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.
This week, we are sharing part 2 of the report on the role of the environment and the lactating sow in PRRSV outbreak. You may find part 1 of the report here.
Key Points:
- PRRS virus can be detected in the environment of the farrowing house (surfaces and air) and on the udder skin of lactating sows. However, PRRSV detection in the environment decreases as time after an outbreak increases.
- PRRSV was not detected in the environment after 4 months of an outbreak
- Role of environmental PRRSV in the transmission of the disease is still unknown.
In this study, udder and surface wipes as well as particle deposition wipes were collected both at processing and at weaning, starting 2 weeks after the PRRSV outbreak.
Results showed that PRRSV was detected at processing up to 14 weeks after the outbreak in surfaces and udder skin of lactating sows. At weaning, PRRSV was detected up to 17 weeks post-outbreak using udder skin wipes. The number of positive samples decreased over time and the Ct values of the positive samples increased over time indicating a decrease in infection load overtime. Detection of airborne particle deposition positive samples followed a similar pattern to those of the crate surfaces and udder wipes. Virus could be isolated and sequenced from all sample types.
Udder skin and environment may play a role in the transmission and maintenance of PRRSV in piglets in breeding herds; however further research is needed to validate this observation.