There is some optimism in Canada that outbreaks of Porcine Epidemic Diarrhoea (PED) may soon be brought under control, following the identification of a feed ingredient that carries the PED virus, writes Jackie Linden. New research from the US, however, shows that the virus remains viable for a prolonged period in feed, manure and water - and it only takes a low dose of virus to infect a piglet. One can only hope Canadian optimism is not misplaced. In the last week, there have been the first reported outbreaks of African Swine Fever in Poland and Food and Mouth Disease in North Korea.
Evidence is mounting that one of the routes for transmission of the Porcine Epidemic Diarrhoea (PED) virus is through feed.
The Canadian Food Inspection Agency (CFIA) has reported a positive bioassay resulting from exposure to samples of US-origin plasma product.
Testing has determined that PED virus (PEDv) was present in samples of US-origin plasma obtained at a manufacturer for one company. This plasma was used as an ingredient in feed pellets produced by the company. Testing with a bioassay has determined that the plasma ingredient contains PED virus capable of causing disease in pigs.
This news led the Ontario Swine Health Advisory Board to announce that the main source of PEDv in eastern Canada has been stopped.
Chair of the Board said that there is a direct link to that product and those cases present a pretty clear picture of how the majority of this occurred.
From there, he says, the primary focus is on containment so as spring and early summer approach and the virus will less easily transmitted, the number of positive cases and positive sites should fall, combined with continued surveillance to aid effective early detection.
PED has been confirmed on 20 farms in eastern Canada; confirmed cases are in Ontario with suspected cases in Manitoba and Prince Edward Island.
New research at the University of Minnesota reveals that pig manure and water may also be a source of PED infection.
Sagar Goyal, DVM, looked at the ability of the PEDv to survive in various environmental settings and commented: “The very low infective dose of PED virus surprised me the most. We proved the infectious dose of PEDv to cause disease in pigs is very low - even 108 dilution of the virus infected piglets.”
Dr Goyal looked at PEDv survival in fresh manure, slurry, drinking and recycled water and ground feed. Overall, he found results similar to those for the Transmissible Gastroenteritis (TGE) virus — a related coronavirus.
The PED virus seemed from his work to survive at least seven days and it was still viable at the end of the study after 28 days in slurry at low temperatures and in wet feed. PEDv survived one or two weeks in fresh manure, drinking water and dry feed.
The total number of US pig farms testing positive for PEDv stood at 3,528 at the latest count. The first virus-positive environmental samples have been reported in Idaho and Montana, bringing the total number of states affected to 25.
Turning to notifiable swine diseases, Foot-and-Mouth Disease (FMD) has been reported in North Korean pigs. Signs were first noted in early January in a slaughterhouse in the capital, Pyongyang. It has since been found in 17 farms in several districts; 369 pigs died and 2,911 pigs have been destroyed. This is the first FMD outbreak in North Korea for three years.
And finally, turning to news of African Swine Fever, wild boar in three regions of Russia have been reported in the last week to have tested positive for the virus, as has one wild boar in Poland - the second EU country to report the disease.
The Polish case may have significance for the international pork market as Poland is the fourth largest producer of pig meat in the EU and a major trader in both pork and live pigs. The outbreak was in a region with few domestic pigs but both South Korea and Belarus have already banned imports of pigs and pig meat from Poland.
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