2011-2012 DSHS Flu Report Week 19

Current Flu Activity Report in PDF Format

Please note: The 2011-2012 influenza season began on October 2, 2011. For reports from the 2010-2011 season, please see http://www.dshs.state.tx.us/idcu/disease/influenza/surveillance/2011/.

During week 19 in Texas: 

Reports from Health Service Regions

Reports were received from all Health Service Regions (HSRs) for week 19. HSRs 2/3, 4/5N, 6/5S, 7, 9/10 and 11 reported a decreased level of flu activity compared to week 18. All other HSRs reported the same level of flu activity compared to week 18. 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 19, twelve hospital laboratories and public health agencies across Texas reported conducting a total of 458 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 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).   

Influenza results (antigen detection, culture, and PCR) from NREVSS reporters for the 2011–12 season are presented in the graph below.

Other Respiratory Viruses

The NREVSS system collects information on a variety of respiratory viruses in addition to influenza including parainfluenza virus, respiratory syncytial virus (RSV), rhinovirus, human metapneumovirus (HMPV), and respiratory adenovirus. The results from week 19 are summarized below. (Three non-NREVSS laboratories also contribute to the RSV data below.)

Antigenic Characterization

Since October 2, 2011, CDC has reported antigenic characterization results from six influenza A (H3N2) viruses, ten influenza A (H1N1) viruses, and three influenza B viruses received from the Texas Department of State Health Services (DSHS) Laboratory.

• Influenza A (H1N1) [10]
  

  • Ten viruses were related to A/California/07/2009 (H1N1), the influenza A (H1N1) component of the 2011-2012 influenza vaccine for the Northern Hemisphere.
• Influenza A (H3N2) [6] 
  

  • Four (67%) viruses were related to A/Perth/16/2009 (H3N2), the influenza A (H3N2) component of the 2011-2012 influenza vaccine for the Northern Hemisphere.
  • Two (33%) viruses  showed reduced titers with antiserum produced against A/Perth/16/2009.
• Influenza B [3] 

  • Two (67%) viruses were  related to B/Brisbane/60/2008 (B/Victoria lineage). This influenza B lineage was included in the 2011-2012 influenza vaccine for the Northern Hemisphere.
  • One (33%) virus was related to B/Wisconsin/01/2010 (B/Yamagata lineage). This influenza B lineage was not included in the 2011-2012 influenza vaccine for the Northern Hemisphere.

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

Antiviral Resistance

Reports received from CDC for the 2011-2012 influenza season indicate that eleven 2009 influenza A (H1N1) isolates from Texas were positive for the mutation that confers resistance to oseltamivir. Two additional 2009 influenza A (H1N1) isolates with the mutation were identified through diagnostic testing performed at the CDC.

For more information on antiviral medications please see http://www.cdc.gov/flu/professionals/antivirals/index.htm. 

Influenza–Associated Pediatric Mortality

No influenza-associated pediatric deaths were reported during week 19. Three influenza-associated pediatric fatalities have been reported in Texas since the beginning of the 2011-2012 influenza season. 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. 

School Closures and Institutional Outbreaks

No institutional outbreaks or school closures were reported during week 19. Information on the control of influenza in various settings may be found on the CDC website athttp://www.cdc.gov/flu/professionals/infectioncontrol/. 

U.S. Outpatient Influenza-like Illness Surveillance Network

Forty 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 19. Of the 40 providers who saw patients, 23 (57%) saw at least one patient with ILI. Of all patient visits during this week, 3.10% were due to ILI. The Texas ILI baseline is 5.87% for the 2011–2012 season. The ILI baseline for HHS Region 6 (Arkansas, Louisiana, New Mexico, Oklahoma, and Texas) of the United States is 4.3% for the 2011–2012 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.

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.

2011 - 2012 Texas Influenza Surveillance Information --- Flu Reports

For the week ending: 10/08/11; 10/15/11; 10/22/11; 10/29/11; 11/05/11; 11/12/11;
11/17/11; 11/24/11; 12/03/11; 12/11/11; 12/18/11; 12/25/11; 12/31/11; 1/7/12;
1/14/12; 1/21/12; 1/28/12;  2/4/12; 2/11/12; 2/18/12; 2/25/12; 3/3/12; 3/10/12; 3/17/12;
3/24/12; 3/31/12; 4/7/12; 4/14/12; 4/21/12; 4/28/12; 5/5/12; 5/12/12;

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