Evaluation of the Risk of PRRSV Transmission via Ingestion of Muscle from Persistently Infected Pigs

Abstract

The objectives of this experiment were to determine how long porcine reproductive and respiratory syndrome virus (PRRSV) could be detected in muscle tissues of experimentally infected pigs and to evaluate the transmissibility of PRRSV to pigs via ingestion of quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR)-positive muscle tissues. Serum, lymphoid tissues, and muscle (M. longissimus dorsi) samples were collected from 135 pigs (89 PRRSV-inoculated pigs and 46 negative control). Between 28 and 202 days post-inoculation, 13 of 89 (14.6%) muscle samples were positive by qRT-PCR. Among these 13, PRRSV was isolated from four of the 13 corresponding serum samples and three of 13 lymphoid tissue samples. In addition, infectious virus was detected in lymphoid tissue homogenates of six of 13 pigs by intramuscular bioassay. Swine transmissibility studies were performed by feeding thirteen 3-week-old PRRSV-naive pigs (recipient pigs) qRT-PCR-positive muscle and then monitoring recipients for evidence of PRRSV viremia by qRT-PCR. No transmission of PRRSV to recipient pigs via consumption of muscle samples was observed. These data suggested that qRT-PCR detected non-infectious PRRSV in pig meat and/or PRRSV is not highly transmissible to susceptible pigs via consumption of PRRSV-contaminated meat.

Porcine reproductive and respiratory syndrome virus modifies innate immunity and alters disease outcome in pigs subsequently infected with porcine respiratory coronavirus: implications for respiratory viral co-infections

“…Lung homogenates from each pig were tested by real-time PCR for PRRSV and PRCV RNA quantification as previously described (Jung et al , 2007; Molina et al , 2008). For PRRSV, all samples were tested at the Animal Disease Research and Diagnostic Laboratory, Veterinary Science Department, South Dakota State University, USA.…”

Fresh Pork and Porcine Reproductive and Respiratory Syndrome Virus: Factors Related to the Risk of Disease Transmission

“…Studies on the infectivity of PRRS virus-infected pork are limited, and only four studies have been published (van der Linden et al, 2003a;Magar and Larochelle, 2004;Cano et al, 2007;Molina et al, 2009). The earliest work done in the Netherlands used twenty-four 8-week-old-pigs as sources of infected muscle for an oral exposure trial (van der Linden et al, 2003a).…”

“…In a large study conducted in the United States, eighty‐nine 14‐day‐old piglets were inoculated with 10 4 TCID 50 of PRRS virus strain MN‐184 by intramuscular injection (Molina et al., ). An additional 56 piglets were sham‐inoculated with MEM by intramuscular injection.…”

The spread of pathogens through trade in pig meat: overview and recent developments

“…However, Molina et al (29) further investigated the transmissibility of PRRS by ingestion of meat from infected animals, and reported that, while 13 of 89 muscle samples (14.6%) were positive for PRRS by RT-PCR at various intervals post infection, in none of these 13 cases did the feeding of 100 g to 200 g of meat to individually housed recipient pigs result in infection.…”