Hundreds of thousands of visitors will wander through the animal barns at the Minnesota State Fair over the next 12 days to view some of the state's top farm animals.
Whenever people and animals are in close proximity there's always a chance that a disease can pass between them.
A strain of swine influenza swept through fairs last summer sickening 309 people in a dozen states, including Minnesota. One person died from the new virus. This year 16 people have contracted influenza from pigs after visiting fairs in Indiana, Illinois and Ohio. So far, Minnesota hasn't had any cases.
The possibility that the swine virus could reappear in Minnesota has state health officials paying close attention to pigs and the people who show them. To lessen the chance that fair visitors will contract flu from pigs, the state Board of Animal Health is encouraging fairs to ban the practice of holding over some pigs after their competition has ended.
At the Steele County Free Fair in Owatonna last week, Dr. James Gute walked slowly through the swine barns, clipboard in hand.
"My main thing is to make sure there isn't anything here that's sick," said Gute, the fair's official veterinarian. "If I hear a cough, I'm going to go over and look at the pig. And if he looks a little dull to me I'm going to take his temperature. If he has a temperature, out the door they go immediately."
Fair veterinarians look for signs of many different illnesses in pigs, but Gute said the new flu strain, known as H3N2v, is at the top of the list these days.
If I hear a cough, I'm going to go over and look at the pig. And if he looks a little dull to me I'm going to take his temperature. If he has a temperature, out the door they go.
"When we get it transferring from one animal to people or from people to animals, that's when we start to get trouble," he said.
Although not a common occurrence, when flu jumps between species it is always alarming. Because people typically don't have much immunity against a new strain of flu -- illnesses can be worse. And, in the early phase of an outbreak, the most effective method of preventing flu usually isn't available.
"With the swine influenza viruses there is no possibility of protection with a vaccine right at this point," State Public Health Veterinarian Joni Scheftel said.
In most cases, H3N2v, hasn't been a severe flu in humans, Scheftel said. There is also no evidence that the virus is easily transmitted from person-to-person. If it did spread easily that would increase the potential for a pandemic.
But Scheftel said it's important to keep monitoring the situation because flu viruses are always changing.
"We do know that influenza can mutate and can become adapted to people, so that it's transmitted from person-to-person," she said. "And we like to get a handle on that as soon as possible, if it does happen."
Most of the swine at the Minnesota State Fair this year will go home after 72 hours, said Beth Thompson, senior veterinarian for the Board of Animal Health.
"If you have a sick pig coming in, it's like a bunch of kindergarteners," she said. "The more time they spend together, the more that bug is going to pass amongst them."
Signs will be posted outside of animal buildings asking fairgoers to keep food, drinks, pacifiers, baby bottles and strollers out of the barns. People who have had a fever in the past seven days are asked to stay away.
Last year, signs at the fair advised people in high risk groups to stay out of the animal barns, including children under five, pregnant women, the elderly and people with chronic conditions and weakened immune systems. But those signs are gone this year.
Scheftel, of the Health Department, said it appears that the risk of contracting H3N2v from swine is very small, and officials are ever aware that the State Fair is an important part of Minnesota's culture.
"We don't want to sort of throw out the baby with the bathwater, right? We want people to enjoy the fair in a healthy way," she said.
Fairgoers may also notice signs encouraging them to wash their hands frequently as they move through the barns. While that practice helps reduce exposure to flu viruses, Scheftel said, it is not 100 percent effective because flu spreads primarily through the air.