PRRS Strains Impacting Herds in U.S. and Spain

Porcine reproductive and respiratory syndrome (PRRS) is constantly evolving. New strains continue to impact pork producers in the U.S. and worldwide. However, two strains are seeing increased prevalence in the U.S. and Spain, including the PRRS virus L1C variant of RFLP 1-4-4 and PRRS virus L1C 1-2-4 in the U.S., and Rosalia, a PRRSV-1 strain with increased virulence in Spain.

Consequences in Spain are deadly, with more than 18 million pigs impacted by Rosalia. This strain results in abortion storms in sow herds, sow mortality, stillbirths, suckling piglet mortality and decreased feed conversion rates. The country only has 34 million pigs.

In the U.S., only 421 detections of the L1C Variant RFLP 1-2-4 have been confirmed from 2009 to 2021. In 2022, there were more than 260 confirmed cases. Pork industry leaders continue to emphasize biosecurity in eastern states to prevent the introduction into herds.

Read more on PRRS in pigs here.