Progress 06/15/17 to 06/14/22

Outputs
Target Audience:The target audience consists of scientists involved in investigating the mechanisms of virus virulence and the synergistic effect observed during PRRSV-bacterial co-infections that result in exacerbated pneumonia and comprise one version of the syndrome known as porcine respiratory disease complex (PRDC). Additionally, swine veterinarians and pork producers would be interested in alternative therapeutic interventions for disease control that would lessen the need to use antimicrobials. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The personnel involved in the project gained proficiency in the methods and processes to assess the pathogenicity of a microbe. How have the results been disseminated to communities of interest?Abstracts were presented at the 2018 and 2021 CRWAD meeting in Chicago in the form of a poster (2018) and oral (2019) presentations. A manuscript was published in a peer-reviewed journal. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? The goal of this project is to identify novel targets for alternative therapeutic intervention for disease reduction in swine afflicted with a PRRSV-bacterial co-infection as an alternative to antimicrobial therapy, an aim of priority code A1221. Accordingly, live animal studies were performed to test the ability of direct fed microbials (DFM) to mitigate the pathogenic synergy between PRRS virus andS.choleraesuis. Analysis of the data obtained revealed that provision of DFM in the diet of weaner pigs reduced both the rate and magnitude of Salmonella colonization of the lung and lung pathology. The data indicate that aBacillus-based DFM can exert a beneficial health effect distally to the gastrointestinal tract, manifested by an increased resistance to viral infection in the respiratory tract. Analyses of blood and tissue samples were performed to obtain a glimpse of the mechanism responsible for this beneficial effect. These analyses included the measurement of changes in inflammatory cytokine production in the lung, as well as changes in the gene expression levels in blood cells of >30 immune related genes such as NOD-2 and TREM-1.

Publications

• Type: Journal Articles Status: Published Year Published: 2022 Citation: Zuckermann FA, Husmann R, Chen W, Roady P, Pfeiff J, Leistikow KR, Duersteler M, Son S, King MR, Augspurger NR. Bacillus-Based Direct-Fed Microbial Reduces the Pathogenic Synergy of a Coinfection with Salmonella enterica Serovar Choleraesuis and Porcine Reproductive and Respiratory Syndrome Virus. Infect Immun. 2022 Apr 21;90(4):e0057421. doi: 10.1128/iai.00574-21. Epub 2022 Mar 7. PMID: 35254092; PMCID: PMC9022502.

Progress 06/15/20 to 06/14/21

Outputs
Target Audience:The target audience consists of scientists involved in investigating the mechanisms of virus virulence and the synergistic effect observed during PRRSV-bacterial co-infections that result in exacerbated pneumonia and comprise one version of the syndrome known as porcine respiratory disease complex (PRDC). Additionally, swine veterinarians and pork producers would be interested in alternative therapeutic interventions for disease control that would lessen the need to use of antimicrobials. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?An abstract was submitted for presentation at the 2021 CRWAD meeting in Chicago. It will be communicated as an oral presentation. A manuscript has been submitted for publication at a peer-reviewed journal. What do you plan to do during the next reporting period to accomplish the goals?A manuscript was submitted for publication to a peer-reviewed journal and is under review. We hope that it will be accepted without major revisions. However, in the event that changes are requested by the reviewers will work to address the criticism and make every effort to have the manuscript published.

Impacts
What was accomplished under these goals? The goal of this project is to identify novel targets for alternative therapeutic intervention for disease reduction in swine afflicted with a PRRSV-bacterial co-infection as an alternative to antimicrobial therapy, an aim of priority code A1221. Accordingly, live animal studies were performed to test the ability of direct fed microbials (DFM) to mitigate the pathogenic synergy between PRRS virus andS.choleraesuis. Analysis of the data obtained revealed that provision of DFM in the diet of weaner pigs reduced both the rate and magnitude of Salmonella colonization of the lung and lung pathology. The data indicate that aBacillus-based DFM can exert a beneficial health effect distally to the gastrointestinal tract, manifested by an increased resistance to viral infection in the respiratory tract. Analyses of blood and tissue samples were performed to obtain a glimpse of the mechanism responsible for this beneficial effect. These analyses included the measurement of changes in inflammatory cytokine production in the lung, as well as changes in the gene expression levels in blood cells of >30 immune related genes such as NOD-2 and TREM-1.

Publications

• Type: Journal Articles Status: Submitted Year Published: 2021 Citation: To be determined

Progress 06/15/19 to 06/14/20

Outputs
Target Audience:The target audience consists of scientists involved in investigating the mechanisms of virus virulence and the synergistic effect observed during PRRSV-bacterial co-infections that result in exacerbated pneumonia and comprise one version of the syndrome known as porcine respiratory disease complex (PRDC). Additionally, swine veterinarians and pork producers would be interested in alternative therapeutic interventions for disease control that would lessen the need to use antimicrobials. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?A draft of a manuscript describing the results that have been generated so far has been prepared. Once the ongoing laboratory testing of blood and tissue samples is completed, the data will be analyzed and graphed. Once this is completed, a final version of a manuscript will be submitted for publication in a peer-reviewed journal

Impacts
What was accomplished under these goals? Analysis of the data revealed that provision of DFM in the diet of weaner pigs reduced both the rate and magnitude of Salmonella colonization of the lung and lung pathology. The data indicate that aBacillus-based DFM can exert a beneficial health effect distally to the gastrointestinal tract, manifested by an increased resistance to viral infection in the respiratory tract. Further analyses of blood and tissue samples are currently being performed to obtain a glimpse of the mechanism responsible for this beneficial effect. These analyses include the measurement of changes in inflammatory cytokine production in the lung, and changes in blood cells of the expression levels of immune related genes such as NOD-2 and TREM-1.

Publications

Progress 06/15/18 to 06/14/19

Outputs
Target Audience:The target audience consists of scientists involved in investigating the mechanisms of virus virulence and the synergistic effect observed during PRRSV-bacterial co-infections that result in exacerbated pneumonia and comprise one version of the syndrome known as porcine respiratory disease complex (PRDC). Additionally, swine veterinarians and pork producers would be interested in alternative therapeutic interventions for disease control that would lessen the need to use antimicrobials. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The personnel involved in the project gained greater proficiency in the methods and processes to conduct this project. How have the results been disseminated to communities of interest?An abstract describing the work will be presented at an international meeting in 2020, and a manuscript is being written, which will be submitted for publication by April of 2020. What do you plan to do during the next reporting period to accomplish the goals?Experiments will be performed to ascertain the mechanism by which direct fed microbials mitigate the pathogenicity of PRRS virus and/or Salmonella.

Impacts
What was accomplished under these goals? During the previous reporting period, we established the conditions to experimentally trigger the pathogenic synergy between PRRS virus andSalmonellacholeraesuisin swine. These conditions consistently resulted in a 100% rate of colonization of the ileocecal lymph node with Salmonella. Co-infection with PRRS virus resulted in an increased rate of colonization of the lung by Salmonella and worseningpneumonia. There is increasing evidence supporting a beneficial role of the gut flora in modulating innate immunity, which could influence the ability of the host to resist a microbial challenge. Hence, we explored the ability of direct fed microbials (DFM) to mitigate the pathogenic synergy between PRRS virus andS.choleraesuis.Provision of DFM in the diet of weaner pigs reduced both the rate and magnitude of Salmonella colonization of the lung and associated lymphoid tissues. In addition, there was a reduction in the extent and severity of lung pathology, as well as in the severity of the Salmonella-induced exudative peritonitis, as indicated by a reduced amount of fibrinous ascites production. At necropsy, concentrations of IL-1 and IL-8 were increased in lung lavage fluids collected from DFM-supplemented pigs, accompanied by increased expression in the blood cells of signaling molecules known to be involved in modulating inflammation.Overall, the results suggest that DFM can exert a mitigating influence on the pathogenicity of microbes that target the respiratory system.

Publications

Progress 06/15/17 to 06/14/18

Outputs
Target Audience:The target audience consists of scientists involved in investigating the mechanisms of virus virulence and the synergistic effect observed during PRRSV-bacterial co-infections that result in exacerbated pneumonia and comprise one version of the syndrome known as porcine respiratory disease complex (PRDC). Additionally, swine veterinarians and pork producers would be interested in alternative therapeutic interventions for disease control that would lessen the need to useantimicrobials. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The personnel involved in the projectgained greater proficiency in the methods and processes to conduct this project. How have the results been disseminated to communities of interest?A poster describing the work was presented during thereporting periodat the 2018 Conference of Research Workers Animal Diseases meeting in Chicago. What do you plan to do during the next reporting period to accomplish the goals?Experiments to test the effect of the IRE1 inhibitor drug on the pathogenic synergy between PRRS virus and Salmonella will be performed.

Impacts
What was accomplished under these goals? As the first step we established the conditions to consistently trigger experimentally the known pathogenic synergy between PRRSV and Salmonella choleraesuis. This was accomplished by infecting 5-6 weeks-old swine with 109 colony forming units of S. choleraesuis var. Kunzendorf by oral gavage, followed three days later by an intranasal inoculation with wild-type type II genotype PRRSV. Under these conditions, Salmonella was recovered from the ileocecal lymph node from every animal inoculatednine days earlier with the bacteria. The rate of Salmonella isolation from either the lung and/or the bronchial lymph node from animals inoculated with both PRRSV and Salmonella (10 of 11), was 2.5 times higher than in animals inoculated only with the bacteria (4 of 11). The higher rate of bacterial isolation was associated with an increased severity of lung pathology, characterized by interstitial pneumonia combined with bronchopneumonia. We have established the conditions that consistently establish an intestinal infection of swine with S. choleraesuis with a 100% rate, that synergizes with PRRSV, resulting in an increased rate of lung colonization by the bacteria and a more severe pneumonia.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Zuckermann, F. 2018. A model to study the mechanism of pathogenic synergy between PRRS virus and a respiratory bacterial infection. CRWAD 2018. Chicago, Illinois.