With four confirmed and six probable human cases of a new swine influenza in Pennsylvania, state Department of Health officials are watching to see whether the strain begins spreading person to person, as happened during the 2009 H1N1 swine-flu pandemic.
Four youth participants at the Huntingdon County Fair Aug. 5-11 became ill with H3N2v -- the "v" indicating a "variant" swine-flu strain that can infect people.
None of the cases required hospitalization, but all four were exposed to pigs at the fair. While the strain typically is associated with swine, the state departments of Health and Agriculture said that handling or eating pork products presents no risk of exposure to the flu.
Stephen Ostroff, director of the Health Department's bureau of epidemiology and the acting state physician general, said the strain already has infected 270 people in the United States, with 138 confirmed cases in Indiana and 72 in Ohio. For now, the direction of infection has only been pig to human.
The strain was first identified last summer in Indiana, but three cases also were confirmed in 2011 among participants of the Washington County Agricultural Fair who had exposure to pigs. This year's fair ends today. Dave Cowden, fair board president, said the board worked with the health department on last year's infections but he's heard no mention of it this year.
Dr. Ostroff said the H3N2v strain "could be an issue at any fair in Pennsylvania where animals are exhibited" and "that's why it's important to get the message out."
He recommends that people wash hands after exposure to livestock and refrain from drinking or eating while in the presence of pigs and livestock. H3N2v symptoms so far have proven to be less severe than H1N1, Dr. Ostroff said, but can include fever, coughing, fatigue and lack of appetite. Other influenza symptoms may include a runny nose, sore throat, muscle aches, eye irritation, nausea, vomiting and diarrhea.
Health officials continue watching for evidence of the flu strain passing from person to person.
"All investigations to date have documented cases in individuals who had close contact with live pigs and were either exhibitors or attended fairs," Dr. Ostroff said, noting a few cases in which people were infected from pigs on a farm. The Health Department is investigating whether people who contracted the H3N2v strain pass the flu on to friends and family members who've had no exposure to the animals.
Typically swine flu circulates only among pigs while human flu viruses remain with humans. On occasion, Dr. Ostroff said, a variant strain can jump between the two species. Strains that jump from pigs to humans raise particular concern because swine-flu infections in humans historically have caused more severe illness than seasonal flu strains, as happened with H1N1.
Dr. Ostroff said H1N1 took hold in rural Mexico in 2009 and initially, as with the current strain, involved infections in one direction, from pigs to humans. But it began spreading person to person once it reached urban areas of Mexico.
The U.S. Centers for Disease Control and Prevention estimated about 61 million U.S. infections of H1N1 from April 2009 to April 2010 with more than a quarter-million hospitalizations and a domestic death toll as high as 18,300.
Children under 5 years old, people 65 and older, pregnant women and those with chronic conditions or weakened immune systems face a higher risk from H3N2v and should use added caution and consider avoiding areas where live pigs live or are displayed.
Flu viruses are spread mainly through the air from coughs and sneezes.
Those who develop a flu-like illness who had been in contact with live animals including pigs at agricultural fairs or on farms in the week before they got sick should contact their healthcare providers, their local health department, or the state Health Department at 1-877-PA-HEALTH for advice and appropriate follow-up.state
David Templeton: firstname.lastname@example.org or 412-263-1578.