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Not Yet…. Novel Human Swine Flu Event Texas 2008. Neil Pascoe DSHS Matt Cochran TAHC. Program . Swine flu investigation 2008 Discuss Pandemic Influenza Novel H1N1-2009 (Swine Flu). But first a message from our sponsor. Texas Human Swine Influenza Case.
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Novel Human Swine Flu EventTexas 2008 Neil Pascoe DSHS Matt Cochran TAHC
Program • Swine flu investigation 2008 • Discuss Pandemic Influenza • Novel H1N1-2009 (Swine Flu)
First Notification 11/3/08 3:21 PM • Just a heads up. We sent specimen AVI0800070 to CDC on Thursday of last week. It was positive for FLU A but thus far, we have not been able to subtype it. CDC is running additional tests to determine if this is a "true" unsubtypeable Flu A. I expect to hear from CDC tomorrow. And FYI, this could be a reagent issue, but we should know more tomorrow. Thanks - martha • Martha Thompson, MPH • Viral Isolation Team Leader
Case • 14 YO male, Gr. 9 HS student • Hx of asthma otherwise healthy • Onset Tuesday 10/14/08 F/ST/cough sent home from school • Presented 10/15/08 local OP clinic • Fever 103F • Cough, HA, sore throat, conjunctivitis, diarrhea • flu vaccination 2008 (according to mother)
Household • Parents and 2 siblings • Brother 12 yo 7th grade • Sister 6 years, 1st grade • No one else ill • Cats, dogs, goats, pigs • Case raises show pigs and recently purchased pigs the previous weekend
Investigation • Flu study conducted in Bell County (reason for culture) • Early in flu season but no increase in ILI • School surveillance showed no increase in absenteeism • Specimen collected 10/15 sent to DSHS 10/24 (for routine subtyping) and to the CDC on 10/30 • Serum collected 11/6 from all family members sent to CDC (preliminary results are neg.)
Texas Swine Influenza Case • October 11th, 2008 visited: • Plainview, ‘Ring of Success Pig Sale’ (purchased pig) • This pig originated in Nebraska • This pig had a “light cough” when purchased and a “light rash” and was “lethargic” – new owners attributed the rash to the hay bedding and treated with benadryl, and treated the cough with Nuflor (Florfenicol) • October 12th, 2008 visited: • Comfort Texas (purchased 2 pigs) • October 14th, 2008 • Onset of clinical signs in 14 year old boy
You are here Hale County Pig Purchased 10/11/08 Kendall County 2 pigs bought 10/12/08 Travis County DSHS Central Office Bell County Case and S&W
Texas Swine Influenza Case • ‘Case pig owners’ contacted by TAHC on 11/4/2008 • Sick pig was purchased at ‘Ring of Success Pig Sale’ in Plainview Texas • Pig was not consigned to the sale, but sold under private treaty off the trailer in the parking lot outside the sale • Seller had ~60 pigs for sale • Pig was transported home on a trailer with several other pigs originating from various sources and belonging to various owners • A third party hauler
Investigation Participants • Bell County HD • Angi Bridges, • CDC • Lyn Finelli, Lenee Blanton, Steve Lindstrom, Tom Gomez et al • DSHS • Martha Thompson and lab, Neil Pascoe, Russ Jones, others • NVLS • Sabrina Swenson, Beverly Schmitt, others • TAHC • Andy Schwartz, Tommy Barton, Dee Ellis, Matt Cochran, others
Influenza A • Only flu A has subtypes • 3 main subtypes have been identified with the majority of human disease (H1, H2, H3) • Potential for tremendous genetic diversity • Only flu A causes pandemics
Human Influenza Taxonomy • A (H1N1)/New Caledonia/20/99 • Type subtype Geographic strain year of origin number isolation (often referred to as strain) Non human species will be described A(species)(H1N7)/Austin/325/2005
Hemagglutinin • Membrane protein that binds to cell surface receptors • 16 different subtypes exist (1-16) • Only H1, H2, and H3 have circulated in humans in the last century
Neuraminidase • 9 different subtypes (1-9) • Responsible for penetration of epithelial cell wall- replication • Only N1 and N2 have circulated in humans in the past century
Antigenic Drift • Only Flu A • Responsible for yearly influenza activity • Point mutations resulting after errors in RNA dependent RNA polymerase (3.6 x 10 –3 nucleotide changes/nucleotide site/year for hemagglutinin protein of influenza A as opposed to 1.6 in influenza B) • Same subtype-H3N2 (Panama, Fujian, Korea)
Antigenic Shift • Results in novel subtype (H5N1, H9N2, H7N3) • Responsible for pandemics • Facilitated by segmented genome and large reservoir of different influenza A HA and NA subtypes in wild birds
Pandemic Influenza • Global outbreak of a new subtype of influenza to which virtually no one is immune • Novel subtype (strain) • Susceptible population • Virulent • Transmissible person to person • Emergence of a novel strain can occur via: • Radical change in virus already infecting humans • Change in virus previously only seen in animals that allows it to infect humans
First Case of Human Infection with SIV, San Diego, California • April 13, 2009, CDC notified of 10 year old boy with respiratory illness from California • March 30: • 10 year old male developed fever, cough, vomiting • Seen in urgent care clinic • NP swab collected Unsubtypeable influenza A virus identified from specimen at clinic Public health laboratory testing for human influenza A subtypes was negative April 14: Specimen received by CDC and swine influenza A (H1N1) virusidentified
First Case of Human Infection with SIV, Imperial County, California • April 17, 2009, CDC received unsubtypeable influenza A virus specimen from Naval Health Research Center (NHRC), San Diego • March 28: • 9 year old female developed cough and fever • Seen at clinic • NP swab collected NHRC identified virus as unsubtypeable influenza A with possible swine origin April 17: Specimen received by CDC and identified as swine influenza A (H1N1) virus
Confirmed Cases of Human Infection with SIV No known epidemiologic link between the Texas and California cases Case Patient A Flew to Dallas, Texas Number of Confirmed Cases
Analysis of Texas Confirmed H1N1 Case Summary As of 5/27/2009 at 10:00AM The case summary is produced as analysis is complete. It may not include all cases and may not match CDC’s case numbers.
Demographics* *Based on confirmed cases for whom these data are available at time of report
Additional Data on Confirmed Cases* • Vaccinated within the last year for seasonal influenza • 34% (74 of 217) of children ≤18 years old • 26% (10 of 38) of people >18 years old • 8% (21 of 274) with recent travel to Mexico • 14 Cases were hospitalized (1 from Mexico) • 4 required ICU care • 6 deaths have been confirmed (as of 6/2/09) *Based on confirmed cases for whom these data are available at time of report
Signs and Symptoms *Based on confirmed cases for whom these data are available at time of report
Rapid Testing Data for Confirmed Cases as of 5/27/2009 10:00am • Rapid flu test results available for 218 confirmed cases • 92% (201 of 218) positive for Flu A • 4% (9 of 218) positive flu undifferentiated • 4% (8 of 218) negative