Not Yet….

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)

But first a message from our sponsor

Texas Human Swine Influenza Case

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

Travis CountyDSHS Central Office

Hale County

Pig Purchased

10/11/08

Bell County Case and S&W

Kendall County 2 pigs bought 10/12/08

You are here

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

Pandemic Influenza: When the Swine Flu Hits

the Fan?

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

Recorded Influenza Pandemics

USS Pandemic Flu

First Case of Human Infection with SIV, San Diego, California

March 30: •10 year old male developed fever, cough, vomiting

•Seen in urgent care clinic

•NP swab collected

• April 13, 2009, CDC notified of 10 year old boy with respiratory illness from California

Unsubtypeable influenza A virus identified from specimen at clinic

April 14: Specimen received by CDC and swine influenza A (H1N1) virus identified

Public health laboratory testing for human influenza A subtypes was negative

First Case of Human Infection with SIV, Imperial County,

California

March 28: • 9 year old female developed cough and fever

• Seen at clinic

•NP swab collected

• •April 17, 2009, CDC received unsubtypeable influenza A virus specimen from Naval Health Research Center (NHRC), San Diego

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

0

1

2

3

4

3/26

/200

9

3/29

/200

9

4/1/

2009

4/4/

2009

4/7/

2009

4/10

/200

9

4/13

/200

9

4/16

/200

9

Date

Texas Cases

California Cases

Num

ber

of C

onfir

med

Cas

es

Case Patient A Flew to Dallas,

Texas

No known epidemiologic link between the Texas and California cases

Analysis of TexasConfirmed 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*

Demographic N %Sex 846

– Male 412 49%– Female 434 51%

Age (median 10 yrs,

range 1 mos – 84 yrs)863

– <5 years 136 16%– 5-18 years 557 65%– 19-45 years 132 15%– >45 years 38 4%

*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

N Symptomatic

%

Fever (>100ºF)

(median temp: 102.0ºF)248 230 93%

Sore throat 283 169 60%Cough 313 272 87%GI symptoms (diarrhea and/or vomiting)

206 96 47%

Met Influenza Like Illness (ILI) case definition (fever and sore throat or cough)

216 187 87%

*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