SHIC-Funded Study Evaluates Tongue Tip Fluids for Pathogen Monitoring in Nursery and Grow-Finish Pigs

The Swine Health Information Center funded a study to evaluate tongue tip fluids, a sample type more frequently used in breeding herds, as a potential tool for pathogen surveillance in nursery and grow-finish phases. The study evaluated PRRSV and IAV detection in oral fluids compared to tongue tip fluids using PCR in weekly samples from wean-to-market pigs and assessed the likelihood of successful PRRSV ORF-5 sequencing across the two sample types. Led by Drs. Gustavo Silva and Onyekachukwu Henry Osemeke of Iowa State University, the study found that tongue tip fluids offer a comparable and cost-effective alternative to oral fluids for the detection of PRRSV and IAV by qPCR in growing pig herds when mortalities are present.

Find the study industry summary here.

PRRSV and IAV are two swine pathogens that significantly impact the health and productivity of post-weaning pigs. While oral fluids are widely used for monitoring these viruses, post-mortem tongue tip fluids represent a cost-effective alternative with potential advantages for viral detection in mortalities. Surveillance programs in growing pig herds are generally not as robust as those in breeding herds. Consequently, all sample types considered for use in post-weaning pigs require evaluation for ease of collection, cost-effectiveness, sensitivity, and reliability of surveillance results under conditions of sample pooling.

Three objectives were evaluated in this study, including: 1) to compare the detection of PRRSV and IAV using qPCR in weekly oral fluids and tongue tip fluids from wean-to-market pigs, 2) to assess the likelihood of successful PRRSV ORF-5 sequencing across the two sample types, 3) to assess the effect of pooling tongue tip fluids on PCR detection of PRRSV.

To complete these aims, three groups of pigs from two production systems were tested for PRRSV and IAV from weaning until market. Two groups (A and B) were sourced from PRRSV-positive stable sow farms, while Group C was from a farm weaning positive pigs. Groups B and C received a PRRSV-modified live virus vaccine at weaning. Weekly, oral fluids from six pens and tongue tip fluids were tested for PRRSV and IAV using qPCR.