CHICAGO - A research study has shown for the first time that livestock feed can carry a virus that has killed about 13 per cent of the US hog herd, the study's lead author said, confirming suspicions among farmers and veterinarians battling outbreaks.
The findings, published this month in the peer-reviewed BMC Veterinary Research journal, bring increased scrutiny on the feed industry in the fight against Porcine Epidemic Diarrhea virus, or PEDv.
The fast-moving virus has killed an estimated 8 million piglets since it was first identified in the United States last year, pushing US pork prices to record highs.
In the study, researchers collected feed residue from three farms in Iowa and Minnesota that had outbreaks of PEDv and had received feed from the same source.
They fed it to five piglets in an experiment at South Dakota State University, and all became infected with the virus.
Piglets that were not fed the infected feed did not get sick.
"This study helped validate that the virus was alive in the feed," said Scott Dee, director of research for Pipestone Veterinary Clinic in Minnesota and lead author of the study, in an interview. "That had never been done before."
The study did not determine how the feed became infected with PEDv.
It is possible that ingredients in the feed, such as corn or soybeans, were contaminated with the virus.
The feed also could have been contaminated in other ways, such as during transportation, Dee said.
It did not contain pig blood products used in feed that are suspected by some of transmitting the disease.
Researchers have been trying to identify the ways in which PEDv is spreading to help control outbreaks.
The results of Dee's study are "one more piece of the puzzle that we've been looking for," said Tom Burkgren, executive director of the American Association of Swine Veterinarians.
The American Feed Industry Association declined to comment.
The study shows it is critical for farmers to press feed suppliers about the practices used to prevent PEDv contamination, said Paul Sundberg, vice president of science and technology for the National Pork Board.
"Quiz them and challenge them to ensure that the biosecurity in that feed handling system is sufficient in preventing PEDv in getting through to that feed," he said.
Researchers had previously established that PEDv was transmitted from pig to pig by contact with manure, which contains the virus.
It can also be spread from farm to farm on trucks.
The virus causes diarrhoea and vomiting and is nearly always lethal to baby piglets.