Rapid Mutation Makes PRRS Control Difficult
US - The path to eliminating PRRS (porcine respiratory and reproductive syndrome) could be likened to a climb to a base camp at Mt. Everest — progress is being made, but there is still a very tall mountain to climb.“We are making progress, but PRRS is not an easy thing to deal with,“ says Lisa Becton, a veterinarian and director of swine health information and research with the National Pork Board in Des Moines.
PRRS has the ability to mutate quickly, making it even more difficult for researchers, she says. Millions of dollars have been pumped into research programmes throughout the United States, Dr Becton adds.
One method that seems to be seeing some success is an attempt to deal with it regionally, says Iowa Farmer Today.
“They are looking at it regionally in Minnesota, trying to see if they can eliminate it in a certain area,“ Dr Becton says.
“There are also some things being done in Illinois and Indiana, and we have seen some success with these efforts. This may be a method that we might be able to use to at least control it and perhaps even eliminate it totally in specific regions.“
Additional research is focusing on what makes PRRS so evasive to vaccines.
“We are looking at what causes the virulence mechanism, what is going to be most effective in vaccines,“ Dr Becton says.
“How does PRRS evade the immune system? There is a lot of research looking at the genetic and molecular makeup of PRRS, and that type of things takes a long time.“
She says one procedure that appears to be promising is filtration systems on hog buildings.
“Basically, these are put up on buildings where any air comes in, such as a curtain or ventilation system,“ Dr Becton says.
“But, it also comes at a price, and right now it’s pretty tough economically for producers. But, this does look like it will be effective.“
She says producers continue to use better biosecurity methods to help keep the virus off their farms. Basic management should greatly reduce the risk of PRRS infecting an operation, Dr Becton adds.
“Breeding stock needs to be tested before coming on the farm, and that includes bringing in semen,“ she says.
“You need to clean and disinfect all equipment. You need to reduce the amount of traffic onto your farm.
“Make sure trailers are thoroughly cleaned and dried. All of those can greatly reduce the transmission of PRRS.“
With the emergence of the H1N1 virus, Dr Becton says more attention may be paid to that virus than PRRS.
“We have been dealing with influenza in the swine industry for a long time.
“What I would like to see us do is to focus on creating an infrastructure to collect and analyse data and be able to plug this disease into a surveillance system.“
She says researchers also are looking at the effect PRRS has when it attaches to other issues, such as influenza or, most recently, circovirus.
“There is some research looking at co-infections,“ Dr Becton says.
“We saw what happened with circovirus. PRRS can also have an effect when combined with mycoplasma. So, there are issues to look at there as well.“
As the pork board and other groups continue to focus on eliminating PRRS, Dr Becton believes the money and time spent will eventually pay off.
However, she says producers need to have patience.
“We are going to have to create a diagnostic method of detecting PRRS, and that is going to take time.
“I believe we are making very good progress, and a lot of people are working on this. We get closer each year.“
Further Reading
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