Progress 09/01/09 to 08/31/14
Outputs
Target Audience: Target audiences include the scientific community, specifically medical and veterinary entomologists who are concerned with fly movement from source areas to susceptible crops or animal populations, commodity groups, and food safety interest groups. Specifically: Scientific community: Livestock Workers Interest Group, S-1060, Entomological Society of America Commodity groups: Livestock associations, Leafy Greens growers, fruit and vegetable growers and packers Food Safety interest groups: Produce Marketing Association, Center for Food Safety, etc. These groups may be interested in the results obtained in the last year that shows flies specifically attracted to honeydew excretions Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? The project supported four graduate students and two post-docs. Each of these early professionals designed and carried out projects that resulted in theses, dissertations, and/or manuscripts. Specific training included learning pathogen transmission biology for flies, electron microscopy, PCR applications (real time, end point and relative quantitative), quantitative microbiology, and working with/maintaining filth fly colonies. All had and used opportunities to present their work at professional venues. As a result of these educational opportunities (learning to conduct research, publishing, giving professional talks), each of the students has successfully moved on to the next level (1 masters has moved on to a PhD program, 2 PhD students have a post doc and faculty position, respectively and the final PhD student will finish within 6 mo.). In addition to the graduate students, numerous undergraduates and summer workers had the opportunity to work on various aspects of the project, gaining valuable experience in both the labs and in the field. As a result, at least four have indicated a desire to enter graduate school and two are applying to vet school. These students have learned how to operate in a larger project and that thier contribution, no matter how small, adds to the overall success of the project. Just as important, the students learn that oversight or failure to complete something can result in significant delay or change an outcome. Finally, for the PIs, at the time of project initiation, two were Assistant Professors, and two were Associate Professors. This project enabled all four to successful move to Associate or Full Professor by providing opportunities to train students, conduct exciting and important research, present results at invited venues and learn how to succeed as a well-coordinated team. How have the results been disseminated to communities of interest? Dissemination has been primarily through four mechanisms: 1. Research venues, such as professional societies, has resulted in keeping the scientific community informed about our progress. We have presented talks and posters at the Entomological Society of America, the American Phytopathological Society, the International Food Protection Meetings, Livestock Insect Workers Conference, Center for Produce Safety, and Bioinformatics conferences (MCBios, IBM Almaden, Defense Threat Reduction Agency). 2. Invited seminars/presentations. Presentations have been made to University of Arkansas, Kansas State University, Texas A & M University, Oklahoma State University, University of Nebraska, & Escuela de las Fuerzos Armidas- ESPE, Quito, Ecuador, Catolic Pontifical University, Quito, Ecuador 3. Extension venues and meetings which include grower/rancher groups: Center for Produce Safety, Leafy Greens Growers Association, Master Ranchers Association, local extention meetings in Oklahoma, Texas, and California 4. Publication in scientific journals. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Four graduate students were trained; 3 of the 4 have graduated, 1 of the 4 expected to complete next year Two post-doctoral researchers were supported by this grant and they have gone on to professional careers One manuscript has been published, one has been submitted, and the remaining seven/eight manuscripts are ready to submit within 1-6 months Over 25 professional presentations have been made at regional, national, or international venues Scientific discoveries from reaching the research goals include the following: 1. Blow flies transmit significantly more E. coli O157:H7 cells to lettuce than do house flies 2. E. coli O157:H7 is transmitted at significantly higher rates of efficiency that is Salmonella enterica, by both blow flies and house flies 3. E. coli O157:H7 regurgitated onto spinach survives and replicates within depostited regurgitation spots 4. E. coli O157:H7 is retained on external fly body parts for up to 13 days post acquisition 5. Stable isotopes of flies reared on specific food materials are unique and reflect the rearing plant host sources. However, microbial communities are too unstable to be used as a reliable tool for fly origin determination 6. The microbial community of the blow fly excreta revealed numerous pathogens as well as benign organisms, but proved useful for fly-DNA free samples. 7. House flies are very attracted to homopteran honeydew. Volatiles associated with specific fungal infection (sooty mold) were found to attract flies under laboratory conditions 8. Assessment of fly dispersal distances was unsuccessful 9. Fly development and emergence from beef cadavers is severely reduced by composting
Publications
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2014
Citation:
Dubie, Trisha. 2014. Influence of Vegetative Height on Dispersal of House Flies from Livestock Facilities and Filth Fly Activity Associated with Composted and Non-composted Beef Cadavers, PhD. dissertation, Oklahoma State University
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2015
Citation:
Pace, R. J. Talley, & A. Wayadande. Phormia regina (Diptera: Calliphoridae) resting behavior on plants. Submitted to: J. Economic Entomol.
- Type:
Theses/Dissertations
Status:
Other
Year Published:
2015
Citation:
Hung, K. Attraction of House Flies to Volatiles Associated with Mealybug Honeydew (tentative). PhD. Dissertation, University of California, Riverside, Riverside, CA.
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2015
Citation:
Borrone, J. U. deSilva, J. Talley, P. Hoyt, and A. Wayadande. Metagenomic analysis of the blow fly (Diptera: Calliphoridae) excretome. To be submitted to J. Insect Science.
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2015
Citation:
R. Pace, J. Talley, T. Crippen & A. Wayadande. 2013. Vector competence for two foodborne pathogens, E. coli O157:H7 and Salmonella enterica, by two filth flies, Phormia regina (Diptera: Calliphoridae) and Musca domestica (Diptera: Muscidae). To be submitted to J. Med Vet.
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2015
Citation:
Hung, K., J. Millar, A. Wayadande, & A. Gerry. House fly attraction to insect honeydew. to be submitted to J. Med. Entomol.
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Progress 09/01/13 to 08/31/14
Outputs
Target Audience: Leafy Greens Growers Federal agencies in agriculture (USDA-ARS) Food Safety professionals in academia and industry Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Graduate student Rebecca Pace was successfully trained in livestock entomology and methods for handling vectors of human pathogens How have the results been disseminated to communities of interest? Yes, several presentations were made at professional venues and two papers were published. What do you plan to do during the next reporting period to accomplish the goals? This is the last year of the project
Impacts
What was accomplished under these goals?
This project focuses on insect transmission of human pathogens to plants. In 2013, a major research effort to understand fly transmission of two human pathogens, E. coli O157:H7 and Salmonella enterica to leafy greens by blow flies and house flies was completed. Three professional presentations were made and two manuscripts were published.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Wasala, L., J. Talley, U. Desilva, J. Fletcher and A. Wayadande. 2013. Transfer of Escherichia coli O157:H7 to spinach by house flies (Musca domestica). Phytopathology 103:373-380.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2013
Citation:
Pace, R. Interaction of Filth Flies, Plants, and Human Pathogens. Ph.D
dissertation, Oklahoma State University, Stillwater, OK
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Progress 09/01/12 to 08/31/13
Outputs
Target Audience: Leafy Greens Growers Federal agencies in agriculture (USDA-ARS) Food Safety professionals in academia and industry Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Graduate student Rebecca Pace was successfully trained in livestock entomology and methods for handling vectors of human pathogens How have the results been disseminated to communities of interest? Yes, several presentations were made at professional venues and two papers were published. What do you plan to do during the next reporting period to accomplish the goals? This is the last year of the project.
Impacts
What was accomplished under these goals?
This project focuses on insect transmission of human pathogens to plants. In 2013, a major research effort to understand fly transmission of two human pathogens, E. coli O157:H7 and Salmonella enterica to leafy greens by blow flies and house flies was completed. Three professional presentations were made and two manuscripts were published.
Publications
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2013
Citation:
Pace, R. Interaction of Filth Flies, Plants, and Human Pathogens. Ph.D
dissertation, Oklahoma State University, Stillwater, OK
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Wasala, L., J. Talley, U. Desilva, J. Fletcher and A. Wayadande. 2013. Transfer of Escherichia coli O157:H7 to spinach by house flies (Musca domestica). Phytopathology 103:373-380.
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Progress 09/01/11 to 08/31/12
Outputs
OUTPUTS: Vector competence experiments completed during 2012 indicate that blow flies and house flies are more efficient vectors of E. coli O157:H7 than Salmonella, though the mechanism of differential transmission is unclear. Variation in recovered GFP-tagged bacteria was high and may be indicative of highly variable acquisition of pathogen from inoculated manures. Metagenomic analysis of 454 massively parallel sequencing of blow fly excreta resulted in over 160,000 reads which were assigned to various taxa. There was very little contamination of fly genes, most of the assigned reads belonged to the Bacteriaceae, with a small component identified as fungi, eukaryotic DNA, and viruses. A SEED analysis within Megan4 identified numerous virulence related genes in the sample Bioassays conducted during 2011 and 2012 demonstrated that house flies do show an attractive response to a number of honeydew-contaminated crop plants relative to uncontaminated plant material from the same crop. Two different fungi were isolated and found to be at high concentration on honeydew-contaminated plant material that elicited an attractive response by house flies. These fungi were not present in high concentrations on plant material that did not elicit a house fly response during the bioassays. Fungi have been stored for colonization of sterile artificial honeydew to test whether volatiles identified as indicated below are the result of fungal presence on the honeydew. Preliminary analysis of honeydew volatiles by gas chromatography coupled with electroantennogram detection (GC-EAD) have indicated that there are several volatile compounds identified from attractive honeydew samples which bind to fly antennal receptors. We are in the process of confirming the identity of these volatile compounds and during 2013 will test house fly attraction response to each individual compound using our already developed bioassay methods. PARTICIPANTS: Co-PIs: Dr. Alec Gerry, UCR Dr. Udaya DeSilva, OSU Dr. Justin Talley, OSU Dr. Jacqueline Fletcher, OSU Dr. Li Ma, OSU Dr. Jocelyn Millar, UCR Dr. Themis Michaelides, UCD TARGET AUDIENCES: Leafy Greens Industry Livestock Industry Scientific community PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Wayadande, A. Bugs and Bacteria: Filth Fly Movement of Human Pathogens to Pre-Harvest Fresh Produce. Oct. 11, 2012. Invited Departmental Seminar, Kansas State University, Manhattan KS. Wayadande, A. Bugs and Bacteria: From Here to There September 4, 2012. Invited Departmental Seminar, Texas A & M. College Station, TX Pace, R., J. Talley, and A. Wayadande. Movement of E. coli O157:H7 and Salmonella enterica by the house fly, Musca domestica and the blow fly, Phormia regina, to lettuce. Invited symposium, NCB ESA, April 2012, Lincoln NE. Gerry, A. C. House fly response to honeydew volatiles. USDA Multi-state Project (S1030) Annual Meeting, San Antonio, TX. January 2012. Gerry, A. C. Research update on the house fly. Continuing Education Workshop, California Mosquito and Vector Control Association, Ontario, CA. January 2012. Hung, K. and A. C. Gerry. House fly (Musca domestica) responses to insect honeydew. Annual Meeting, Livestock Insect Workers Conference. Kalispell, MT. June 2012. Gerry, A. C. House fly resistance to pesticides. Annual Meeting, Society of Vector Ecology, Jacksonville, FL. September 2012. Hung, K. House fly (Musca domestica) response to insect honeydew. UCR Entomology Student Seminar Series. Riverside, CA. September 2012. Gerry, A. C. Nuisance fly management. Seminar Series, Target Specialty Products. Ontario, CA. October, 2012. Hung, K. and A. C. Gerry. House fly responses to insect honeydew. Annual Meeting, Entomological Society of America. Knoxville, TN. November 2012.
Publications
- No publications reported this period
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Progress 09/01/10 to 08/31/11
Outputs
OUTPUTS: Dissemination of information: Flies, Feet, and Food. Entomological Society of America, Indianapolis, IN. Presented 12/2009 Comparison of fly microbial diversity under controlled conditions. Facing Challenges of Vector Borne Disease in the 21st Century. Riverside, CA. Presented 1/2010. "Waiter there is a fly in my soup". 19th Annual Urban Pest Management Conference. University of California at Riverside. Riverside, CA. Presented on 03/2010. Filth fly reservoirs of E. coli O157:H7. California Leafy Greens Research Board. Huron, CA. Presented 3/2010. Protecting food crops from contamination with filth fly transmitted human pathogens. Annual Conference. American Society of Horticultural Scientists. Palm Desert, CA. Presented on 08/2010. Filth fly reservoirs of E. coli O157:H7. Central States Entomological Society. Presented 4/2010 Filth fly reservoirs of E. coli O157:H7. Center for Produce Safety Annual Symposium, Davis, CA. Presented 6/2010. Dissemination of Escherichia coli O157:H7 to spinach via regurgitation by house flies, Musca domestica L. International Association for Food Protection, Anaheim, CA. Presented 8/2010 Research update on arthropod pests of poultry. Quality Assurance Seminar. California Poultry Federation. Visalia, CA. Presented on 09/2010. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Objective 1: Fly origin: To determine if flies reared under different conditions have a unique cellular footprint, a stable isotope analysis was carried out on flies reared on 5 different substrates. The stable isotope analysis revealed discreet clustering of flies based upon C13/C14 and N15/N14 ratios. Objective 2: Fly-bacteria-plant interactions: A viable, working colony of calliphorid flies was established at Oklahoma State University. Using colony flies, a method of counting defecation and regurgitation spots on leaf surfaces was to estimate fly visitation was developed. A comparison of lettuce to marigold, sunflower, and wheat showed that blow flies alighted on lettuce and sunflower plants more often than on marigold plants. Regurgitation spots of house flies fed an attenuated strain of E. coli O157:H7 mixed with manure were found to contain bacteria that multiplied on the surface of spinach plants when detected by relative quantitative PCR. Bacteria were observed on the surface of plants in low numbers, but several cells had fimbria-like structures in contact with the plant surface. Similarly, E. coli O157:H7 was detected by serological and PCR methods on the cuticular surface of fly mouthparts and feet for up to 13 days after acquisition. These findings prompted the inclusion of an additional set of experiments designed to differentiate between live and dead bacteria associated with flies available for transmission to plants. Objective 3: Fly attraction to honeydew: Field flies have been colonized in the laboratory for use in bioassay methods development. Persistent sources of honeydew-producing insects have been located, including citrus scale, lerp psyllid, and whitefly. Apparatus for collecting honeydew and sooty mold volatiles has been developed, so that aging aliquots of honeydew from various sources can be repeatedly sampled over time to follow the change in the chemical profile of the odors as the honeydew is degraded by microorganisms and colonized by sooty molds. Laboratory trials demonstrated that recently colonized wild house flies are attracted to honeydew from citrus mealybugs reared on yellow squash. This honeydew was collected over several months and was colonized by a black sooty mold. House flies readily fed on this honeydew, increasing survival over water alone. Methods to isolate and identify fungi from honeydew samples have been developed, with collected honeydew dissolved in sterile water or washed from leaf material using Tween 20 and sterile water. The honeydew solutions were further diluted in sterile water or Tween 20 and sterile water. Aliquots of the diluted honeydew were plated on acidified PDA plates, incubated at 25 C, and resulting colonies were identified to species and enumerated. Identified yeasts and fungi have been stored for future colonization of sterile artificial honeydew. Objective 4: Outreach to leafy greens growers and livestock facility managers: Contacts have been made with area dairies and cow-calf operators via professional cattlemen associations in California and Oklahoma and onsite visits are planned for 2011.
Publications
- Wasala, L. 2010. Dissemination of Escherichia coli O157:H7 to the spinach, Spinacea oleraceae, phylloplane by house flies, Musca domestica L. Masters thesis, Oklahoma State University, Stillwater, OK 74078
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Progress 09/01/09 to 08/31/10
Outputs
OUTPUTS: none to date. PARTICIPANTS: Dr. Alec Gerry, UCR Dr. Udaya DeSilva, OSU Dr. Justin Talley, OSU Dr. Jacqueline Fletcher, OSU Dr. Li Ma, OSU Dr. Jocelyn Millar, UCR Dr. Themis Michaelides, UCD TARGET AUDIENCES: Leafy Greens Industry Livestock Industry Scientific community PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Food safety has become a major concern for the leafy greens industry and US consumers of fresh produce. Recent foodborne pathogen outbreaks in spinach, lettuce, and other unprocessed vegetables has led to an examination of the epidemiology of several foodborne pathogens, including E. coli O157:H7 and Salmonella enterica. These pathogens are often associated with animal/poultry operations and pathways for movement of these bacteria to plants include contaminated water, soil, fertilizer, and compost. One little studied pathway of contamination is that of filth flies which are known to harbor these pathogens and others. This project seeks to understand how filth flies are involved in contamination of leafy greens. We will to use forensic strategies to determine the origin of flies that are found in leafy greens and other pre-harvest vegetables. This may be necessary in the event of another enteric bacterial outbreak where traceback to a point source(s) is desirable. Second, we do not know filth fly transmission efficiency of enteric bacteria to plants, the persistence of enteric bacteria associated with flies, nor do we know what distances to known fly sources are safe to recommend to avoid/prevent bacterial contamination. Because cattle and poultry are known to harbor many human pathogens and sometimes are identified as sources for outbreaks, it is important to assess the true risk that flies (which develop in these animal production areas) pose to vegetable and fruit growers. It is equally important to protect animal producers from unwarranted condemnation when disease outbreaks occur. We will test dispersal distances of feral flies with the ultimate goal of recommending buffer zones between cattle feedlot-rangeland areas that will afford protection to both producers and feedlot operators. Finally, understanding why flies move to plants is the first step in avoiding pre-harvest contamination. Documentation of fly attraction to homopteran honeydew will provide additional incentive for growers to avoid aphid/whitefly infestations and enable growers to recognize situations in which food safety may be an issue in their cropping systems.
Publications
- No publications reported this period
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