GREENSBURG, Ind. — Uncertainty about a pig’s immunity to
porcine epidemic diarrhea virus continues to rise as farms, including an
operation in Indiana, experience second outbreaks of the disease.
It was determined the Indiana farm had been re-infected at
the end of March when there were deaths of baby piglets.
The farm first had an outbreak of the virus in May 2013, had
it cleaned up by September 2013 and had not had any clinical signs of the virus
again until March 2014, said Matt Ackerman, veterinarian with Swine Veterinarian
Facts surrounding immunity from the virus still are
Originally, veterinarians hoped immunity would last two to
three years because pigs previously had a longer-lasting response to
Transmissible Gastroenteritis, a disease caused by a coronavirus similar to the
virus that causes PEDV, Ackerman said.
“No one thought there would be lifelong immunity, but we
certainly hoped there would be two to three years,” he said. “Now, instead of
farms breaking once every three years, there could be losses every six
A challenge for producers is that pigs, when born, aren’t
protected from the virus.
The second outbreak has differed from the first outbreak of
the virus, Ackerman said. The first time around, the Indiana operation lost 3.6
weeks of pigs over eight weeks then went back to regular production.
The second outbreak has came in lighter, but lasted longer,
Ackerman said. The operation is experiencing week 10 and has lost about three
works worth of pigs.
To combat the virus, producers can do three things, Ackerman
said. Producers should consider vaccination, implement biosecurity precautions
and, once the virus is identified, the area needs to be sanitized with bleach or
some other disinfectant or powder that kills the virus.
Tom Burkgren, executive director of American Association of
Swine Veterinarians, said they have not been able to track the number operations
experiencing second outbreaks.
At this point, most of the second outbreaks are anecdotal
information heard through the swine vine, Burkgren said.
The reason for the recurrence of the virus is unclear
because some farms clean up and don’t have recurrence and others clean up, get
it back to great production and, like the Indiana farm, come out with the same
strain of virus, Burkgren said.
“It’s a tough virus, and one of the problems is we don’t
know everything we need to know about immunity,” he said.
As far as combating the virus, Burkgren agreed cleaning up,
increasing biosecurity and considering feed risk factors are some answers.
This specific Indiana operation having litters be infected a
second time is concerning because it is a well-run herd with an excellent
veterinarian, Burkgren said.
“The virus has surprised us in a number of ways. It’s an
area we need more knowledge,” he said.
The upcoming summer months should help with slowing down the
Producers should take advantage of the warmer weather and
increase cleanup efforts — washing, disinfecting and drying everything that
could transmit the virus back on the farm, Burkgren said.
Although the virus still is a major challenge for producers,
it is not a human health concern. Pork remains completely safe to eat, and it
poses no risk to other animals, people or food safety.
Ackerman said he appreciated the work being done by the U.S.
Department of Agriculture, the AASV, state animal health officials, the National
Pork Producers Council and the National Pork Board.
The organizations are continuing to collaborate together to
fund research and find the answers needed to combat the virus.
“We’re doing all we can to eliminate the virus and will
continue to do so,” Ackerman said.