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Expanded swine disease report tracks state-based trends

TAGS: Swine
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SHIC-funded swine disease report expands to include state-by-state pathogen trends.

The Swine Health Information Center (SHIC) funds the "Domestic Swine Disease Monitoring Report" (DSDMR), a collaborative project among multiple veterinary diagnostic laboratories (VDLs) to aggregate swine diagnostic data.

Beginning in June 2020, DSDMR will include specific state-by-state pathogen trends, according to SHIC executive director Dr. Paul Sundberg. With the report, veterinarians and producers will know if rates of porcine epidemic diarrhea virus, porcine reproductive and respiratory syndrome virus, Mycoplasma hyopneumoniae or potentially other pathogens are moving up or down in the states analyzed. Identifying these trends is just the first step to further analysis of the data to understand the reasons for the trends and, thus, to help manage them, Sundberg said.

Prepared by Drs. Daniel Linhares and Giovani Trevisan at Iowa State University, DSDMR describes dynamics of pathogen detection by VDL-performed assays over time, specimen, age group and geographical area. Data included is from the Iowa State University VDL, South Dakota State University Animal Disease Research & Diagnostic Laboratory, University of Minnesota VDL and Kansas State University VDL.

This project includes states where DSDMR participant VDLs are located and those having a swine inventory equal to or greater than 2 million pigs, SHIC said.

The report authors are using the percentage of polymerase chain reaction (PCR)-positive submissions by state and then applying smoothing models to forecast results for a 12-month period, SHIC explained. This report uses predicted values of percentage-positive results by PCR (by pathogen, month and state), which are then subtracted from observed values, generating residue values. Then, residues are scanned by an exponential weighted moving average (EWMA) model to monitor and generate changes from the expected baseline.

The baseline and monitoring are constructed based on each state's data, with no comparison across states, SHIC said.

EWMA findings are reported as changes in standard deviations from the expected baseline. Changes from the baseline are reported as:

  • No change when results were within two deviations from the baseline;
  • Changes between two and three deviations from the baseline, and
  • Changes of at least three deviations above or below the baseline.

Information for each state regarding the change from the baseline, the number of total positive submissions and percent of positive results were recovered from the models and transferred to Microsoft Power BI for geographic visualization. The dashboards for state-by-state pathogen trending can be accessed on the SHIC website at DSDMR or by visiting Iowa State University's site for the Swine Disease Reporting System (SDRS).

As the world deals with the COVID-19 pandemic, SHIC continues to focus efforts on prevention, preparedness and response to novel and emerging swine diseases for the benefit of U.S. swine health. As a conduit of information and research, SHIC encourages the sharing of its publications and research.

SHIC is funded by America's pork producers to fulfill its mission to protect and enhance the health of the U.S. swine herd. For more information, visit www.swinehealth.org.

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