Oral Fluid Testing for Efficient PEDV Surveillance and Control

June 10, 2015 — 

The project was to determine if oral fluids can be a convenient sample option to detect PEDV and/or virus-specific antibody, and assess its utility for on-farm testing and monitoring. The study was conducted in both experimental and field conditions in which pig fecal swab and pen-based oral fluid samples were collected for viral testing. Serum samples were collected from experimentally infected pigs to assess oral fluid’s diagnostic utility. Polymerase chain reaction (PCR) results on the fecal swab and oral fluid samples from the challenged pigs showed good correlation regarding viral shedding. Antibody level in oral fluids was lower than sera, but showed a similar antibody response pattern post infection. Thus, oral fluid samples can be used for antibody detection in lieu of traditional serology. Viral shedding in feces continued for nearly 30 days after clinical PEDV symptoms ceased in both challenged and field-infected pigs. This is important for producers who move clinically normal animals among herds that have previously tested positive for PEDV. PED viral nucleic acid continued to be detected long after fecal shedding was no longer detectable, suggesting the PEDV source in oral fluid would be external (i.e., feces or environment). Since ‘time to normal’ ranges 10 to 16 weeks after initial PED outbreak, oral fluid sampling for surveillance is useful in populations.

Principal Researcher: Dr. Kyoung-Jin Yoon, DVM, Iowa State University

Key Points:

• Oral fluid sampling accurately detects the presence and circulation of Porcine Epidemic Diarrhea Virus (PEDV).
• PEDV shedding in feces continues for nearly 30 days after clinical symptoms cease, highlighting the need to mitigate environmental contamination.
• Because oral fluid sampling picks up external PEDV exposure, it’s useful in population surveillance.

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