Morrison Swine Health Monitoring Project Incidence Year 2022 / 2023 Annual Summary

This is our Friday rubric: every week a new Science Page from the Bob Morrison’s Swine Health Monitoring Project. The previous editions of the science page are available on our website.

The 2022-2023 MSHMP incidence year again brought us unexpected events and chances to learn. We were able to meet these challenges because you, as an MSHMP participant, continue to share your data. We would like to provide a general update and summary of where we are at this point.

Disease incidence monitoring

PRRSv – The 2022-2023 PRRS epidemic followed the usual onset date in November. Interestingly, the cumulative incidence decreased from the previous years as it ended in 20.8%, which is the lowest incidence over the 14-year monitoring period. On the other hand, a third of the breeding herds in our project remain in an unstable status; however, we were happy to see that approximately 5.2% of the herds were stable without continuous exposure of gilts or sows (e.g., AASV status 2) indicating that producers/veterinarians are taking these herds back to naive.

PEDv – Compared to the previous season a decrease was seen. There were 2 smaller epidemics than in the previous year. The main one started earlier than expected and the second one occurred at a time when no activity occurs usually. Unfortunately, 25% (17/68) of the herds reporting at least one break during the 2022/2023 season had gone through another break the previous year. 

Senecavirus – Throughout the 2022/2023 season, Senecavirus generated two important signals in that occurrence increased during the expected season (i.e., summer) but also during the spring. The magnitude of both events was higher than observed in the previous two years. 

Prospective monitoring of PRRSv

We continue to monitor the Lineage 1C 1-4-4 PRRS virus variant, as well as the emergence of new variants. Although the number of L1C144 variant sequences detected can seem high at times, we would like to remind participants that the number of new sites affected is substantially lower than the count of sequences. However, we still observed increased transmission during spring. The MSHMP PRRS sequence data are also playing a key role in the evaluation of the practicality of PRRS variant classifications. 

TEROW (The Early Regional Occurrence Warning project)

As a complement to our preparedness and monitoring efforts, the TEROW project was launched in 2022/2023. A total of 11 companies have joined and are receiving weekly updates on their breeding herd regional risks. We hope to continue to add more participants to this project.

We would like to thank all MSHMP participants and collaborating organizations for their unwavering trust, valuable feedback, and financial support from SHIC. We will be sending out a calendar invite for our MSHMP participant meeting during the 2023 Leman Conference, we hope to see you in September.


The MSHMP Team

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