What do you know about influenza?
Diverging opinions from producers to veterinarians on influenza exist. Jeremy Pittman challenges the pork industry to have a better understanding of influenza.
March 9, 2018
For Smithfield veterinarian Jeremy Pittman, influenza is one of the “Big Four” of swine diseases, falling in the same category as porcine reproductive and respiratory syndrome, porcine circovirus type 2 and Mycoplasma hyopneumonaie.
Speaking at the All-Star Interactive Symposium hosted by Boehringer Ingelheim he says, “Influenza is significantly costly for hog producers. It is estimated from $3 to $10 a pig. Based on experience, I believe that is underestimating what the true cost of influenza within the production system, set of farms or flow because what you are not considering all the time and energy that goes into controlling the disease.”
For Pittman, influenza is more frustrating than PRRS. Comparing the diseases, the information and research on influenza have only been available within 10 years. Also, it’s constantly changing nature similar to PRRS but more complex. “It is a complex disease, and we work in complex systems. When you put those two things together, it is very difficult to deal with on a day-to-day basis,” he notes.
Diverging opinions from producers to veterinarians on influenza exist. He says, “There is a general misunderstanding of influenza and unfortunately oversimplification of flu as it exists today in swine production. That is at the producers, management and veterinarian level.”
It is a complex disease. New information on the disease and epidemiology is being learned every day. “One revolution that I had a couple of years ago is Influenza is a pig flow problem as it is a lateral and horizontal introduction into a growing pig population,” Pittman says.
From sow down
The sow herd is an essential component to controlling the disease. Pittman says we need to look at influenza the same way that we look at PPRS and that starts with the sow.
Historically, influenza was a seasonal nuisance. H1N1 hit a herd in the winter. The pigs got sick for a couple of days. It was high morbidity, but low mortality. It lasted about five to seven days, and pig farmers did not have to worry about it again until the next winter.
However, in 1998 with the emergence of H3N2 the whole story changes. “It is where we are today. We have multiple isolates circulating in the field. It is year round with seasonal influence,” explains Pittman.
Influenza builds gradually in the barn with a slow spread from pig to pig. It can be almost under the radar in many pig flows if pig caretakers are not looking for it. Pittman says, today you can have influenza in barns up to 60 days.
“Morbidity can be variable to low in these cases where you may not see influenza clinically significantly, but the resulting component of that is you get variable to high mortality usually not as a single entity,” he states. “We have to give credit to PRRS and other bacteria pneumonia because we do not live in a single disease world.”
Influenza is an RNA disease and can mutate. Different strains, isolates and pathogens coupled with the human seasonal N3s that come in and out of populations along with avian population in dense swine areas make it a challenging disease for pig farmers.
Previously, tissue testing sick pig leads to the discovery of influenza on the farm. “The problem with that is you only know you have a problem when you have a problem,” notes Pittman.
Hog farmers need an active routine monitoring system to understand what’s there and where it is. It can start with the gilt pool or the wean pigs leaving the sow farm. It also must be done in growing pigs.
Farms need to decide what is out there on all levels.
• Farm level or pig flow level to understand the transmission of flow with wean pigs coming off the sow farms and moved to grow-finishing units
• System levels with multiple systems layered on top of each other
• Regional level
• National level
Monitoring for influenza starts with admitting you have a flu problem. Monitoring does cost, so you can quantify that the problem is big enough to justify the cost of monitoring.
Once a farm decides to monitor, it needs to answer the following questions before beginning the process.