2007 - 2008 Texas Influenza Surveillance Information
Influenza Surveillance Report for MMWR Week 18
The influenza (flu) activity level for Texas for the week ending May 3, 2008 was “sporadic.” Sporadic activity indicates that isolated reports of laboratory–confirmed influenza along with influenza–like illness (ILI) have been reported. During week 18, eight (5.8%) specimens tested by NREVSS laboratories in Texas were positive for influenza. The percentage of visits due to influenza–like illness (ILI) as reported by SPSN providers in Texas was below the regional baseline. Flu activity in Texas in week 18 continued to decrease in all regions.
Reports from Health Service Regions
Reports were received from all Health Service Regions (HSRs) for week 18. All HSRs reported a decrease in overall flu activity compared to week 17. 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 18, seven hospital laboratories and public health agencies across Texas reported conducting a total of 139 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 127 antigen detection tests performed, five were positive for influenza A/not subtyped and two were positive for influenza B. These positive results were reported from Bexar and Nueces counties. Scott and White Hospital Laboratory in Bell County and Texas Children’s Hospital in Harris County each reported one culture positive for influenza B. Additional positive results from point–of–care rapid flu tests were reported by providers throughout the state (see Texas map).
Antigenic Characterization
CDC has reported antigenic characterization results from 37 influenza isolates [8 influenza A/H1, 25 influenza A/H3, and 4 influenza B viruses] received from the DSHS Laboratory since the beginning of the 2007–08 flu season.
Influenza A/H1 [8]
- Eight (100%) of the eight viruses were characterized as A/Solomon Islands/3/2006, the influenza A/H1 component of the 2007–08 influenza vaccine for the Northern Hemisphere.
Influenza A/H3 [25]
- Three (12%) of the 25 viruses were characterized as A/Wisconsin/67/2005-like, the influenza A/H3 component of the 2007-08 influenza vaccine for the Northern Hemisphere.
- Twenty–one (84%) of the 25 viruses were characterized as A/Brisbane/10/2007–like. A/Brisbane/10/2007 is a recent antigenic variant which evolved from A/Wisconsin/67/2005–like.
- One (4%) of the 25 viruses showed somewhat reduced titers with antisera produced against A/Wisconsin/67/2005 and A/Brisbane/10/2007.
Influenza B (B/Victoria/02/87 and B/Yamagata/16/88 lineages) [4]
Victoria lineage [0] - The influenza B component for the 2007–08 influenza vaccine is a B/Malaysia/2506/2004–like virus, belonging to the B/Victoria lineage.
Yamagata lineage [4]
- Four (100%) of the four viruses were identified as belonging to the B/Yamagata lineage of viruses.
These results are very similar to national antigenic characterization results. The national 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.
Influenza–Associated Pediatric Mortality
No influenza–associated pediatric fatalities were reported during week 18. As of week 18, Texas has reported seven influenza-associated pediatric deaths in the 2007–08 influenza season.
School Closures and Institutional Outbreaks
No school closures or institutional outbreaks were reported during week 18.
Sentinel Provider Surveillance Network
Seventy–seven sentinel providers in Texas reported data to the U.S. Influenza Sentinel Provider Surveillance System (SPSN) on patients with influenza–like illness (ILI) and total patients seen for any reason during week 18; of the 74 providers who reported seeing patients, 25 (33.8%) providers saw at least one patient with ILI. Of all patient visits during this week, 1.57% were due to ILI. The ILI baseline for the West South Central Region (Arkansas, Louisiana, Oklahoma, and Texas) of the United States is 4.3% for the 2007-2008 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 Influenza–Like Illness (ILI) Reported by Sentinel Providers in Texas as of (5/13/2008 12:04:50 PM) |
Week |
# Reporting |
Age 0-4 |
Age 5-24 |
Age 25-64 |
Age over 64 |
Total ILI |
Total Patients |
% ILI |
2007-40 |
84 |
256 |
163 |
151 |
49 |
619 |
21410 |
2.89 |
2007-41 |
88 |
264 |
255 |
207 |
58 |
784 |
25255 |
3.10 |
2007-42 |
86 |
274 |
270 |
261 |
50 |
855 |
25776 |
3.32 |
2007-43 |
85 |
368 |
290 |
208 |
47 |
913 |
26428 |
3.45 |
2007-44 |
95 |
391 |
276 |
206 |
55 |
928 |
28213 |
3.29 |
2007-45 |
87 |
411 |
314 |
243 |
39 |
1007 |
25665 |
3.92 |
2007-46 |
79 |
442 |
306 |
215 |
65 |
1028 |
24713 |
4.16 |
2007-47 |
91 |
478 |
317 |
272 |
73 |
1140 |
22748 |
5.01 |
2007-48 |
84 |
506 |
298 |
299 |
74 |
1177 |
26193 |
4.49 |
2007-49 |
84 |
232 |
290 |
162 |
16 |
700 |
20713 |
3.38 |
2007-50 |
80 |
256 |
265 |
128 |
16 |
665 |
18711 |
3.55 |
2007-51 |
68 |
169 |
197 |
186 |
26 |
578 |
15597 |
3.71 |
2007-52 |
77 |
176 |
201 |
191 |
22 |
590 |
12436 |
4.74 |
2008-01 |
90 |
217 |
302 |
332 |
29 |
880 |
16520 |
5.33 |
2008-02 |
97 |
373 |
500 |
630 |
117 |
1620 |
25891 |
6.26 |
2008-03 |
81 |
289 |
518 |
370 |
36 |
1213 |
21940 |
5.53 |
2008-04 |
87 |
369 |
886 |
650 |
54 |
1959 |
23306 |
8.41 |
2008-05 |
96 |
601 |
1208 |
954 |
158 |
2921 |
29106 |
10.04 |
2008-06 |
96 |
557 |
1128 |
951 |
112 |
2748 |
28337 |
9.37 |
2008-07 |
100 |
529 |
1037 |
808 |
124 |
2498 |
27849 |
8.97 |
2008-08 |
99 |
423 |
789 |
769 |
92 |
2073 |
26573 |
7.80 |
2008-09 |
91 |
421 |
576 |
690 |
83 |
1770 |
26637 |
6.64 |
2008-10 |
91 |
344 |
466 |
494 |
80 |
1384 |
24965 |
5.54 |
2008-11 |
82 |
259 |
366 |
385 |
39 |
1049 |
18473 |
5.68 |
2008-12 |
82 |
157 |
169 |
113 |
26 |
465 |
14055 |
3.31 |
2008-13 |
88 |
186 |
244 |
292 |
24 |
746 |
19842 |
3.76 |
2008-14 |
93 |
307 |
266 |
325 |
78 |
976 |
24292 |
4.02 |
2008-15 |
88 |
263 |
226 |
257 |
90 |
836 |
25841 |
3.24 |
2008-16 |
92 |
232 |
253 |
290 |
54 |
829 |
26211 |
3.16 |
2008-17 |
76 |
88 |
120 |
132 |
13 |
353 |
17971 |
1.96 |
2008-18 |
77 |
75 |
90 |
92 |
1 |
258 |
16388 |
1.57 |
The map showing influenza activity in the United States for MMWR week 18 is displayed below. The current U.S. flu weekly report may be found here.
For more information on flu surveillance activities in the State of Texas, please visit our main surveillance page.
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Texas Department of State Health Services - Infectious Disease Control Unit
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