2008 - 2009 Texas Influenza Surveillance Information
Influenza Surveillance Report for MMWR Week 15
The influenza (flu) activity level for Texas for the week ending April 18, 2009 was “local.” During week 15, one (0.4%) specimen tested by NREVSS laboratories in Texas was positive for influenza. The percentage of visits for influenza-like illness as reported by ILINet providers in Texas was below the regional baseline.
Reports from Health Service Regions
Reports were received from all Health Service Regions (HSRs) for week 15. HSRs 4/5N and 6/5S reported the same level of flu activity compared to week 14. All other HSRs reported a decreased level of flu activity compared to week 14. For a map of Health Service Regions, please visit the following website:
http://www.dshs.state.tx.us/regions/state.shtm
Laboratory Results
During week 15, six hospital laboratories and public health agencies across Texas reported conducting a total of 263 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). Of the 211 antigen detection tests that were performed, one specimen from Harris County was positive for influenza A/not subtyped. No positive PCR test results were reported during week 15. Two reports of culture-confirmed seasonal influenza were received from public health laboratories in Austin and Houston. The specimens were submitted from Harris and Lubbock counties, and both were positive for influenza B. Positive point-of-care rapid tests for influenza were reported by providers throughout the state (see county map below).
Novel Influenza A Virus Infections
Two novel influenza A virus infections in Texas residents were reported to the Centers for Disease Control and Prevention (CDC) during week 15. These infections were reported in two 16-year-old residents of Guadalupe County; their onsets of symptoms occurred during week 14 (week ending April 11, 2009) and week 15 (week ending April 18, 2009), respectively. The specimens were collected and the viruses identified through routine influenza surveillance activities; the isolates were further identified by CDC as swine influenza A (H1N1) viruses. Thorough case and contact investigations are ongoing. Please see http://www.cdc.gov/flu/swine/ for more information on the current investigation.
Antigenic Characterization
CDC has reported antigenic characterization results from 48 influenza isolates [20 influenza A/H1, 6 influenza A/H3, and 22 influenza B viruses] received from the DSHS Laboratory since the beginning of the 2008–09 flu season.
Influenza A/H1 [20]
- All 20 viruses were characterized as A/Brisbane/59/2007, the influenza A/H1 component of the 2008–09 influenza vaccine for the Northern Hemisphere.
Influenza A/H3 [6]
- All 6 viruses were characterized as A/Brisbane/10/2007, the influenza A/H3 component of the 2008-09 influenza vaccine for the Northern Hemisphere.
Influenza B (B/Victoria/02/87 and B/Yamagata/16/88 lineages) [22]
Victoria lineage [15] - Fifteen of the influenza B viruses were characterized as belonging to the B/Victoria lineage.
Yamagata lineage [7]
- Seven viruses were characterized as B/Florida/4/2006, the influenza B component for the 2008-09 influenza vaccine for the Northern Hemisphere.
Antiviral Resistance
Since September 28, 2008, 21 seasonal influenza A/H1 isolates, 6 influenza A/H3 isolates, and 21 influenza B isolates from the DSHS laboratory have been tested by CDC for antiviral resistance.
| |
Isolates Tested (n) |
Resistant Viruses,
Number (%)
|
Isolates Tested (n) |
Resistant Viruses,
Number (%)
|
| Oseltamivir |
Zanamivir |
Adamantanes |
| Influenza A/H1 |
21 |
21 (100%) |
0 (0) |
21 |
0 (0) |
| Influenza A/H3 |
6 |
0 (0) |
0 (0) |
6 |
6 (100%) |
| Influenza B |
21 |
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 2008-09 influenza season. Those recommendations are available at: http://www.cdc.gov/flu/professionals/antivirals/index.htm..
Influenza–Associated Pediatric Mortality
No influenza-associated pediatric fatalities were reported during week 15. Texas has reported ten influenza-associated pediatric fatalities during the 2008-09 influenza season.
School Closures and Institutional Outbreaks
No school closures or institutional outbreaks were reported in week 15.
U.S. Outpatient Influenza-like Illness Surveillance Network
Fifty-three 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 15. Of the 52 providers who reported seeing patients during week 15, 18 (35%) saw at least one patient with ILI. Of all patient visits during this week, 1.83% were due to ILI. The ILI baseline for the West South Central Region (Arkansas, Louisiana, Oklahoma, and Texas) of the United States is 4.8% 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 4/24/2009 6:01:01 PM |
| Week |
# Reporting |
Age 0-4 |
Age 5-24 |
Age 25-64 |
Age over 64 |
Total ILI |
Total Patients |
% ILI |
| 2008-40 |
78 |
84 |
133 |
127 |
22 |
366 |
20333 |
1.80 |
| 2008-41 |
78 |
114 |
163 |
124 |
19 |
420 |
20105 |
2.09 |
| 2008-42 |
79 |
107 |
156 |
90 |
7 |
360 |
19746 |
1.82 |
| 2008-43 |
79 |
120 |
152 |
106 |
20 |
398 |
19740 |
2.02 |
| 2008-44 |
80 |
136 |
199 |
103 |
26 |
464 |
20737 |
2.24 |
| 2008-45 |
78 |
110 |
111 |
122 |
27 |
370 |
20835 |
1.78 |
| 2008-46 |
73 |
110 |
106 |
103 |
23 |
342 |
19771 |
1.73 |
| 2008-47 |
75 |
137 |
143 |
122 |
19 |
421 |
19806 |
2.13 |
| 2008-48 |
79 |
131 |
132 |
125 |
37 |
425 |
16905 |
2.51 |
| 2008-49 |
77 |
143 |
159 |
153 |
24 |
479 |
20343 |
2.35 |
| 2008-50 |
75 |
133 |
146 |
108 |
28 |
415 |
19330 |
2.15 |
| 2008-51 |
69 |
172 |
177 |
175 |
24 |
548 |
17531 |
3.13 |
| 2008-52 |
76 |
194 |
153 |
154 |
34 |
535 |
13431 |
3.98 |
| 2008-53 |
77 |
176 |
141 |
165 |
46 |
528 |
15222 |
3.47 |
| 2009-01 |
78 |
162 |
182 |
188 |
38 |
570 |
18518 |
3.08 |
| 2009-02 |
77 |
178 |
287 |
235 |
41 |
741 |
20094 |
3.69 |
| 2009-03 |
78 |
174 |
468 |
341 |
43 |
1026 |
22951 |
4.47 |
| 2009-04 |
78 |
260 |
679 |
332 |
47 |
1318 |
24244 |
5.44 |
| 2009-05 |
73 |
282 |
883 |
465 |
40 |
1670 |
24590 |
6.79 |
| 2009-06 |
79 |
301 |
964 |
391 |
59 |
1715 |
24162 |
7.10 |
| 2009-07 |
79 |
320 |
814 |
316 |
57 |
1507 |
25873 |
5.82 |
| 2009-08 |
73 |
221 |
552 |
283 |
57 |
1113 |
24526 |
4.54 |
| 2009-09 |
76 |
194 |
422 |
244 |
71 |
931 |
22111 |
4.21 |
| 2009-10 |
79 |
221 |
324 |
212 |
77 |
834 |
22341 |
3.73 |
| 2009-11 |
74 |
167 |
268 |
178 |
58 |
671 |
19156 |
3.50 |
| 2009-12 |
68 |
109 |
150 |
179 |
18 |
456 |
19962 |
2.28 |
| 2009-13 |
67 |
114 |
141 |
163 |
16 |
434 |
17659 |
2.46 |
| 2009-14 |
68 |
158 |
192 |
232 |
51 |
633 |
18858 |
3.36 |
| 2009-15 |
53 |
57 |
104 |
132 |
19 |
312 |
17095 |
1.83 |
National Influenza Activity Map
The map showing influenza activity in the United States for MMWR week 15 is displayed below. The current U.S. flu weekly report may be found at: here.
 *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.
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