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    Infectious Disease Prevention Section
    Mail Code: 1927
    PO BOX 149347 - Austin, TX 78714-9347
    1100 West 49th Street, Suite G401
    Austin, TX 78714

    Phone: (512) 776-7676
    Fax: (512) 776-7616




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image1 Influenza
ICD-9 487; ICD-10 J10,11
Related Topics: Protecting Yourself During the Cold and Flu Season, Avian Flu, Vaccine Preventable Diseases, Asthma and SARS

2009 - 2010 Texas Influenza Surveillance Information

The "new" flu season (2009-2010) officially began October 4, 2009. For reports from the
2008-2009 season, please see

Influenza Surveillance Report for MMWR Week 40

The influenza (flu) activity level for Texas for the week ending October 10, 2009 was “widespread.” For definitions of flu activity levels please see During week 40, 1,029 (31.8%) specimens tested by NREVSS laboratories in Texas were positive for influenza. The percentage of visits for influenza-like illness as reported by ILINet providers in Texas was above the regional baseline during week 40.

Reports from Health Service Regions

Reports were received from all Health Service Regions (HSRs) for week 40. HSRs 1, 6/5S, 8, and 9/10 reported an increased level of flu activity compared to week 39. HSRs 2/3 and 11 reported the same level of flu activity compared to week 39. HSRs 4/5N and 7 reported a decreased level of flu activity compared to week 39. For a map of Health Service Regions please visit the following website:

Laboratory Results

During week 40, fourteen hospital laboratories and public health agencies across Texas reported conducting a total of 3,239 influenza tests (antigen, culture, and PCR) to the National Respiratory and Enteric Virus Surveillance System (NREVSSwindow_ext) sponsored by the Centers for Disease Control and Prevention (CDC). The majority (69%) of influenza tests reported to NREVSS were antigen detection tests; these tests cannot identify the subtype of influenza detected. The results from Texas participants in NREVSS are summarized in the table below.
Testing Information Week 40
No. of specimens tested 3,239
No. of positive specimens (%) 1,029 (31.8%)
Positive specimens by type/subtype
Influenza A 1,025 (99.6%)
          Subtyping performed 230 (22.4%)
                A (novel H1N1) 230 (100%)
                A (H3) 0 (0%)
                A (Seasonal H1) 0 (0%)
          Subtyping not performed 795 (77.6%)
Influenza B (0.4%)

Additional influenza test results (rapid tests, culture, PCR) were reported from providers and public health departments throughout the state (see county map below).

Novel Influenza A Virus Infections

Please see the Texas Department of State Health Services (DSHS) novel influenza website ( and the CDC website ( for more information. Data collection for confirmed novel influenza A (H1N1) hospitalizations, intensive care unit (ICU) admissions, and deaths began in Texas on September 20, 2009. Forty-seven confirmed novel influenza A (H1N1) deaths were reported in Texas residents and one child from Mexico who died in HSR 6/5S prior to September 20, 2009 (these deaths are included in the cumulative data table below). The table below summarizes the current data by Health Service Region. For more data, please see

Cumulative Surveillance Case Summary for Novel Influenza A (H1N1)
by Health Service Region and County as of 10/10/2009
Health Service Region or County Hospitalizations* Intensive Care Unit (ICU) Admissions* Deaths**
Region 1 Total 6 4 2
Region 2/3 Total 146 15 11
Region 4/5N Total 34 8 3
Region 6/5S Total 86 21 12
Region 7 Total 38 6 8
Region 8 Total 59 10 14
Region 9/10 Total 19 1 8
Region 11 Total 99 27 24
Texas Total 487 92 82
*Reporting for hospitalizations and ICU admissions began on 9/20/2009. ICU admissions are included in the hospitalization totals.
**Reporting for deaths began 4/15/2009 and includes a child from Mexico.

Antigenic Characterization

Since June 9, 2009, CDC has reported antigenic characterization results from 8 novel influenza A (H1N1) viruses received from the Texas Department of State Health Services (DSHS) Laboratory since April 26, 2009.

Influenza A (H1N1) [8]

  • All 8 viruses were characterized as A/California/07/2009-like (H1N1), the reference virus selected by the World Health Organization (WHO) as the vaccine strain for the novel influenza A (H1N1) vaccine.
Influenza A (H3N2) [0]
  • No influenza A (H3N2) viruses from Texas have been characterized since April 15, 2009.
Influenza A (H1N1) seasonal [0]
  • No seasonal influenza A (H1N1) viruses from Texas have been characterized since April 15, 2009.
Influenza B (B/Victoria/02/87 and B/Yamagata/16/88 lineages) [0]
    Victoria lineage [0]
  • No influenza B viruses from Texas have been characterized since April 15, 2009.
    Yamagata lineage [0]
  • No influenza B viruses from Texas have been characterized since April 15, 2009.

The national antigenic characterization and antiviral resistance testing results may be found in the CDC weekly flu report at The DSHS Laboratory sends a representative sample of influenza viruses to the CDC throughout the flu season.

Antiviral Resistance

Since June 9, 2009, CDC has reported antiviral resistance testing results on 110 novel influenza A (H1N1) isolates received from multiple Texas laboratories since April 26, 2009.
Isolates Tested (n) Resistant Viruses,
Number (%)
Isolates Tested (n) Resistant Viruses,
Number (%)
Oseltamivir Zanamivir Adamantanes
Influenza A (H1N1) (novel) 110 2 (2%) 0 (0) 42 42 (100%)
Influenza A (H3N2) 0 0 (0) 0 (0) 0 0 (0)
Influenza A (H1N1) (seasonal) 0 0 (0) 0 (0) 0 0 (00)
Influenza B 0 0 (0) 0 (0) N/A* N/A*

                                    *Adamantanes are not effective against influenza B viruses.

CDC has issued interim recommendations for use of antiviral medications in the 2009-10 influenza season. Those recommendations are available at:

Influenza–Associated Pediatric Mortality

One influenza-associated pediatric death was reported during week 40. The child was an 11-year-old resident of HSR 2/3 with significant underlying medical conditions. The child was not vaccinated for influenza for the current season. Texas has reported one influenza-associated pediatric fatality during the 2009-10 influenza season. There were 15 influenza-associated pediatric deaths reported from April 26, 2009 to October 3, 2009.

School Closures and Institutional Outbreaks

Several school closures were reported during week 40. Schools in Ellis (1 school), Freestone (3), Hunt (3), Hutchinson (1), Leon (3), and Wilbarger (1) counties closed due to ILI. Four schools in Denton County closed due to ILI and influenza A. Three schools in Hopkins County closed due to high absenteeism. DSHS has issued guidance for cases of ILI and novel influenza A (H1N1) in summer camps, schools, and congregate facilities. Please see for more information. For information on school closures, please see the Texas Education Agency's website at

U.S. Outpatient Influenza-like Illness Surveillance Network

Seventy-five providers in Texas reported data to the U.S. Outpatient Influenza-like Illness Surveillance Network (ILINet) (formerly known as the U.S. Influenza Sentinel Provider Surveillance System) on patients with influenza-like illness (ILI) and total patients seen for any reason during week 40. Of these 74 providers who saw patients, 68 (92%) saw at least one patient with ILI. Of all patient visits during this week, 12.96% were due to ILI. The ILI baseline for HHS Region 6 (Arkansas, Louisiana, New Mexico, Oklahoma, and Texas) of the United States was 4.6% for the 2008-2009 season. The baseline is the mean percentage of patient visits for ILI during non-influenza weeks for the previous three seasons plus two standard deviations.
Percentage of Visits for Influenza–Like Illness Reported by the US Outpatient Influenza–Like Illness Surveillance Network (ILINet) in Texas as of 10/15/2009 4:42:58 PM
Week # Reporting Age 0-4 Age 5-24 Age 25-49 Age 50-64 Age over 64 Total ILI Total Patients % ILI
2009-31 59 56 92 95 9 252 17727 1.42%
2009-32 57 56 109 81 9 255 17856 1.43%
2009-33 54 46 111 124 13 294 19431 1.51%
2009-34 53 74 267 99 4 444 19483 2.28%
2009-35 52 128 426 99 7 660 20426 3.23%
2009-36 52 132 614 177 10 933 20400 4.57%
2009-37 51 249 1103 307 16 1675 25033 6.69%
2009-38 49 190 663 105 13 971 14158 6.86%
2009-39 47 298 1405 494 14 2211 23619 9.36%
2009-40 75 1005 1870 401 153 42 3471 26775 12.96%

ILI Percentage in Texas Chart
ILI Data in Texas Chart

National Influenza Activity Map

The current U.S. flu weekly report (FluView) may be found at

For more information on flu surveillance activities in the State of Texas, please visit our main surveillance page.

Influenza in Texas Map

1Influenza activity level corresponds to current MMWR week only and does not reflect previous weeks' activity.
2The majority of influenza cases are not reportable by law to the Texas Department of State Health Services. This map contains data from sentinel sites and does not represent all influenza cases in the state.
3Positive laboratory results are reported according to specimen collection date or date received in the lab if the former is unknown.

Texas Department of State Health Services - Infectious Disease Control Unit
1100 West 49th Street, Suite T801, Mail Code: 1960 PO BOX 149347 - Austin, TX 78714-9347
(512) 458-7676 - Fax: (512) 458-7616 -

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Last updated January 10, 2011