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Salmonella and E coli O157:H7 in Livestock at Agricultural Fairs Thomas E. Wittum, PhD Veterinary Preventive Medicine The Ohio State University
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Salmonella spp Multiple host species Multiple host species Fecal-oral transmission Fecal-oral transmission Important zoonotic food-borne pathogen Important zoonotic food-borne pathogen Can persist in the environment Can persist in the environment Frequently shed by healthy animals Frequently shed by healthy animals Ubiquitous in the environment Ubiquitous in the environment
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Human illness caused by Salmonella Incubation 6-72 hours Incubation 6-72 hours Diarrhea/bloody diarrhea Diarrhea/bloody diarrhea Abdominal cramps Abdominal cramps Fever Fever Self-limiting except for immunosuppressed Self-limiting except for immunosuppressed
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Escherichia coli O157:H7 Multiple host species Multiple host species Fecal-oral transmission Fecal-oral transmission Important zoonotic food-borne pathogen Important zoonotic food-borne pathogen Can persist in the environment Can persist in the environment Frequently shed by healthy animals Frequently shed by healthy animals Seasonality of shedding Seasonality of shedding
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Human illness caused by O157:H7 Incubation 1-10 days Incubation 1-10 days Abdominal cramps and diarrhea Abdominal cramps and diarrhea Bloody diarrhea Bloody diarrhea Hemolytic uremic syndrome (HUS) Hemolytic uremic syndrome (HUS) Antimicrobial therapy is contraindicated Antimicrobial therapy is contraindicated
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Zoonotic transmission Primarily food-borne Primarily food-borne Direct animal to human transmission can and does occur easily in environments conducive to interaction Direct animal to human transmission can and does occur easily in environments conducive to interaction Not an efficient mode of transmission Not an efficient mode of transmission Some environments provide the opportunity for high-level exposure of high-risk individuals Some environments provide the opportunity for high-level exposure of high-risk individuals Animal exhibits Animal exhibits Agricultural fairs Agricultural fairs
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Outbreaks at Animal Exibits Salmonella Salmonella 1991 Seattle Pacific Science Center 1991 Seattle Pacific Science Center 1996 Denver Zoological Gardens 1996 Denver Zoological Gardens E coli O157:H7 E coli O157:H7 2000 Washington petting zoo 2000 Washington petting zoo 2000 Pennsylvania petting zoo 2000 Pennsylvania petting zoo
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The ~3500 US State Fairs (large, regional) & County Fairs (small, local) attract ~150 million visitors annually Fairs provide opportunity for direct & sometimes intimate human contact with livestock, including children Several European & N American human STEC O157 outbreaks linked w/ visits to farms & fairs exhibiting livestock US Agricultural Fairs
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Risk for outbreaks at fairs Most fairs held in summer or early fall Most fairs held in summer or early fall warm weather warm weather Mix urban/suburban children with farm livestock Mix urban/suburban children with farm livestock Multiple US county fair outbreaks since 1998 Multiple US county fair outbreaks since 1998 Most US fair outbreaks linked to: contaminated water supplies direct contact w/ ruminants (cattle, sheep, goats) airborne transmission (dust?) from livestock barns
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E coli O157:H7 fair outbreaks 1999 1999 New York, Washington Co Fair 610 (171)Water New York, Washington Co Fair 610 (171)Water Ontario, Canada Fair 159 (7)Petting zoo Ontario, Canada Fair 159 (7)Petting zoo 2000 2000 Ohio, Medina Co Fair 39Water Ohio, Medina Co Fair 39Water 2001 2001 Wisconsin, Ozaukee Co Fair 56Animal contact Wisconsin, Ozaukee Co Fair 56Animal contact Ohio, Lorain Co Fair 40Show barn Ohio, Lorain Co Fair 40Show barn Ohio, Wyandot Co Fair 20Hand washing Ohio, Wyandot Co Fair 20Hand washing
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E coli O157:H7 fair outbreaks 2002 2002 Oregon, Lane Co Fair 86Sheep/goat barn Oregon, Lane Co Fair 86Sheep/goat barn 2003 2003 Texas, Fort Bend Co Fair7Animal contact Texas, Fort Bend Co Fair7Animal contact 2004 2004 North Carolina State Fair112Petting zoo North Carolina State Fair112Petting zoo 2005 2005 Florida, multiple fairs/festivals72Petting zoo Florida, multiple fairs/festivals72Petting zoo
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Agricultural Fair Livestock Husbandry & management very different than commercial livestock Husbandry & management very different than commercial livestock Anti-thesis of factory farming Anti-thesis of factory farming Meticulously groomed, cleaned & bathed before/during fairs Meticulously groomed, cleaned & bathed before/during fairs Typically extremely well-cared for and well-fed Typically extremely well-cared for and well-fed Exhibitors work to impress judges with the good condition of their livestock and hygiene of their pens (competitions) Exhibitors work to impress judges with the good condition of their livestock and hygiene of their pens (competitions) Usually reared individually or in small groups Usually reared individually or in small groups Market weight animals typically sold at end of fair Market weight animals typically sold at end of fair Often very tame & friendly towards people Often very tame & friendly towards people
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Fairs represent particularly intense episodes of close contact between large numbers of humans, farm animals, and food/beverage vendors in the presence of unregulated water systems Jay Varma, CDC, Sept 2002
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Objective To estimate fecal Salmonella and E coli O157:H7 prevalence in livestock on display at US agricultural fairs
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Sampling County fairs (n=29) County fairs (n=29) 22 fairs visited in State A (July-Oct 2002) 22 fairs visited in State A (July-Oct 2002) 7 fairs visited in State B (July-Aug 2002) 7 fairs visited in State B (July-Aug 2002) 25 cattle, 25 pigs, other species & flies as available 25 cattle, 25 pigs, other species & flies as available State Fairs (n=3) State Fairs (n=3) 3 State Fairs: A, B, and C; visited Aug, Sept, & Oct, 2002 3 State Fairs: A, B, and C; visited Aug, Sept, & Oct, 2002 60-70 market & breeding beef, swine, & dairy cattle 60-70 market & breeding beef, swine, & dairy cattle Other species (sheep, goats, flies) as available Other species (sheep, goats, flies) as available
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Sampling Bacterial culture Bacterial culture Availability sampling of individuals Availability sampling of individuals Fair, owner, & animal anonymity required Fair, owner, & animal anonymity required All samples cultured for Salmonella spp and E coli O157:H7 All samples cultured for Salmonella spp and E coli O157:H7 Other non-O157 STEC Other non-O157 STEC
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Samples Collected 2919 freshly ground-deposited livestock feces 2919 freshly ground-deposited livestock feces one sample per animal or pen (pigs, sheep, goats) one sample per animal or pen (pigs, sheep, goats) 154 fly pools 154 fly pools ~8,000 blow flies, stable flies, & house flies ~8,000 blow flies, stable flies, & house flies live trapped or netted from dumpsters, garbage cans, wash stations, livestock buildings, etc live trapped or netted from dumpsters, garbage cans, wash stations, livestock buildings, etc
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Salmonella fecal prevalence in fair livestock Beef cattle 4.7% Dairy cattle 4.7% Sheep 5.2% Goats 4.9% Swine 39.3% Other livestock 4.6%
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E coli O157 fecal prevalence in fair livestock Beef cattle 13.8% Dairy cattle 5.9% Sheep 5.2% Goats 2.8% Swine 3.6% Other livestock 0%
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Results Salmonella spp Isolated from livestock at most fairs (96% fair prevalence) 16.4% prevalence in fly pools E coli O157:H7 Isolated from livestock at all 29 county fairs & all 3 State Fairs (100% fair prevalence) 7.1% prevalence in fly pools 1 human STEC O157 hemorrhagic colitis case linked with visit to one of the sampled county fairs
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Demonstration Milk Cows One cow was shedding E coli O157:H7 Second cow had Salmonella hide contamination Contact with hundred of children per day
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Hand Sanitizing Stations 17 located in animal barns at State Fair A 17 located in animal barns at State Fair A First check 5/17 usable First check 5/17 usable Second check 6/17 usable Second check 6/17 usable No stations observed at State Fair B No stations observed at State Fair B
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Follow-up testing Fair environmental samples collected prior to summer 2003 fair Fair environmental samples collected prior to summer 2003 fair Both Salmonella spp and E coli recovered from fair environments Both Salmonella spp and E coli recovered from fair environments Environmental persistence of isolates Environmental persistence of isolates
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Conclusions Salmonella spp common at US fairs, esp in swine fecal prevalence similar to summer prevalence in commercial livestock present in swine & ruminants frequent in/on pest flies (vector?)
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common at US fairs, esp in cattle fecal prevalence similar to summer prevalence in commercial livestock present in swine & ruminants frequent in/on pest flies (vector?) Conclusions E coli O157:H7
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Recommendations ?? CDC Provide information about risk Provide information about risk Design venue to minimize risk Design venue to minimize risk Adequate hand-washing facilities Adequate hand-washing facilities Prohibit hand-to-mouth activities in animal interaction areas Prohibit hand-to-mouth activities in animal interaction areas Heightened precautions for high-risk individuals Heightened precautions for high-risk individuals
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Additional Possibilities?? Test animals prior to fair entry Test animals prior to fair entry Limitations of tests Limitations of tests Disinfection of fair environment Disinfection of fair environment Nearly impossible to disinfect agricultural environment Nearly impossible to disinfect agricultural environment Treatment of animals prior to fair entry Treatment of animals prior to fair entry Oral neomycin Oral neomycin
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