Farm News, IA
01-31-07
Circovirus takes hold in Iowa
By Kristin Danley-Greiner, Farm News staff
DES MOINES — Pork producers learned at the Iowa Pork Congress last week
that a common swine disease plaguing Canada since the 1990s has reared its
head in Iowa herds.
Porcine circovirus associated disease (PCVAD) encompasses a number of
disorders, including PCV2—a newly “recognizedî” virus. It is formerly known as
postweaning multi-systemic wasting syndrome or PMWS. Dr. George
Charbonneau with Swine Services Group out of Canada spoke at the Congress
about using PCV2 vaccines to control PCVAD. As a veterinarian in private
practice, Charbonneau has worked with clients to minimize the damage of
PCVAD, and also serves as a committee member with the Ontario Pork Industry
Council’s swine health advisory board.
“Beginning in the late fall of 2004, there has been a significant increase in the
number of herds affected and the severity of PCVAD in eastern Canada,Ӕ
Charbonneau told Farm News. “Although some believe that the increase in
PCVAD is due to an as yet unidentified agent ‘X’ that is either causing the
disease outright or setting off PCVAD as a ‘triggering agent,’ the more common
theory is that the increased spread of PCV2 virus that more closely related to the
problematic European strains is responsible for the more widespread and severe
disease.î”
Iowa State University has documented several hundred cases of the virus
dating back to the late 1990s. Dr. Hans Rotto, a private practitioner, also does
production consulting for all sizes of swine operations across the U.S. with his
Ames-based business, Innovative Agricultural Solutions. Rotto, who also spoke
at the Congress, said this disease has become more important and problematic
in herds throughout Iowa in the last 18 months.î
“It has been a problem in all sizes of herds and types of operations. However,
this does not mean everyone is having a problem in Iowa,Ӕ he said.
The virus is spread horizontally from pig to pig via manure and body fluids. Pigs
are most commonly affected at approximately four to five weeks after being
placed in a finisher. Some producers have reported mortality rates surpassing 35
percent and morbidity rates exceeding 50 percent in some barns. PCV2 has
been detected in semen in both experimental and field cases.
Charbonneau pointed out that the signs of the various PCVAD-associated
diseases range from difficulty breathing, enlarged lymph nodes and jaundice to
red blotchy skin lesions, fever, cough and stillbirths in sows.
Veterinarians say the first step in combating PCVAD is to accurately identify it,
then confirm it with a clinical diagnosis. A veterinarian’s diagnosis is critical,
because pigs experiencing PCVAD can have clinical signs that can be mistaken
for many other diseases, especially because co-infections are common.
Producers should manage the triggers and various factors that lead to PCVAD by
treating the secondary opportunistic pathogensî in the herd, Rotto said.
Biosecurity plays an important role in this, experts say. Preventing the range of
diseases include ensuring that stress levels are low, such as providing enough
room for piglets to access feeders and to allow for adequate water supplies. The
air flow in a building should be up to par, with ammonia levels at less than 10
parts per million to help reduce toxic gasses. Pigs at various levels of production
should not mix by maintaining pig groups established at weaning through
finishing.
Pens should be properly cleaned and disinfectants used to help prevent the
occurrence of other diseases that could lead to a PCVAD outbreak. Aerial
disinfecting with pigs in the facility also helps reduce the spread of the virus,
some say.
Antibiotics don’t touch PCVAD, but Fort Dodge Animal Health (FDAH) last year
received full licensure from the U.S. Department of Agriculture for the first
vaccine for PCVAD it developed in conjunction with Virginia Tech and Iowa
State.
Suvaxyn PCV2 One Dose is labeled as an inactivated, one-dose vaccine for
piglets four weeks of age and older to aid in the prevention of PCV2 and control
of lymphoid depletion (infection of the lymph nodes) caused by PCV2.
For more information about PCVAD, go to www.pork.org/
PorkScience/Documents/PCVADBrochure.pdf.