2010-2011 DSHS Flu Report Week 42

2010 - 2011 Texas Influenza Surveillance Information

During week 42 in Texas:

• The influenza (flu) activity level (geographic spread of influenza) for Texas was "local" and the ILINet Activity Level Indicator was "minimal". For more information please see http://www.cdc.gov/flu/weekly/fluactivity.htm and the national FluView weekly report at http://www.cdc.gov/flu/weekly/.
• Twenty-nine (4.4%) specimens tested by NREVSS laboratories in Texas were positive for influenza. One specimen was positive for 2009 influenza A (H1N1), four specimens were positive for influenza A (H3N2), and one specimen was positive for influenza A (not subtyped) 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 42. HSRs 2/3, 7, 8, 9/10, and 11 reported an increased level of flu activity compared to week 41. HSRs 1, 4/5N, and 6/5S reported the same level of flu activity compared to week 41. For a map of Health Service Regions please visit the following website: http://www.dshs.state.tx.us/regions/state.shtm 

Laboratory Results

Influenza

During week 42, nine hospital laboratories and public health agencies across Texas reported conducting a total of 662 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 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.  

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

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 42 are summarized below.

Antigenic Characterization

Since July 2010, CDC has reported antigenic characterization results from 1 influenza A (H1N1) virus and 2 influenza B viruses 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 [2]
• Victoria lineage [2]
  Two influenza B viruses were 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 www.cdc.gov/flu/weekly/. 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 42. 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. 

Cases of influenza-associated pediatric mortality (children <18 years of age) are reportable year-round and by law in Texas. Please see http://www.dshs.state.tx.us/idcu/investigation/conditions/ 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 42.

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

An influenza outbreak occurred in an elementary school in HSR 4/5N during week 42. Specimens collected from several ill students were positive for influenza B by PCR testing. The school did not close, and no other area schools were affected. Information on the control of influenza in various settings may be found on the CDC website at http://www.cdc.gov/flu/professionals/infectioncontrol/. 

U.S. Outpatient Influenza-like Illness Surveillance Network

Seventy-seven 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 42. Of the 77 providers who saw patients, 44 (57%) saw at least one patient with ILI. Of all patient visits during this week, 3.40% 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). 

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.  

International Influenza Activity Map

The CDC compiles information from several sources and releases an international influenza summary. This report can be found at http://www.cdc.gov/flu/international/activity.htm. 

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.

2010 - 2011 Texas Influenza Surveillance Information --- Flu Reports

For the week ending: 10/09/10; 10/16/10; 10/23/10; 10/30/10; 11/06/10; 11/13/10; 11/20/10; 11/27/10; 12/04/10; 12/11/10; 12/18/10; 12/25/10; 01/01/11; 01/08/11; 01/15/11; 01/22/11; 01/29/11;

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