2009 - 2010 Texas Influenza Surveillance Information
Influenza Surveillance Report for MMWR Week 40
The influenza (flu) activity level for Texas for the week ending October 10, 2009 was “widespread.” For definitions of flu activity levels please see http://www.cdc.gov/flu/weekly/fluactivity.htm. During week 40, 1,029 (31.8%) 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 above the regional baseline during week 40.
Reports from Health Service Regions
Reports were received from all Health Service Regions (HSRs) for week 40. HSRs 1, 6/5S, 8, and 9/10 reported an increased level of flu activity compared to week 39. HSRs 2/3 and 11 reported the same level of flu activity compared to week 39. HSRs 4/5N and 7 reported a decreased level of flu activity compared to week 39. For a map of Health Service Regions please visit the following website: www.dshs.state.tx.us/regions/state.shtm Laboratory Results
During week 40, fourteen hospital laboratories and public health agencies across Texas reported conducting a total of 3,239 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). The majority (69%) 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.
Testing Information |
Week 40 |
No. of specimens tested |
3,239 |
No. of positive specimens (%) |
1,029 (31.8%) |
Positive specimens by type/subtype |
Influenza A |
1,025 (99.6%) |
Subtyping performed |
230 (22.4%) |
A (novel H1N1) |
230 (100%) |
A (H3) |
0 (0%) |
A (Seasonal H1) |
0 (0%) |
Subtyping not performed |
795 (77.6%) |
Influenza B |
(0.4%) |
Additional influenza test results (rapid tests, culture, PCR) were reported from providers and public health departments throughout the state (see county map below).
Novel Influenza A Virus Infections
Please see the Texas Department of State Health Services (DSHS) novel influenza website (http://www.texasflu.org) and the CDC website (http://www.cdc.gov/h1n1flu/) for more information. Data collection for confirmed novel influenza A (H1N1) hospitalizations, intensive care unit (ICU) admissions, and deaths began in Texas on September 20, 2009. Forty-seven confirmed novel influenza A (H1N1) deaths were reported in Texas residents and one child from Mexico who died in HSR 6/5S prior to September 20, 2009 (these deaths are included in the cumulative data table below). The table below summarizes the current data by Health Service Region. For more data, please see www.dshs.state.tx.us/txflu/splash/news_media.html.
Cumulative Surveillance Case Summary for Novel Influenza A (H1N1) by Health Service Region and County as of 10/10/2009 |
Health Service Region or County |
Hospitalizations* |
Intensive Care Unit (ICU) Admissions* |
Deaths** |
Region 1 Total |
6 |
4 |
2 |
Region 2/3 Total |
146 |
15 |
11 |
Region 4/5N Total |
34 |
8 |
3 |
Region 6/5S Total |
86 |
21 |
12 |
Region 7 Total |
38 |
6 |
8 |
Region 8 Total |
59 |
10 |
14 |
Region 9/10 Total |
19 |
1 |
8 |
Region 11 Total |
99 |
27 |
24 |
Texas Total |
487 |
92 |
82 |
*Reporting for hospitalizations and ICU admissions began on 9/20/2009. ICU admissions are included in the hospitalization totals. **Reporting for deaths began 4/15/2009 and includes a child from Mexico.
Antigenic Characterization
Since June 9, 2009, CDC has reported antigenic characterization results from 8 novel influenza A (H1N1) viruses received from the Texas Department of State Health Services (DSHS) Laboratory since April 26, 2009. Influenza A (H1N1) [8]
- All 8 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 (H3N2) [0]
- No influenza A (H3N2) viruses from Texas have been characterized since April 15, 2009.
Influenza A (H1N1) seasonal [0]
- No seasonal influenza A (H1N1) viruses from Texas have been characterized since April 15, 2009.
Influenza B (B/Victoria/02/87 and B/Yamagata/16/88 lineages) [0]
Victoria lineage [0] - No influenza B viruses from Texas have been characterized since April 15, 2009.
Yamagata lineage [0]
- No influenza B viruses from Texas have been characterized since April 15, 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.
Antiviral Resistance
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.
Flu Types/Subtypes |
Isolates Tested (n) |
Resistant Viruses, Number (%)
|
Isolates Tested (n) |
Resistant Viruses, Number (%)
|
Oseltamivir |
Zanamivir |
Adamantanes |
Influenza A (H1N1) (novel) |
110 |
2 (2%) |
0 (0) |
42 |
42 (100%) |
Influenza A (H3N2) |
0 |
0 (0) |
0 (0) |
0 |
0 (0) |
Influenza A (H1N1) (seasonal) |
0 |
0 (0) |
0 (0) |
0 |
0 (00) |
Influenza B |
0 |
0 (0) |
0 (0) |
N/A* |
N/A* |
*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
One influenza-associated pediatric death was reported during week 40. The child was an 11-year-old resident of HSR 2/3 with significant underlying medical conditions. The child was not vaccinated for influenza for the current season. Texas has reported one influenza-associated pediatric fatality during the 2009-10 influenza season. There were 15 influenza-associated pediatric deaths reported from April 26, 2009 to October 3, 2009. School Closures and Institutional Outbreaks
Several school closures were reported during week 40. Schools in Ellis (1 school), Freestone (3), Hunt (3), Hutchinson (1), Leon (3), and Wilbarger (1) counties closed due to ILI. Four schools in Denton County closed due to ILI and influenza A. Three schools in Hopkins County closed due to high absenteeism. 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
Seventy-five 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 40. Of these 74 providers who saw patients, 68 (92%) saw at least one patient with ILI. Of all patient visits during this week, 12.96% were due to ILI. The ILI baseline for HHS Region 6 (Arkansas, Louisiana, New Mexico, Oklahoma, and Texas) of the United States was 4.6% for the 2008-2009 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.
Percentage of Visits for Influenza–Like Illness Reported by the US Outpatient Influenza–Like Illness Surveillance Network (ILINet) in Texas as of 10/15/2009 4:42:58 PM |
Week |
# Reporting |
Age 0-4 |
Age 5-24 |
Age 25-49 |
Age 50-64 |
Age over 64 |
Total ILI |
Total Patients |
% ILI |
2009-31 |
59 |
56 |
92 |
95 |
9 |
252 |
17727 |
1.42% |
2009-32 |
57 |
56 |
109 |
81 |
9 |
255 |
17856 |
1.43% |
2009-33 |
54 |
46 |
111 |
124 |
13 |
294 |
19431 |
1.51% |
2009-34 |
53 |
74 |
267 |
99 |
4 |
444 |
19483 |
2.28% |
2009-35 |
52 |
128 |
426 |
99 |
7 |
660 |
20426 |
3.23% |
2009-36 |
52 |
132 |
614 |
177 |
10 |
933 |
20400 |
4.57% |
2009-37 |
51 |
249 |
1103 |
307 |
16 |
1675 |
25033 |
6.69% |
2009-38 |
49 |
190 |
663 |
105 |
13 |
971 |
14158 |
6.86% |
2009-39 |
47 |
298 |
1405 |
494 |
14 |
2211 |
23619 |
9.36% |
2009-40 |
75 |
1005 |
1870 |
401 |
153 |
42 |
3471 |
26775 |
12.96% |
National Influenza Activity Map
The current U.S. flu weekly report (FluView) may be found at http://www.cdc.gov/flu/weekly/fluactivity.htm. For more information on flu surveillance activities in the State of Texas, please visit our main surveillance page.
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