Variant influenza shows need for animal, human hygiene
BISMARCK, N.D. — Cases of variant influenza in humans that may have originated in swine underscore the need for keeping ill humans and animals at home, North Dakota State Veterinarian Susan Keller says.
The North Dakota Health Department believes two people — a North Dakota child and an out-of-state resident — may have contracted a strain of influenza from swine at the North Dakota State Fair.
A North Dakota child tested positive for variant influenza A H3N2v, determined through what Jill Baber, an epidemiologist at the North Dakota Department of Health, says is very specific, accurate genetic testing on the strain. After such a test is confirmed, Baber says health officials go through a long, detailed survey to try to find likely places in which the strain could have been contracted.
The child had no known contacts with people suffering from influenza, and the only contact the child had with swine was at the North Dakota State Fair in Minot. A second case, involving an out-of-state visitor to the fair, also has been confirmed with similar findings, Baber says.
Baber, who coordinates the department's influenza program, explains the Centers for Disease Control and Prevention says swine strains of influenza "have not been demonstrated to pass from human to human." Were that to happen, it would be considered a "pandemic" influenza, she says, adding that there is no indication of that.
Keller, however, explains that it's not possible to say for certain where cases originated without doing more comprehensive testing among the humans and swine in attendance at the State Fair. No pigs at the State Fair were confirmed to have the strain of influenza, she says. While several pigs were taken home during the fair due to illness, none appear to have had influenza, she explains.
Different forms of influenza are known to mutate constantly and to pass among humans, swine and birds, Keller says. That can make it difficult to know where particular cases originate.
"Influenza is anything but black and white," she says.
Baber says it's possible more people have contracted the strain but have either had no symptoms or not enough symptoms to warrant visiting a doctor. Only the state and the CDC can perform tests that show animal strains of influenza.
Variant strains of influenza that originate in swine tend to be less severe than human strains, Baber says. The people most at risk of developing severe symptoms are people with weakened immune systems. Other people may have contracted the strains but do not exhibit symptoms sufficient to go to a doctor or to get further testing.
Keller says it's important to take precautions to protect humans and animals at any time. Signs at the State Fair warn people to avoid the barns if they're ill, as they can pass their germs to livestock and vice versa. She advises "admiring animals instead of kissing them," even if that photograph of a kid up to the nose of a pig sounds adorable. Parents should keep children in strollers from touching animals, she says.
Baber adds that it's a good idea to wear gloves when working with animals.
"If you want to live in this world and you like animals, you take whatever precautions are reasonable and practical," Keller says.
She says there are no major health issues among swine or humans from the variant influenza recently discovered. Health and veterinary officials will continue to monitor the situation, but no further testing has been ordered by the Health Department or the CDC.
"I'm not worried about this one at all," Keller says.