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H3N2 variant influenza A Maine, 2011

H3N2 variant influenza A Maine, 2011. Sara Robinson, MPH Epidemiologist Maine Center for Disease Control and Prevention. H3N2 in Swine and Humans. H3N2 began circulating in swine in the U.S. in 1998, introduced by humans

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H3N2 variant influenza A Maine, 2011

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  1. H3N2 variant influenza AMaine, 2011 Sara Robinson, MPH Epidemiologist Maine Center for Disease Control and Prevention

  2. H3N2 in Swine and Humans • H3N2 began circulating in swine in the U.S. in 1998, introduced by humans • Currently circulating swine flu H3N2 viruses are different from human H3N2s. • Sporadic human infections with SI do occur usually in people exposed to swine at fairs or farm workers. • Limited human-to-human spread.

  3. Variantinfluenza A (H3N2v) • This particular virus carries the M gene from the 2009 H1N1 virus. • This virus first reported in a human from Indiana in July 2011. • 12 total cases reported in 2011 • 2 in Indiana -3 in Iowa • 3 in Pennsylvania -2 in West Virginia • 2 in Maine • 1 case reported to date in 2012, in Utah

  4. Case A – lab information • 10/14/2011 – Maine’s Health and Environmental Testing Laboratory (HETL) notified Maine CDC of an influenza A positive sample • Positive for H3, and the swine component of H1N1 • Sample collected as part of an enhanced surveillance initiative in Maine • Sample forwarded to federal CDC for confirmation – confirmed as swine-origin triple reassortant influenza A(H3N2) on Monday 10/17/2011

  5. Case A – Epi info • 7 yo M with symptom onset of fever, cough, headache, sore throat and myalgia on 10/07/2011 • Seen at providers office 10/10/2011 • Rapid influenza A positive • Sample taken for PCR testing (enhanced surveillance) • Underlying conditions: asthma • No 2011-2012 season influenza vaccine (vaccinated in 2010) • Treated with Tamiflu • Case A visited agricultural fair multiple days and spent time in the swine barn • No known direct contact with pigs

  6. Agricultural Fair • New swine barn at the fair with over 150 swine exhibited. • 160,000 + attend this fair and many visit the swine exhibit (probably the only time that many people SEE a pig). • Ten swine exhibitors at the fair from NH, MA and ME. • Four pig scrambles held throughout the fair week, 10 baby pigs per scramble, 10-14 2nd- 3rd graders in each event.

  7. Agricultural and Epi Response • Investigation revealed there were some sick pigs at the fair and one of the scramble pigs died. • All farms were visited and all pigs examined by a regulatory veterinarian. • USDA guidelines only recommend testing swine with influenza-like illness. Samples submitted from two farms, both negative. • Numerous people with ILI identified through farm contacts, all interviewed, several tested, all negative.

  8. Epi Response • Sent health alert state wide • Notified area providers and hospitals • Encouraged PCR testing (notified area commercial labs) • Contacted case’s school to enhance surveillance • Contacted schools that participated in pig scramble to enhance surveillance • Several ill individuals identified, all tested negative for influenza

  9. Case B – lab information • 10/28/2011 –HETL notified Maine CDC of an influenza A positive sample • Positive for H3 • High CT count • Provider noted swine contact on submission form, sent for confirmation because of epi link • Sample forwarded to federal CDC for confirmation – confirmed as swine-origin triple reassortant influenza A(H3N2) on Monday 10/31/2011

  10. Case B – epi information • 8 yo M with symptom onset of fever, myalgia, and runny nose on 10/22/2011 • Seen at providers office 10/24/2011 • Sample taken for PCR testing • No 2011-2012 season influenza vaccine (vaccinated in 2010) • Case A visited agricultural fair multiple days and participated in a pig scramble, winning one of the pigs • Case helped take care of pigs at family friend’s farm

  11. Secondary Response • Contacted farm where pig was located • This farm had been visited after the 1st case was identified • 2 secondary farms bought pigs from this farm • Both were visited, ill swine swabbed • One pig was PCR positive, but unable to isolate virus – inconclusive results • Contacted family • Sibling was ill with ILI, but influenza testing was negative, viral culture also negative

  12. Timeline Case B onset Case A onset 10/22 10/7 Lab confirmation Case A Lab confirmation Case B 10/17 10/31 No additional human cases detected 10/2 Fair 10/9 11/9 10/27 Swine samples collected Swine samples collected 10/19 Health Alert (human and animal)

  13. Conclusions • Both cases had documented swine exposure • No human to human transmission identified • Plenty of sick pigs, and sick humans but difficult to get positive influenza tests • Increased awareness important • Importance of PCR testing • Importance of collaboration with the lab, and with the Department of Agriculture

  14. Acknowledgements • Maine CDC • Stephen Sears • Lauren Ball • Kate Colby • Heidi Mallis • Lori Webber • Brian Bernier • USDA • Chip Ridky • Frederic Cantor • Nicole Giguere • Bill Smith • Department of Agriculture • Don Hoenig • Beth McEvoy • New Hampshire • Stephen Crawford • John Dreisig • Massachusetts • Lorraine O’Connor • Federal CDC

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