COLUMBUS, Ohio — That cute little pig on display at a local fair could be carrying a miserable flu virus.
Hog shows are common in the United States, and events are held at county, state and national venues.
Disease surveillance is showing these pigs can share influenza viruses with people. The viruses may also be mutating into novel forms that could be carried back to commercial operations.
“Everything we teach you not to do in farm biosecurity, we do at fairs,” said swine and influenza specialist Andy Bowman of the Ohio State University’s college of veterinary medicine.
“We bring these pigs together, we commingle them and then we invite the public to come.”
Probably a million pigs are shown each year in the United States.
“We know this is a small subset of the swine industry within the U.S. and they are mostly raised for youth and education programs,” Bowman said.
Show entrants vary from fewer than 300 to 2,000 pigs at one venue.
There were 306 human cases of H3N2 in 10 states during the summer of 2012. Indiana had the most, and Ohio had 107 cases with 11 hospitalizations and one death.
The majority of cases had prolonged direct or indirect exposure to swine exhibitors or family members and were linked to 14 of Ohio’s agriculture fairs, he said at the National Institute of Animal Agriculture annual meeting, which was held April 3-6 in Columbus.
A wide surveillance program has started in which pigs are sampled by wiping their noses. Influenza, PRSS and other diseases were detected.
More than 60 percent of the pigs were often infected when positive cases were diagnosed. The disease is probably amplified, and pigs may also pick up viruses from handling equipment.
Illinois, Indiana, Iowa, Michigan, Missouri and Ohio are participating in the surveillance program.
Fair organizers and state animal health officials are also involved to learn where pigs were shown and where they came from.
It is a diverse mixture of hog farms from commercial barns to a couple pigs in the backyard.
“Their management is completely different from commercial swine production and we probably need to start applying commercial swine practices,” he said.
Nine agriculture fairs in Ohio and Indiana were enrolled in the surveillance network in 2014. Pigs were sampled and uniquely identified by ear tag. Snout wipes were collected upon arrival at fairs, and the samples were sent away for PCR tests to isolate the virus.
Questionnaires that were circulated among exhibitors found that most do not have pigs year round. Many were used in youth projects and were probably bought from an off-farm source in March or April.
Other livestock such as cattle, sheep, horses and llamas are often on the farms, and there could be two to 6,500 pigs on a farm.
Some hog owners attend at least three shows before the fair where the hogs were sampled. Others show throughout the season, and some reported being at as many as 50 shows. Jackpots were considered another source of disease spread.
A working group was established in 2012 to minimize swine influenza transmission at fairs. State health officials, pork boards, the U.S. Department of Agriculture and veterinarians were involved.
They recommended shorter swine exhibitions because it appears the amount of flu cases drops at shorter events. Vaccination was also suggested, and human contact should be minimized.
The National Pork Board also requested a study into influenza and exhibitions.
The public health sector has said these events should be shut down. However, more research and evidence are needed to decide what to do with fairs and potential exposure to sickness.
“We know not all fairs have the same risk,” Bowman said.
They do know that longer fairs with large numbers of entrants are a greater risk.
“The exhibition swine sector is nervous that we are going to come after the shows and shut them down,” he said.
These shows are not typically terminal events where the pigs are sold and slaughtered afterward. Most return home and continue to spread viruses at the next fair.
“We know when people buy a barrow for $5,000 they want to show it more than once,” he said.
“There is a push-back not to have terminal shows.”