DES MOINES, Iowa – Gilles Routhier was working busily at the World Pork Expo, extolling the virtues of the air filtration systems his Quebec-based company sells to minimize disease outbreaks in hog barns.
A few dozen metres away, a leading U.S. swine veterinarian had just revealed studies that showed air filtration is the most important means of controlling the spread of new strains of Porcine Reproductive and Respiratory Syndrome, or PRRS.
Research from the Swine Disease Eradication Centre at the University of Minnesota shows that PRRS can be eradicated within 20 years, and its spread can be drastically reduced in infected areas, said Scott Dee.
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It can be controlled by the use of air filters, vaccines, biosecurity and intensive surveying of health status and then eliminated once spreading has ended.
“People didn’t think they could get rid of PRRS. They would clean it out but then get reinfected. Now we’ve got the ability, I think, to keep it out of their farms,” said Dee.
In a surprise to most of the hog industry, aerosol infection appears to be the main disease transmission method and air filters the key to eliminating infection.
Recent tougher strains have been measured by his researchers and still viable after blowing 4.7 kilometres from their barn of origin.
“In swine dense regions, I think air transmission is number one,” said Dee.
New barns should have air filters built into the structures. Older barns can have air filtration systems retrofitted for a cost of about $1 to $2 per pig if spread over a 10-year period.
With PRRS estimated to cost producers about $5 per pig, that would add up to major savings, Dee said.
Systems work best if they are installed in the barn’s attic, because ground level systems get banged by people and equipment and are exposed to rodents and other animals.
Dee said air filters can also keep out aerosol infections of H1N1 and mycoplasma.
“It should have the same effect for all three. One size fits all,” he said.
All the other methods of biosecurity are still essential.
“You can’t forget about the trucks and the people and the pigs and the semen, but I think with the whole package, we can actually make some progress in the swine dense regions.”
Repeated vaccination of pigs is also effective, Dee said. Vaccinated pigs appear to shed far less of the disease and new strains have trouble breaking in.
Dee said newly developed monitoring software and systems now allow veterinarians to analyze local situations, which allows for an area-wide approach for eradication.
The most important parts of the pork production chain to control PRRS are the early breeding steps, because infections from there spread widely.
But if PRRS-free pigs can come out of the breeding herds and don’t arrive with breeding sows and boars, infections can be cleaned up easily.
Dee said there’s finally light at the end of the tunnel for producers struggling with PRRS, and they should be excited that a curse they thought was eternal can likely be lifted within 20 years.
“I’m optimistic because there are so many of us working together.”
