Lee Wisener - Academia.edu (original) (raw)

Papers by Lee Wisener

Animal Health Research Reviews

Livestock producers are encouraged to reduce the use of antibiotics belonging to classes of medic... more Livestock producers are encouraged to reduce the use of antibiotics belonging to classes of medical importance to humans. We conducted a scoping review on non-antibiotic interventions in the form of products or management practices that could potentially reduce the need for antibiotics in beef and veal animals living under intensive production conditions. Our objectives were to systematically describe the research on this broad topic, identify specific topics that could feasibly support systematic reviews, and identify knowledge gaps. Multiple databases were searched. Two reviewers independently screened and charted the data. From the 13,598 articles screened, 722 relevant articles were charted. The number of relevant articles increased steadily from 1990. The Western European research was dominated by veal production studies whereas the North American research was dominated by beef production studies. The interventions and outcomes measured were diverse. The four most frequent inte...

Animal health research reviews, Jan 11, 2017

Acupuncture has become increasingly popular in veterinary medicine. Within the scientific literat... more Acupuncture has become increasingly popular in veterinary medicine. Within the scientific literature there is debate regarding its efficacy. Due to the complex nature of acupuncture, a scoping review was undertaken to identify and categorize the evidence related to acupuncture in companion animals (dogs, cats, and horses). Our search identified 843 relevant citations. Narrative reviews represented the largest proportion of studies (43%). We identified 179 experimental studies and 175 case reports/case series that examined the efficacy of acupuncture. Dogs were the most common subjects in the experimental trials. The most common indication for use was musculoskeletal conditions, and the most commonly evaluated outcome categories among experimental trials were pain and cardiovascular parameters. The limited number of controlled trials and the breadth of indications for use, outcome categories, and types of acupuncture evaluated present challenges for future systematic reviews or meta-...

Zoonoses and Public Health, 2014

Human illness due to infections with Escherichia coli O157 is a serious health concern. Infection... more Human illness due to infections with Escherichia coli O157 is a serious health concern. Infection occurs through direct contact with infected animals or their faeces, through contaminated food or water and/or through person-to-person transmission. A reduction in faecal E. coli O157 shedding in cattle might reduce the burden of human infections. We used systematic review and meta-analysis to assess the efficacy of direct-fed microbials (DFM), compared with placebo or no treatment, fed during the pre-harvest stage of production in reducing faecal E. coli O157 shedding in beef cattle during field trials. Four electronic databases, Nebraska Beef Reports and review article reference lists were searched. A total of 16 publications assessing faecal shedding at the end of the trial and/or throughout the trial period were included. The majority of publicly disseminated trials evaluated the prevalence of E. coli O157 faecal shedding; only two evaluated the concentration of organisms in faeces. The prevalence of faecal E. coli O157 shedding in cattle is significantly reduced by DFM treatments (summary effect size for all DFM - OR = 0.46; CI = 0.36-0.60). The DFM combination Lactobacillus acidophilus (NP51) and Propionibacterium freudenreichii (NP24) was more efficacious in reducing the prevalence of faecal E. coli O157 shedding at the time of harvest and throughout the trial period compared with the group of other DFM, although this difference was not statistically significant. Furthermore, we found that the combination [NP51 and NP24] treatment was more efficacious in reducing the prevalence of faecal E. coli O157 shedding at the time of harvest and throughout the trial period when fed at the dose of 10(9) CFU/animal/day than any lesser amount, although this difference was not statistically significant. Feeding beef cattle DFM during the pre-harvest stage of production reduces the prevalence of E. coli O157 faecal shedding and might effectively reduce human infections.

Zoonoses and Public Health, 2013

Reducing zoonotic pathogens in food animals prior to harvest will reduce the pathogen burden that... more Reducing zoonotic pathogens in food animals prior to harvest will reduce the pathogen burden that enters the food chain and the environment. Consequently, the burden of enteric illness in humans may be reduced. Evaluating interventions to reduce a pathogen in animals often begins with challenge trials, in which animals are deliberately exposed to the pathogen under controlled conditions. Challenge trials are subsequently followed by field trials, also known as randomized controlled trials, in which the animals are naturally exposed to the pathogen. Challenge trials can most effectively inform field trials only if they precede field trials, are robust, internally valid and transparently reported. Using systematic review and meta-analysis methodology, we examined the pre-harvest food safety literature for three intervention-pathogen-species combinations: probiotics/competitive exclusion products in ruminants to reduce Escherichia coli O157 shedding, vaccines in ruminants to reduce E. coli O157 shedding and vaccines in swine to reduce Salmonella shedding. We examined two outcomes, prevalence of faecal shedding at the end of the trial and prevalence of faecal shedding throughout the trial period, to compare challenge trials and field trials. We found that challenge trials occurred concurrently with field trials, challenge trials suffered from reporting deficiencies of methodological features, challenge trials tended to report a more favourable outcome than field trials, and there was some evidence of publication bias among all three intervention-pathogen-species combinations. Challenge trials would better serve to inform field trials if they precede field trials, are methodologically sound, include transparent reporting and are published regardless of their results. In addition, due to our findings of greater efficacy reported among challenge trials compared with field trials, risk models predicting the public health benefits of pre-harvest interventions to reduce zoonotic pathogens in livestock might be best served by field trial results alone.

Preventive Veterinary Medicine, 2010

Using the spatial scan statistic with a Bernoulli model, in a comparison of the two most common c... more Using the spatial scan statistic with a Bernoulli model, in a comparison of the two most common canine uroliths, calcium oxalate (CaOx) and magnesium ammonium phosphate (struvite) we determined whether there was evidence of spatial and/or temporal clustering of each urolith type based on canine submissions from Ontario to the Canadian Veterinary Urolith Centre (CVUC) between 1998 and 2006. During this period, there were 10,478 canine submissions, excluding cases that were identified as recurrent. We were able to georeference approximately 93% of these incident cases. After adjusting for spatial and temporal distributions of dogs based on the demographic risk factors of age, sex, and breed-type, statistically significant spatial and temporal clusters were present for both CaOx and struvite urolith types. A purely temporal struvite cluster occurred between February 10, 1998 and December 20, 2001, whereas, a purely temporal CaOx cluster occurred between September 2, 2005 and December 21, 2006. Hypotheses to explain the spatial clustering of uroliths include variation in the spatial distribution of water hardness, diet-type, access to veterinary care, and the use of surgical versus medical therapies to treat these uroliths. Based on the cluster locations, water hardness was unlikely to explain the spatial difference between the two cluster types whereas variables related to human population density were more consistent with our findings; the CaOx cluster occurred in the highest population density area of Ontario, and the struvite cluster occurred in the lowest population density area of southern Ontario. The temporal struvite cluster at the beginning and CaOx cluster at the end of the study period reflect a similar trend away from struvite towards CaOx urolithiasis among both canines and humans in the developed countries of North America and Europe.

Preventive Veterinary Medicine, 2010

Using the spatial scan statistic with a Bernoulli model, in a comparison of the two most common c... more Using the spatial scan statistic with a Bernoulli model, in a comparison of the two most common canine uroliths, calcium oxalate (CaOx) and magnesium ammonium phosphate (struvite) we determined whether there was evidence of spatial and/or temporal clustering of each urolith type based on canine submissions from Ontario to the Canadian Veterinary Urolith Centre (CVUC) between 1998 and 2006. During this period, there were 10,478 canine submissions, excluding cases that were identified as recurrent. We were able to georeference approximately 93% of these incident cases. After adjusting for spatial and temporal distributions of dogs based on the demographic risk factors of age, sex, and breed-type, statistically significant spatial and temporal clusters were present for both CaOx and struvite urolith types. A purely temporal struvite cluster occurred between February 10, 1998 and December 20, 2001, whereas, a purely temporal CaOx cluster occurred between September 2, 2005 and December 21, 2006. Hypotheses to explain the spatial clustering of uroliths include variation in the spatial distribution of water hardness, diet-type, access to veterinary care, and the use of surgical versus medical therapies to treat these uroliths. Based on the cluster locations, water hardness was unlikely to explain the spatial difference between the two cluster types whereas variables related to human population density were more consistent with our findings; the CaOx cluster occurred in the highest population density area of Ontario, and the struvite cluster occurred in the lowest population density area of southern Ontario. The temporal struvite cluster at the beginning and CaOx cluster at the end of the study period reflect a similar trend away from struvite towards CaOx urolithiasis among both canines and humans in the developed countries of North America and Europe.

Preventive Veterinary Medicine, 2011

Observational studies in pre-harvest food safety may be useful for identifying risk factors and f... more Observational studies in pre-harvest food safety may be useful for identifying risk factors and for evaluating potential mitigation strategies to reduce foodborne pathogens. However, there are no structured reporting guidelines for these types of study designs in livestock species. Our objective was to evaluate the reporting of observational studies in the pre-harvest food safety literature using guidelines modified from the human healthcare literature. We identified 100 pre-harvest food safety studies published between 1999 and 2009. Each study was evaluated independently by two reviewers using a structured checklist. Of the 38 studies that explicitly stated the observational study design, 27 were described as cross-sectional studies, eight as case-control studies, and three as cohort studies. Study features reported in over 75% of the selected studies included: description of the geographic location of the studies, definitions and sources of data for outcomes, organizational level and source of data for independent variables, description of statistical methods and results, number of herds enrolled in the study and included in the analysis, and sources of study funding. However, other features were not consistently reported, including details related to eligibility criteria for groups (such as barn, room, or pen) and individuals, numbers of groups and individuals included in various stages of the study, identification of primary outcomes, the distinction between putative risk factors and confounding variables, the identification of a primary exposure variable, the referent level for evaluation of categorical variable associations, methods of controlling confounding variables and missing variables, model fit, details of subset analysis, demographic information at the sampling unit level, and generalizability of the study results. Improvement in reporting of observational studies of pre-harvest food safety will aid research readers and reviewers in interpreting and evaluating the results of such studies.

American Journal of Veterinary Research, 2010

Impacts • Beef cattle harbour Escherichia coli O157 in their faeces and on their hides. E. coli O... more Impacts • Beef cattle harbour Escherichia coli O157 in their faeces and on their hides. E. coli O157 causes serious illness in humans but no illness in beef cattle. • Faecal E. coli O157 can contaminate the environment during the pre-harvest stage of production or the carcass at the processing stage. • Direct-fed microbials fed to beef cattle during the growing period are efficacious in reducing faecal shedding of E. coli O157. Summary Human illness due to infections with Escherichia coli O157 is a serious health concern. Infection occurs through direct contact with infected animals or their fae-ces, through contaminated food or water and/or through person-to-person transmission. A reduction in faecal E. coli O157 shedding in cattle might reduce the burden of human infections. We used systematic review and meta-analysis to assess the efficacy of direct-fed microbials (DFM), compared with placebo or no treatment, fed during the pre-harvest stage of production in reducing faecal E. coli O157 shedding in beef cattle during field trials. Four electronic databases, Nebraska Beef Reports and review article reference lists were searched. A total of 16 publications assessing faecal shedding at the end of the trial and/or throughout the trial period were included. The majority of publicly disseminated trials evaluated the prevalence of E. coli O157 faecal shedding; only two evaluated the concentration of organisms in faeces. The prevalence of faecal E. coli O157 shedding in cattle is significantly reduced by DFM treatments (summary effect size for all DFM – OR = 0.46; CI = 0.36–0.60). The DFM combination Lactobacillus aci-dophilus (NP51) and Propionibacterium freudenreichii (NP24) was more effica-cious in reducing the prevalence of faecal E. coli O157 shedding at the time of harvest and throughout the trial period compared with the group of other DFM, although this difference was not statistically significant. Furthermore, we found that the combination [NP51 and NP24] treatment was more efficacious in reducing the prevalence of faecal E. coli O157 shedding at the time of harvest and throughout the trial period when fed at the dose of 10 9 CFU/animal/day than any lesser amount, although this difference was not statistically significant. Feeding beef cattle DFM during the pre-harvest stage of production reduces the prevalence of E. coli O157 faecal shedding and might effectively reduce human infections.

Reducing zoonotic pathogens in food animals prior to harvest will reduce the pathogen burden that... more Reducing zoonotic pathogens in food animals prior to harvest will reduce the
pathogen burden that enters the food chain and the environment. Consequently,
the burden of enteric illness in humans may be reduced. Evaluating interventions
to reduce a pathogen in animals often begins with challenge trials, in which animals
are deliberately exposed to the pathogen under controlled conditions. Challenge
trials are subsequently followed by field trials, also known as randomized
controlled trials, in which the animals are naturally exposed to the pathogen.
Challenge trials can most effectively inform field trials only if they precede field
trials, are robust, internally valid and transparently reported. Using systematic
review and meta-analysis methodology, we examined the pre-harvest food safety
literature for three intervention—pathogen—species combinations: probiotics/
competitive exclusion products in ruminants to reduce Escherichia coli O157
shedding, vaccines in ruminants to reduce E. coli O157 shedding and vaccines in
swine to reduce Salmonella shedding. We examined two outcomes, prevalence of
faecal shedding at the end of the trial and prevalence of faecal shedding throughout
the trial period, to compare challenge trials and field trials. We found that
challenge trials occurred concurrently with field trials, challenge trials suffered
from reporting deficiencies of methodological features, challenge trials tended to
report a more favourable outcome than field trials, and there was some evidence
of publication bias among all three intervention–pathogen–species combinations.
Challenge trials would better serve to inform field trials if they precede field trials,
are methodologically sound, include transparent reporting and are published
regardless of their results. In addition, due to our findings of greater efficacy
reported among challenge trials compared with field trials, risk models predicting
the public health benefits of pre-harvest interventions to reduce zoonotic pathogens
in livestock might be best served by field trial results alone.

Animal Health Research Reviews

Livestock producers are encouraged to reduce the use of antibiotics belonging to classes of medic... more Livestock producers are encouraged to reduce the use of antibiotics belonging to classes of medical importance to humans. We conducted a scoping review on non-antibiotic interventions in the form of products or management practices that could potentially reduce the need for antibiotics in beef and veal animals living under intensive production conditions. Our objectives were to systematically describe the research on this broad topic, identify specific topics that could feasibly support systematic reviews, and identify knowledge gaps. Multiple databases were searched. Two reviewers independently screened and charted the data. From the 13,598 articles screened, 722 relevant articles were charted. The number of relevant articles increased steadily from 1990. The Western European research was dominated by veal production studies whereas the North American research was dominated by beef production studies. The interventions and outcomes measured were diverse. The four most frequent inte...

Animal health research reviews, Jan 11, 2017

Acupuncture has become increasingly popular in veterinary medicine. Within the scientific literat... more Acupuncture has become increasingly popular in veterinary medicine. Within the scientific literature there is debate regarding its efficacy. Due to the complex nature of acupuncture, a scoping review was undertaken to identify and categorize the evidence related to acupuncture in companion animals (dogs, cats, and horses). Our search identified 843 relevant citations. Narrative reviews represented the largest proportion of studies (43%). We identified 179 experimental studies and 175 case reports/case series that examined the efficacy of acupuncture. Dogs were the most common subjects in the experimental trials. The most common indication for use was musculoskeletal conditions, and the most commonly evaluated outcome categories among experimental trials were pain and cardiovascular parameters. The limited number of controlled trials and the breadth of indications for use, outcome categories, and types of acupuncture evaluated present challenges for future systematic reviews or meta-...

Zoonoses and Public Health, 2014

Human illness due to infections with Escherichia coli O157 is a serious health concern. Infection... more Human illness due to infections with Escherichia coli O157 is a serious health concern. Infection occurs through direct contact with infected animals or their faeces, through contaminated food or water and/or through person-to-person transmission. A reduction in faecal E. coli O157 shedding in cattle might reduce the burden of human infections. We used systematic review and meta-analysis to assess the efficacy of direct-fed microbials (DFM), compared with placebo or no treatment, fed during the pre-harvest stage of production in reducing faecal E. coli O157 shedding in beef cattle during field trials. Four electronic databases, Nebraska Beef Reports and review article reference lists were searched. A total of 16 publications assessing faecal shedding at the end of the trial and/or throughout the trial period were included. The majority of publicly disseminated trials evaluated the prevalence of E. coli O157 faecal shedding; only two evaluated the concentration of organisms in faeces. The prevalence of faecal E. coli O157 shedding in cattle is significantly reduced by DFM treatments (summary effect size for all DFM - OR = 0.46; CI = 0.36-0.60). The DFM combination Lactobacillus acidophilus (NP51) and Propionibacterium freudenreichii (NP24) was more efficacious in reducing the prevalence of faecal E. coli O157 shedding at the time of harvest and throughout the trial period compared with the group of other DFM, although this difference was not statistically significant. Furthermore, we found that the combination [NP51 and NP24] treatment was more efficacious in reducing the prevalence of faecal E. coli O157 shedding at the time of harvest and throughout the trial period when fed at the dose of 10(9) CFU/animal/day than any lesser amount, although this difference was not statistically significant. Feeding beef cattle DFM during the pre-harvest stage of production reduces the prevalence of E. coli O157 faecal shedding and might effectively reduce human infections.

Zoonoses and Public Health, 2013

Reducing zoonotic pathogens in food animals prior to harvest will reduce the pathogen burden that... more Reducing zoonotic pathogens in food animals prior to harvest will reduce the pathogen burden that enters the food chain and the environment. Consequently, the burden of enteric illness in humans may be reduced. Evaluating interventions to reduce a pathogen in animals often begins with challenge trials, in which animals are deliberately exposed to the pathogen under controlled conditions. Challenge trials are subsequently followed by field trials, also known as randomized controlled trials, in which the animals are naturally exposed to the pathogen. Challenge trials can most effectively inform field trials only if they precede field trials, are robust, internally valid and transparently reported. Using systematic review and meta-analysis methodology, we examined the pre-harvest food safety literature for three intervention-pathogen-species combinations: probiotics/competitive exclusion products in ruminants to reduce Escherichia coli O157 shedding, vaccines in ruminants to reduce E. coli O157 shedding and vaccines in swine to reduce Salmonella shedding. We examined two outcomes, prevalence of faecal shedding at the end of the trial and prevalence of faecal shedding throughout the trial period, to compare challenge trials and field trials. We found that challenge trials occurred concurrently with field trials, challenge trials suffered from reporting deficiencies of methodological features, challenge trials tended to report a more favourable outcome than field trials, and there was some evidence of publication bias among all three intervention-pathogen-species combinations. Challenge trials would better serve to inform field trials if they precede field trials, are methodologically sound, include transparent reporting and are published regardless of their results. In addition, due to our findings of greater efficacy reported among challenge trials compared with field trials, risk models predicting the public health benefits of pre-harvest interventions to reduce zoonotic pathogens in livestock might be best served by field trial results alone.

Preventive Veterinary Medicine, 2010

Using the spatial scan statistic with a Bernoulli model, in a comparison of the two most common c... more Using the spatial scan statistic with a Bernoulli model, in a comparison of the two most common canine uroliths, calcium oxalate (CaOx) and magnesium ammonium phosphate (struvite) we determined whether there was evidence of spatial and/or temporal clustering of each urolith type based on canine submissions from Ontario to the Canadian Veterinary Urolith Centre (CVUC) between 1998 and 2006. During this period, there were 10,478 canine submissions, excluding cases that were identified as recurrent. We were able to georeference approximately 93% of these incident cases. After adjusting for spatial and temporal distributions of dogs based on the demographic risk factors of age, sex, and breed-type, statistically significant spatial and temporal clusters were present for both CaOx and struvite urolith types. A purely temporal struvite cluster occurred between February 10, 1998 and December 20, 2001, whereas, a purely temporal CaOx cluster occurred between September 2, 2005 and December 21, 2006. Hypotheses to explain the spatial clustering of uroliths include variation in the spatial distribution of water hardness, diet-type, access to veterinary care, and the use of surgical versus medical therapies to treat these uroliths. Based on the cluster locations, water hardness was unlikely to explain the spatial difference between the two cluster types whereas variables related to human population density were more consistent with our findings; the CaOx cluster occurred in the highest population density area of Ontario, and the struvite cluster occurred in the lowest population density area of southern Ontario. The temporal struvite cluster at the beginning and CaOx cluster at the end of the study period reflect a similar trend away from struvite towards CaOx urolithiasis among both canines and humans in the developed countries of North America and Europe.

Preventive Veterinary Medicine, 2010

Using the spatial scan statistic with a Bernoulli model, in a comparison of the two most common c... more Using the spatial scan statistic with a Bernoulli model, in a comparison of the two most common canine uroliths, calcium oxalate (CaOx) and magnesium ammonium phosphate (struvite) we determined whether there was evidence of spatial and/or temporal clustering of each urolith type based on canine submissions from Ontario to the Canadian Veterinary Urolith Centre (CVUC) between 1998 and 2006. During this period, there were 10,478 canine submissions, excluding cases that were identified as recurrent. We were able to georeference approximately 93% of these incident cases. After adjusting for spatial and temporal distributions of dogs based on the demographic risk factors of age, sex, and breed-type, statistically significant spatial and temporal clusters were present for both CaOx and struvite urolith types. A purely temporal struvite cluster occurred between February 10, 1998 and December 20, 2001, whereas, a purely temporal CaOx cluster occurred between September 2, 2005 and December 21, 2006. Hypotheses to explain the spatial clustering of uroliths include variation in the spatial distribution of water hardness, diet-type, access to veterinary care, and the use of surgical versus medical therapies to treat these uroliths. Based on the cluster locations, water hardness was unlikely to explain the spatial difference between the two cluster types whereas variables related to human population density were more consistent with our findings; the CaOx cluster occurred in the highest population density area of Ontario, and the struvite cluster occurred in the lowest population density area of southern Ontario. The temporal struvite cluster at the beginning and CaOx cluster at the end of the study period reflect a similar trend away from struvite towards CaOx urolithiasis among both canines and humans in the developed countries of North America and Europe.

Preventive Veterinary Medicine, 2011

Observational studies in pre-harvest food safety may be useful for identifying risk factors and f... more Observational studies in pre-harvest food safety may be useful for identifying risk factors and for evaluating potential mitigation strategies to reduce foodborne pathogens. However, there are no structured reporting guidelines for these types of study designs in livestock species. Our objective was to evaluate the reporting of observational studies in the pre-harvest food safety literature using guidelines modified from the human healthcare literature. We identified 100 pre-harvest food safety studies published between 1999 and 2009. Each study was evaluated independently by two reviewers using a structured checklist. Of the 38 studies that explicitly stated the observational study design, 27 were described as cross-sectional studies, eight as case-control studies, and three as cohort studies. Study features reported in over 75% of the selected studies included: description of the geographic location of the studies, definitions and sources of data for outcomes, organizational level and source of data for independent variables, description of statistical methods and results, number of herds enrolled in the study and included in the analysis, and sources of study funding. However, other features were not consistently reported, including details related to eligibility criteria for groups (such as barn, room, or pen) and individuals, numbers of groups and individuals included in various stages of the study, identification of primary outcomes, the distinction between putative risk factors and confounding variables, the identification of a primary exposure variable, the referent level for evaluation of categorical variable associations, methods of controlling confounding variables and missing variables, model fit, details of subset analysis, demographic information at the sampling unit level, and generalizability of the study results. Improvement in reporting of observational studies of pre-harvest food safety will aid research readers and reviewers in interpreting and evaluating the results of such studies.

American Journal of Veterinary Research, 2010

Impacts • Beef cattle harbour Escherichia coli O157 in their faeces and on their hides. E. coli O... more Impacts • Beef cattle harbour Escherichia coli O157 in their faeces and on their hides. E. coli O157 causes serious illness in humans but no illness in beef cattle. • Faecal E. coli O157 can contaminate the environment during the pre-harvest stage of production or the carcass at the processing stage. • Direct-fed microbials fed to beef cattle during the growing period are efficacious in reducing faecal shedding of E. coli O157. Summary Human illness due to infections with Escherichia coli O157 is a serious health concern. Infection occurs through direct contact with infected animals or their fae-ces, through contaminated food or water and/or through person-to-person transmission. A reduction in faecal E. coli O157 shedding in cattle might reduce the burden of human infections. We used systematic review and meta-analysis to assess the efficacy of direct-fed microbials (DFM), compared with placebo or no treatment, fed during the pre-harvest stage of production in reducing faecal E. coli O157 shedding in beef cattle during field trials. Four electronic databases, Nebraska Beef Reports and review article reference lists were searched. A total of 16 publications assessing faecal shedding at the end of the trial and/or throughout the trial period were included. The majority of publicly disseminated trials evaluated the prevalence of E. coli O157 faecal shedding; only two evaluated the concentration of organisms in faeces. The prevalence of faecal E. coli O157 shedding in cattle is significantly reduced by DFM treatments (summary effect size for all DFM – OR = 0.46; CI = 0.36–0.60). The DFM combination Lactobacillus aci-dophilus (NP51) and Propionibacterium freudenreichii (NP24) was more effica-cious in reducing the prevalence of faecal E. coli O157 shedding at the time of harvest and throughout the trial period compared with the group of other DFM, although this difference was not statistically significant. Furthermore, we found that the combination [NP51 and NP24] treatment was more efficacious in reducing the prevalence of faecal E. coli O157 shedding at the time of harvest and throughout the trial period when fed at the dose of 10 9 CFU/animal/day than any lesser amount, although this difference was not statistically significant. Feeding beef cattle DFM during the pre-harvest stage of production reduces the prevalence of E. coli O157 faecal shedding and might effectively reduce human infections.

Reducing zoonotic pathogens in food animals prior to harvest will reduce the pathogen burden that... more Reducing zoonotic pathogens in food animals prior to harvest will reduce the
pathogen burden that enters the food chain and the environment. Consequently,
the burden of enteric illness in humans may be reduced. Evaluating interventions
to reduce a pathogen in animals often begins with challenge trials, in which animals
are deliberately exposed to the pathogen under controlled conditions. Challenge
trials are subsequently followed by field trials, also known as randomized
controlled trials, in which the animals are naturally exposed to the pathogen.
Challenge trials can most effectively inform field trials only if they precede field
trials, are robust, internally valid and transparently reported. Using systematic
review and meta-analysis methodology, we examined the pre-harvest food safety
literature for three intervention—pathogen—species combinations: probiotics/
competitive exclusion products in ruminants to reduce Escherichia coli O157
shedding, vaccines in ruminants to reduce E. coli O157 shedding and vaccines in
swine to reduce Salmonella shedding. We examined two outcomes, prevalence of
faecal shedding at the end of the trial and prevalence of faecal shedding throughout
the trial period, to compare challenge trials and field trials. We found that
challenge trials occurred concurrently with field trials, challenge trials suffered
from reporting deficiencies of methodological features, challenge trials tended to
report a more favourable outcome than field trials, and there was some evidence
of publication bias among all three intervention–pathogen–species combinations.
Challenge trials would better serve to inform field trials if they precede field trials,
are methodologically sound, include transparent reporting and are published
regardless of their results. In addition, due to our findings of greater efficacy
reported among challenge trials compared with field trials, risk models predicting
the public health benefits of pre-harvest interventions to reduce zoonotic pathogens
in livestock might be best served by field trial results alone.