2009 - 2010 Texas Influenza Surveillance Information
Influenza Surveillance Report for MMWR week 11
The influenza (flu) activity level for Texas for the week ending March 20, 2010 was “sporadic” For definitions of flu activity levels please see http://www.cdc.gov/flu/weekly/fluactivity.htm. During week 11, 18 (4.8%) 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 below the regional baseline during week 11.
Reports from Health Service Regions
Reports were received from all Health Service Regions (HSRs) for week 11. HSR 6/5S reported an increased number of positive influenza A tests during week 11; however, the overall flu activity level remained the same compared to week 10. HSRs 1, 4/5N, 8, and 9/10 reported the same level of flu activity compared to week 10. HSRs 2/3, 7, and 11 reported a decreased level of flu activity compared to week 10. For a map of Health Service Regions please visit the following website: http://www.dshs.state.tx.us/regions/state.shtm
During week 11, seven hospital laboratories and public health agencies across Texas reported conducting a total of 372 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). Seventy-one percent 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.
Since June 9, 2009, CDC has reported antigenic characterization results from 47 novel influenza A (H1N1) viruses, 1 seasonal influenza A (H1N1) virus, and 1 influenza B virus received from the Texas Department of State Health Services (DSHS) Laboratory.
Novel Influenza A (H1N1) [ 47 ]
Influenza A (H3N2) 
- All 47 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 (H1N1) seasonal 
- No influenza A (H3N2) viruses from Texas have been characterized since June 9, 2009.
Influenza B (B/Victoria/02/87 and B/Yamagata/16/88 lineages) 
- One seasonal influenza A (H1N1) virus from Texas has been characterized as A/Brisbane/59/2007-like (H1N1), the influenza A/H1 component of the 2009-2010 seasonal influenza vaccine for the Northern Hemisphere.
- Victoria lineage 
- " One influenza B virus from Texas has been characterized as B/Brisbane/60/2008-like, the influenza B component of the 2009-2010 seasonal influenza vaccine for the Northern Hemisphere.
Yamagata lineage 
- No influenza B viruses from Texas have been characterized since June 9, 2009.
The national antigenic characterization and antiviral resistance testing results may be found in the CDC weekly flu report at www.cdc.gov/flu/weekly/. The DSHS Laboratory sends a representative sample of influenza viruses to the CDC throughout the flu season.
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)
|Isolates Tested (n)
|Influenza A (H1N1) (novel)
|Influenza A (H3N2)
|Influenza A (H1N1) (seasonal
*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: http://www.cdc.gov/h1n1flu/recommendations.htm.
Influenza–Associated Pediatric Mortality
Please see http://www.dshs.state.tx.us/txflu/splash/news_media.html for more information.
School Closures and Institutional Outbreaks
No institutional outbreaks or school closures were reported during week 11. DSHS has issued guidance for cases of ILI and novel influenza A (H1N1) in summer camps, schools, and congregate facilities. Please see www.texasflu.org for more information. For information on school closures, please see the Texas Education Agency's website at http://www.tea.state.tx.us/index4.aspx?id=5402.
U.S. Outpatient Influenza-like Illness Surveillance Network
Fifty-four 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 11. Of the 51 providers who saw patients, 20 (39%) saw at least one patient with ILI. Of all patient visits during this week, 2.10% were due to ILI. The ILI baseline for HHS Region 6 (Arkansas, Louisiana, New Mexico, Oklahoma, and Texas) of the United States is 4.6% for the 2009-2010 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.
National Influenza Activity Map
The current U.S. flu weekly report (FluView) may be found at http://www.cdc.gov/flu/weekly/fluactivity.htm.
*This map indicates geographic spread and does not measure the severity of influenza activity.
For more information on flu surveillance activities in the State of Texas, please visit our main surveillance page.
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.