown. Wild birds,particularly European Starlings (Sturnus vulgaris), are known to frequent farms and can carry E. coli O157 and other foodborne bacterial pathogens. Purpose: The objective of this study was to determine 1) the minimum infectious dose required for E. coli O157 to colonize starlings; 2) the duration of E. coli O157 shedding by starlings; and 3) the magnitude of E. coli O157 shedding by starlings. Methods: Wild-caught European starlings were individually housed and orally inoculated with various doses of E. coli O157. E. coli O157 present in the excrement of individual birds was determined by quantitative culture methods. Results: Birds that were given 104 or less CFU (n = 30) shed the organisms for less than three days, whereas birds dosed with 105 or more CFUs (n = 20) excreted the organisms for 10 days. The average magnitude of E. coli O157 among positive birds, 3 log CFU/g, did not differ with inoculum dose. The concentration of E. coli O157 in bird guano stored at room temperature decreased by 2-log units over a 2-week period. E. coli O157 was transferred between starlings and calves following cohabitation for one day.
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IMPACT: 2006/08/01 TO 2007/07/31<br>
Significance: European starlings can readily acquire E. coli O157 from bovine sources and subsequently serve as a vector for dissemination of this pathogen to cattle farms, and possibly also to fields were crops are grown.