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    Infectious Disease Control Unit
    Mail Code: 1960
    PO BOX 149347 - Austin, TX 78714-9347
    1100 West 49th Street, Suite T801
    Austin, TX 78714

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


2010-2011 DSHS Flu Report Week 41

2010 - 2011 Texas Influenza Surveillance Information

Please note: The 2010-2011 influenza season began on October 3, 2010. For reports from the 2009-2010 season, please see

During week 41 in Texas:

  • The influenza (flu) activity level (geographic spread of influenza) for Texas was "sporadic" and the ILINet Activity Level Indicator was "minimal". For more information please see and the national FluView weekly report at
  • Nineteen (3.9%) specimens tested by NREVSS laboratories in Texas were positive for influenza. Eight specimens were positive for influenza A (H3N2), one specimen was positive for influenza A (not subtyped), and one specimen was positive for influenza B by PCR testing; all other positive results were obtained by antigen detection test.
  • The percentage of visits for influenza-like illness as reported by ILINet providers in Texas was below the state and regional baselines.  

Reports from Health Service Regions

Reports were received from all Health Service Regions (HSRs) for week 41. HSRs 9/10 and 11 reported an increased level of flu activity compared to week 40. HSRs 1, 4/5N, 7, and 8 reported the same level of flu activity compared to week 40. HSRs 2/3 and 6/5S reported a decreased level of flu activity compared to week 40. For a map of Health Service Regions please visit the following website:

Laboratory Results


During week 41, nine hospital laboratories and public health agencies across Texas reported conducting a total of 484 influenza tests (antigen, culture, and PCR) to the National Respiratory and Enteric Virus Surveillance System (NREVSS) sponsored by the Centers for Disease Control and Prevention (CDC). Sixty-three percent of the 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. 



Influenza Testing Results Reported by Texas NREVSS Laboratories
Testing Information Week 41
No. of specimens tested 484
No. of positive specimens (%) 19 (3.9%)
Positive specimens by type/subtype
Influenza A 17 (89.5%)
          Subtyping performed 8 (47.1%)
                 A (2009 H1N1) 0 (0%)
                 A (H3N2) 0 (0%)
                 A (Seasonal H1) 8 (100%)
           Subtyping not performed 9 (52.9%)
Influenza B 2 (10.5%)

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

Other Respiratory Viruses

The NREVSS system collects information on a variety of respiratory viruses in addition to influenza including parainfluenza, respiratory syncytial virus (RSV), rhinovirus, human metapneumovirus (HMPV), and respiratory adenovirus. The results from week 41 are summarized below.



Other Respiratory Virus Results Reported by Texas NREVSS Laboratories
Virus Number of
of Tests
Adenovirus (respiratory) 3 149 9 6.04%
HMPV 3 130 0 0.00%
Parainfluenza 4 145 6 4.14%
Rhinovirus 2 128 27 21.09%
RSV 13 511 16 3.13%

Antigenic Characterization

Since July 2010, CDC has reported antigenic characterization results from 1 influenza A (H1N1) virus and 1 influenza B virus received from the Texas Department of State Health Services (DSHS) Laboratory. 

  • Influenza A (H1N1) [1]
    One virus was related to A/California/07/2009-like (H1N1), the influenza A (H1N1) component of the 2010-2011 influenza vaccine for the Northern Hemisphere.
  • Influenza A (H3N2) [0]
    No influenza A (H3N2) viruses from the Texas DSHS Laboratory have been characterized since 2009.
  • Influenza B [1]
    • Victoria lineage [1]
      One influenza B virus was related to B/Brisbane/60/2008-like, the influenza B component of the 2010-2011 influenza vaccine for the Northern Hemisphere.
    • Yamagata lineage [0]
      No influenza B viruses of the Yamagata lineage have been characterized since 2009. 

The national antigenic characterization and antiviral resistance testing results may be found in the final 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 July 2010, CDC has not reported any antiviral resistance testing results on influenza isolates received from Texas laboratories. 

Influenza–Associated Pediatric Mortality

No new influenza-associated pediatric fatalities were reported during week 41. There have been no influenza-associated pediatric fatalities reported in Texas since the beginning of the 2010-2011 influenza season. Six deaths have been reported during calendar year 2010. Please see the table below for more information. 


Influenza-Associated Pediatric Deaths in Texas Residents by Type, Subtype, and Month
Month of
Pediatric death,
Influenza Type A Total
Type B
All Influenza
Types and
Subtypes Total
Influenza A,
All Subtypes
H3N2 Not Subtyped
January 0 0 0 0 0 0 0
February 1 0 0 1 2 0 2
March 2 0 0 1 3 0 3
April 0 0 0 0 0 0 0
May 0 0 0 0 0 0 0
June 0 0 0 1 1 0 1
July 0 0 0 0 0 0 0
August 0 0 0 0 0 0 0
September 0 0 0 0 0 0 0
October 0 0 0 0 0 0 0
Unknown 0 0 0 0 0 0 0
Total 3 0 0 3 6 0 6

Cases of influenza-associated pediatric mortality (children <18 years of age) are reportable year-round and by law in Texas. Please see for more information.  

Influenza-Associated Deaths in Pregnant and Postpartum Women

No new influenza-associated deaths were reported in pregnant or postpartum women during week 41.

DSHS is requesting reporting of influenza-associated deaths in pregnant or postpartum (up to 6 weeks) women during the summer of 2010 and continuing throughout the 2010-2011 influenza season. There has been 1 death reported since the beginning of the summer 2010. All influenza types and subtypes should be reported; a positive rapid influenza test is sufficient for confirmation. 

School Closures and Institutional Outbreaks

No institutional outbreaks or school closures were reported during week 41. Information on the control of influenza in various settings may be found on the CDC website at  

U.S. Outpatient Influenza-like Illness Surveillance Network

Seventy-one 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 41. Of the 70 providers who saw patients, 41 (59%) saw at least one patient with ILI. Of all patient visits during this week, 3.06% were due to ILI. The Texas ILI baseline is 6.09% for the 2010-2011 season. The ILI baseline for HHS Region 6 (Arkansas, Louisiana, New Mexico, Oklahoma, and Texas) of the United States is 4.9% for the 2010-2011 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. The baselines displayed on the graph below were calculated for the official influenza reporting season only (approximately October to May).

Percentage of Visits for Influenza–Like Illness Reported by
the US Outpatient Influenza–Like Illness Surveillance Network (ILINet) in Texas
10/22/2010 9:30:00 AM
Week # Reporting Age 0-4 Age 5-24 Age 25-49 Age 50-64 Age 65 and older Total ILI Total Patients % ILI
2011-40 70 303 273 172 32 21 801 24997 3.20%
2011-41 71 286 232 118 25 12 673 22014 3.06%


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

Influenza in USA Map

*This map indicates geographic spread and does not measure the severity of influenza activity. 

International Influenza Activity Map

The CDC compiles information from several sources and releases an international influenza summary. This report can be found at

International Co-circulation of Seasonal Influenza Map


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.

Last updated March 21, 2011