Iowa Farmer Today
03/04/06
New hog disease looming: Vet
By Jeff DeYoung, Iowa Farmer Today
CARROLL -- A potentially new strain of postweaning multisystemic wasting
syndrome (PMWS) could be heading to the United States.
Jim McKean, ISU Extension veterinarian and assistant director of the Iowa
Pork Industry Center, told producers here Feb. 24 European PWMS has been
found in the eastern provinces of Canada.
“Cases are increasing in Ontario and Quebec, and the question is, will it spread
into the western provinces,” he said. “We get 3.5 million pigs from the western
provinces, so if it makes it there, it’s virtually impossible to stop it from walking on
down here.”
PMWS primarily affects pigs four to six weeks after they move into the
grow/finish phase, McKean said during the Iowa Pork Regional Conference.
“Typically, you will see it in 10- to 16-week-old pigs here in the U.S.,” he said.
The disease is associated with porcine circovirus type 2 (PCV2), McKean said.
Fatality rates in groups of pigs can be high, he added.
“All the major hog producing countries in Europe have this, and the losses are
substantial. It tends to last for a long time,” McKean said.
Clinical signs include chronic wasting, pale skin color and enlarged nymph
nodes.
Normal sanitary practices on a hog operation do not appear to be sufficient to
stop it, he noted. Complete isolation, McKean said, has proved to be somewhat
effective.
Infected animals from other sow herds could spread the disease, he said. It also
could be spread throughout an area, and some believe the virus could be spread
through semen.
Because PMWS is a wasting disease, McKean said the public could connect it to
BSE (mad-cow disease). He said there is no evidence PMWS can be passed
along to humans.
However, there are other issues to be concerned about.
“You are going to need an animal-disposal strategy because you could have high
and sustained mortality problems,” McKean said. “The emotional and financial
toll is also substantial to any operation.”
PCV2 also can also open the door for other viral diseases by making the animal
more susceptible to infection, he added.
Among those are porcine dermatitis and nephropathy syndrome (PDNS), a
disease that manifests itself primarily through skin and kidney lesions.
McKean said occurrences of PDNS may be increasing in the field, adding it could
be associated with PMWS. It also can mimic classic swine fever.
PCV2 also can be linked to enteritis and reproductive failure, he said.
In occurrences of reproductive failure, McKean said it is most common with new
herds or in gilt litters. The most common result is an increase in mummified
fetuses.
Reproductive issues could come from mixing PCV2 negative and positive
sources, he added.
Once a diagnosis is confirmed, McKean advised producers to follow several
steps to control PCV2-associated diseases, including:
=Aggressive treatment of bacterial co-infections;
=determine if associated with the use of certain vaccines or the timing of a
vaccination (veterinary evaluation is required). Anti-inflammatory drugs may be
beneficial.
=pull sick pigs from the building;
=focus on decreasing stress and improving pig comfort emphasizing appropriate
pig density and flow, minimal mixing and regrouping, improved air quality and
appropriate temperature, and solid pen dividers; and
=use effective disinfectants, such as Virkon-S, between groups. McKean said
some PCV2 vaccines are on the horizon, adding researchers in Europe have had
some success. Producers should be aware of any potential new diseases and to
prepare for them, he said.
“The key to controlling something like this is to know your enemy.”