2010-2011 DSHS Flu Report Week 4

2010 - 2011 Texas Influenza Surveillance Information

During week 4 in Texas:

• The influenza (flu) activity level (geographic spread of influenza) for Texas was "widespread" and the ILINet Activity Level Indicator (intensity of influenza-like illness) was "high". 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/.
• Five hundred seventy-six (29.1%) specimens tested by NREVSS laboratories in Texas were positive for influenza. Fifteen specimens were positive for 2009 influenza A (H1N1), 97 specimens were positive for influenza A (H3N2), 26 specimens were positive for influenza A (not subtyped), and 28 specimens were positive for influenza B by viral culture or PCR testing; the remaining positive results were obtained by antigen detection test.
• The percentage of visits for influenza-like illness as reported by ILINet providers in Texas exceeded the regional baseline and the state baseline.
• No influenza-associated pediatric deaths were reported.
• Two influenza outbreaks were reported in long term care facilities in Regions 7 and 8.

Reports from Health Service Regions

Reports were received from all Health Service Regions (HSRs) for week 4. HSRs 4/5N, 6/5S, 7, 8 and 11 reported an increased level of flu activity compared to week 3. HSRs 1 and 9/10 reported the same level of flu activity compared to week 3. HSR 2/3 reported a decreased level of flu activity compared to week 3. 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 4, seven hospital laboratories and public health agencies across Texas reported conducting a total of 1,982 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). Eighty 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 4 are summarized below.

Antigenic Characterization

Since July 2010, CDC has reported antigenic characterization results from 3 influenza A (H1N1) viruses, 14 influenza A (H3N2) viruses, and 9 influenza B viruses received from the Texas Department of State Health Services (DSHS) Laboratory.

• Influenza A (H1N1) [3]
  Three viruses were 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) [14]
  Fourteen viruses were related to A/Perth/16/2009-like (H3N2), the influenza A (H3N2) component of the 2010-2011 influenza vaccine for the Northern Hemisphere.
• Influenza B [9]
  • Victoria lineage [9]
    Nine 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

No Texas influenza isolates tested so far in the 2010-2011 influenza season have demonstrated resistance to oseltamivir or zanamivir. Resistance to the adamantanes has been detected in most of the 2009 influenza A (H1N1) and influenza A (H3N2) isolates tested over the last two influenza seasons. 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 4. Three influenza-associated pediatric fatalities have been reported in Texas since the beginning of the 2010-2011 influenza season. Two deaths have been reported during calendar year 2011. 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 4.

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

One influenza outbreak in a long term care facility in HSR 7 was reported during week 4. At least 12 individuals (residents and staff) reported influenza-like illness. Three of the residents were diagnosed with influenza at a local hospital. Another influenza outbreak in a long term care facility was reported in HSR 8 during week 4. At least 15 residents had symptoms of influenza with 4 testing positive for influenza A by rapid test. Both facilities implemented control measures. 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

Sixty-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 4. Of the 63 providers who saw patients, 52 (83%) saw at least one patient with ILI. Of all patient visits during this week, 7.22% 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

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.

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; 02/05/11; 02/12/11;