First figures from joint diagnostic labs throughout the United States have revealed that Porcine Epidemic Diarrhoea Virus (PEDV) has been confirmed in at least 103 specific sites.
Prof Dr Greg Stevenson, Iowa State University
The diagnostic labs in of Iowa State University (ISU) and Minnesota State University have tested 113 positive for PEDV.
Until about three weeks ago the disease was thought not to exist in the United States. It affects pigs from all ages, but is predominanly causing mortality in the preweaning phase, with preweaning mortality rates of 95% reported. The disease is endemic in various East Asian countries.
Dr Greg Stevenson, professor at ISU’s Diagnostic Veterinary Lab, addressed the audience at World Pork Expo at a luncheon devoted to PEDV. He said the samples were from 11 states. Most samples were found in the most pig-dense state Iowa (62), followed by Minnesota (15), Indiana and Colorado (both 7), Ohio (4), Missouri, Illinois (2) and Michigan, Nebraska, Oklahoma and South Dakota (all 1).
The virus was confirmed at 26 sow farms (breed to weaning) and 77 ‘non-sow farms’.
The first incident to PEDV was reported on April 29, after which it took some time to confirm it was PEDV since initial thoughts went out to Transmissible Gastro-Enteritis (TGE), a disease known to produce the same clinical signs.
When backtracking some cases, the first now known appearance of the disease was in mid-April, on a farm in Ohio, on a growing pig site.
Stevenson said that after sequencing the genome of the virus was over 99% identical to the genome of PEDV found in China in 2012. Since PEDV is a virus that mutates relatively quickly, he said that it is therefore likely that the virus hasn’t been in the US for much longer.
Stevenson added that the initial data ought to be taken with some care. Since the occurrence of the disease is still fresh and since many labs initially thought TGE was the cause of the disease, exact and definite figures are hard to find as yet.
Dr Tom Burkgren, executive director of the American Association of Swine Veterinarians (AASV) told the audience that the AASV aims to figure out how the virus got into the country in order to block this road for future diseases. “Is it a biosecurity issue?,” he wondered. The AASV hopes to learn more by having a survey carried out among vets.
Dr Lisa Ferguson, deputy director for science & technology at the US Department of Agriculture – Animal & Plant Health Inspection Service (Aphis), said that the USDA is not considering making it a regulatory disease, as it does not affect public health. The only questions so far from pork importing countries were from the EU and Canada – only to curiously find out what was going on, she said.
She added also feed is being tested to figure out whether that could have been the initial source of contamination.
Dr Lisa Becton, director of swine health & research at the National Pork Board, revealed that the board had made available $450,000 for research into finding answers to PEDV.`
Dr Hank Harris of Harrisvaccines said that his company is working on a preliminary PEDV vaccine to reduce the effectiveness of the virus. He expects to have this, with a provisional licence from the USDA, available within two months.
The speakers said that PEDV is not as much affected by summer’s high temperatures as TGE is. Usually TGE does not spread well in summer – PEDV does not flourish, but does not degrade as quickly too. “It is just more stable.”