Canadian passive vaccine could be used to treat PED

In development | Manitoba company delivers antibodies via egg yolks

A passive vaccine that could treat the porcine epidemic diarrhea virus is six to eight weeks away from presentation for federal government review.


Zyme Fast Inc., a Manitoba biotechnology company, is developing a feed additive derived from egg yolks. 


Chickens are immunized with the PED virus and produce antibodies in their eggs. The virus does not harm the chickens, and yolks of their eggs are then processed into pig feed. 


“The chicken will produce for months and months eggs with the right antibodies in it, and then you just dry the egg and feed it as a feed additive,” said Zyme Fast president Terence Sellen.


“It makes it cheaper for the farmer and it’s very effective.”


Sellen said the antibody-containing additive could act as a preventive measure as well as a cure.


PED virus has killed millions of piglets in the United States, where it is now considered endemic. Canada has confirmed 31 infected barns, 28 of them in Ontario. 


The last four were confirmed last week in four counties.


Sellen said pigs’ acquisition of immunity through feed would be quicker than injecting a traditional vaccine, which encourages production of antibodies in a response that can take days or weeks,.


PED affects the lining of piglets’ small intestines, preventing them from deriving nourishment from milk. They can die within days from dehydration and starvation.


“In this sort of form, it’s kind of a passive immunity, in that you’re not expecting the pigs to actually produce their own antibodies but you provide them antibodies that they could ingest and hopefully fight off the virus in that process,” said Mark Fynn, an animal care specialist with the Manitoba Pork Council.


“It’s not a traditional vaccine in the sense that you’re not injecting an antigen into the pigs and expecting them to mount an immune response.”


Sellen said the product could prevent piglets from getting the virus because they would ingest the antibodies needed to fight PED once exposed. 


“You don’t know where this thing is going to come so why wait until the animal is sick and it has an impact,” he said.


Fynn said the best approach is to prevent viral transmission using stringent biosecurity. Should PED find its way into a herd, the product proposed by Zyme Fast could limit losses.


“It’s more used as a treatment,” Fynn said. “You could use it preventively for it to fight the virus, but the pigs are still ingesting the virus in some form or another for this product to even work, so it’s more about trying to save the lives of piglets and also help other pigs to stay relatively healthy and get back on track and be able to produce their own level of immunity.”


Zyme Fast has been working on the passive vaccine since January. 


Sellen said it developed a PED vaccine about four years ago and licensed it to Asian producers. PED has existed in Asia since the early 1980s.


The vaccine was for a different strain of PED, but the company is using the same approach to develop a product for the North American strain.


“(The viruses) are about 90 percent the same, but 90 percent the same is not really good enough. You have to try and get much higher. We’re trying to get higher than 99 percent,” Sellen said.


PED has cost the American hog industry more than $1 billion in piglet losses, and an effective vaccine could prove lucrative for the Manitoba firm.


Manitoba has had only one case of PED since the virus first came to Canada in January, and it has been contained. Fynn said the exact source of infection has not been determined.


However, investigation has ruled out feed as the source, and the supplier of pigs to the infected wean to finish barn has also tested clean of PED.


“I’m quite pleased at the level of co-operation we got from the producer that was unfortunate enough to get the disease on his site, but also with the amount of engagement that we have from all the other pig farmers in the province and how seriously they are taking it,” Fynn said.

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