Detection of PRRS seroconversion and persisting antibody titers in swine following controlled infection during a long-term study

摘要

The arterivirus that causes Porcine Reproductive and Respiratory Syndrome (PRRS) was identified in the early 1990s and has since become endemic within swine production. PRRS virus causes significant economic impact to the pork industry due to herd losses. Therefore, methods of optimal detection, maintenance, and elimination have been sought vigorously by researchers to prevent herd devastation. PRRS virus can spread rapidly by contact with an infected pig. The temporal pattern of PRRS viral infectionis characterized by the early post-infection period where serum antibodies can be detected between 7-9 days post infection (dpi), immediately followed by an acute viremic phase during which tissues display a high viral load. The acute phase can extend for 1 month after which the late infectious stage involves a low, yet persistent, viral tissue load and is thought to eventually be cleared from the animal by 150dpi. While the virus has the ability to persist in the pig even after clinical signs of infection subside, it remains unclear the role of this persistence in causing further outbreaks. The virus has been detected in swine tissues as late as 157 dpi. Its potential to infect other herds in the absence of clinical symptoms illustrates the need fora screening method to ensure persisting infection is detected to avoid exposure to naive pigs.