"We are excited to announce that after a long and rigorous process, Pipestone's 'PEDv in Feed Proof of Concept' paper has officially been released and is the first research study in the world that proves that animal feed can carry PEDv," said Scott Dee of Pipestone Veterinary Services in Pipestone, Minnesota and colleagues there and South Dakota State University.

They added: "We are honoured to be providing this cutting edge research to our clients and are dedicated to using this information to better the swine industry, the service we provide to our clients, and ultimately your swine herds health."

In their paper, published in BMC Veterinary Research, they report that, since its initial detection in May 2013, the PED virus (PEDV) has spread rapidly throughout the US swine industry.

Initially, contaminated feed was proposed as a risk factor for PEDV; however, data were not available to support this theory.

In their paper, they say they provide proof of concept of this risk by describing a novel means for recovering PEDV-contaminated complete feed material from commercial swine sites and conducting an in-vivo experiment to prove its infectivity.

For on-farm detection of PEDV RNA in feed, Dee and co-authors explain that paint rollers were used to collect material from at-risk feed bins from three clinically affected breeding herds. This material was tested by PCR and determined to be positive for PEDV-RNA (Ct=19.50 to 22.20 range). To test infectivity, this material was pooled (Ct=20.65) and a Treatment group of three-week old PEDV-naïve piglets were allowed to consume it via natural feeding behaviour.

For the purpose of a positive control, piglets were allowed to ingest feed spiked with stock PEDV (Ct=18.23) while the negative control group received PEDV-free feed.

Clinical signs of PEDV infection – vomiting and diarrhoea – and viral shedding were observed in both the Positive control and treatment group post-consumption with virus and microscopic lesions detected in intestinal samples.

No evidence of infection was observed in the negative controls.

These data provide proof of concept that contaminated complete feed can serve as a vehicle for PEDV infection of naïve pigs using natural feeding behaviour, concluded Dee and co-authors.

Reference

Dee S., T. Clement, A. Schelkopf, J. Nerem, D. Knudsen, J. Christopher-Hennings and E. Nelson. 2014. An evaluation of contaminated complete feed as a vehicle for porcine epidemic diarrhea virus infection of naïve pigs following consumption via natural feeding behavior: proof of concept. BMC Veterinary Research 2014, 10:176 doi:10.1186/s12917-014-0176-9.