Evaluation of Meat Juice as Sample Matrix for the Detection of Foot-and-Mouth Disease Virus (FMDV) Antigen and Nucleic Acids as Well as Antibodies to FMDV

Particular specimens are usually required for foot-and-mouth disease virus (FMDV) testing. These samples include liquid removed from blisters caused by FMDV (vesicular fluid), pieces of skin recovered from blisters that have burst open (epithelial tags), swabs, serum and other specimens taken from live animals. However, there might be situations when these routine specimens are not available and alternatives may be required. Meat juice (MJ) can be collected from meat that has already been sent to market or from meat imported illegally and tested for FMDV. Meat juice is the liquid that comes out of meat after the meat has been frozen and then defrosted a few times. In this project we wanted to demonstrate that MJ can be used for FMDV detection. Meat was collected from pigs experimentally infected with FMDV. Meat juice was recovered from this meat, ribonucleic acid (RNA) was extracted from the MJ and tested for the presence of FMDV by real-time reverse transcriptase polymerase chain reactions (RRT-PCR) using the National Centre for Foreign Animal Disease (NCFAD) protocol in parallel with the US National Animal Health Laboratory Network (NAHLN) FMDV RRT-PCR and TetraCore (commercial) FMDV RRT-PCR detection kit. Meat juice was also tested by lateral flow strip tests (LFST) for detecting specific proteins (antigens) found on the surface of FMDV. All 3 RRT-PCR assays detected FMDV RNA in MJ from pigs infected with either FMDV serotype A, O, SAT2 or ASIA1. In all cases, FMDV genome detection in sera was short-lived compared to MJ which lasted up to 21 days after infection in some cases. LFSTs detected FMDV antigen in MJ in the early days following infection (days 1 – 9). Furthermore, this study assessed MJ for detection of antibodies to proteins on the surface of FMDV using tests available at the NCFAD. Antibodies to FMDV were detected in MJ from experimentally infected pigs in similar patterns to antibody detection in sera tested in parallel. All this data shows that MJ is a good sample type for FMDV nucleic acid and antigen detection, as well as detection of antibodies to proteins on the surface of FMDV. Therefore, in the absence of traditional samples, MJ can be used for FMDV testing. In addition, if animals are slaughtered/euthanized, MJ can be collected alongside other specimens for FMDV testing.