2008 - 2009 Texas Influenza Surveillance Information
Influenza Surveillance Report for MMWR Week 18
The influenza (flu) activity level for Texas for the week ending May 9, 2009 was “widespread.” During week 18, 62 (3.4%) 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 below the regional baseline.
Reports from Health Service Regions
Reports were received from all Health Service Regions (HSRs) for week 18. HSRs 7 and 8 reported an increased level of flu activity compared to week 17. HSRs 1, 2/3, and 4/5N reported the same level of flu activity compared to week 17. HSRs 9/10 and 11 reported a decreased level of flu activity compared to week 17. HSR 6/5S could not determine the level of 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 1,842 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 1,287 antigen detection tests that were performed, 44 were positive for influenza A/not subtyped and 5 were positive for influenza B. The positive results were reported from Bell, Bexar, Collin, Dallas, Lubbock, and Tarrant counties. A total of 25 reports of PCR- or culture-confirmed influenza were received from public health laboratories, Scott & White Memorial Hospital in Temple, Texas Children's Hospital in Houston, NREVSS, the United States Air Force School of Aerospace Medicine (USAFSAM), and other sources for the following counties during week 18 (May 3-May 9):
Influenza A/H1 (seasonal) |
Influenza A/H3 |
Influenza A/not subtyped |
Influenza B |
Bexar County |
(none) |
Bell County |
Bell County (8) |
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Bexar County (3) |
Galveston County |
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Dallas County (3) |
McLennan County |
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Gregg County |
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Harris County (2) |
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Hidalgo County (2) |
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Taylor County |
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Travis County |
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Positive point-of-care rapid tests for influenza were reported by providers throughout the state (see county map below).
Novel Influenza A Virus Infections
A total of 19 cases of influenza A H1N1 swine confirmed by the CDC have been reported with a known illness onset in week 18 (May 3-May 9) for the following counties (listed by patient county of residence):
Influenza A H1N1 swine |
Atascosa County |
Denton County |
Hood County |
Nueces County (3) |
Tarrant County (13) |
Additional specimens have been identified by PCR testing as positive for unsubtypeable influenza A; these specimens are being forwarded to CDC or state labs for further study. This information is subject to change as more reports are received. Case investigations are ongoing, and the number of confirmed cases changes frequently. Please see the DSHS website (http://www.dshs.state.tx.us/swineflu/default.shtm) and the CDC website (http://www.cdc.gov/flu/swine/) for more information on the current investigation.
Antigenic Characterization
CDC has reported antigenic characterization results from 50 influenza isolates [20 influenza A/H1, 8 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 [8]
- All 8 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, 22 seasonal influenza A/H1 isolates, 7 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 |
22 |
22 (100%) |
0 (0) |
22 |
0 (0) |
Influenza A/H3 |
7 |
0 (0) |
0 (0) |
7 |
7 (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
One influenza-associated pediatric fatality in a Texas resident was reported during week 18. The death occurred during MMWR week 14 (week ending April 11, 2009) in a 13-year-old resident of Health Service Region 3 with significant underlying medical conditions. A specimen obtained from the child was positive for influenza B by viral culture. It is not known whether the child was vaccinated for influenza for the current season. Texas has reported eleven influenza-associated pediatric fatalities during the 2008-09 influenza season.
School Closures and Institutional Outbreaks
New school closures were reported in HSRs 2/3 (Collin, Dallas, Denton, Jack, Kaufman, Parker, Tarrant, Taylor, and Wise counties); 6 (Brazoria, Fort Bend, Galveston, Harris, Liberty, and Montgomery counties); 7 (Travis County); 8 (Bexar and Val Verde counties); and 11 (Brooks, Cameron, Hidalgo, Jim Wells, Nueces, and Webb counties) during week 18. Not all districts and/or schools within a district were closed in the counties mentioned. Several of the schools that closed in week 18 or in previous weeks reopened during week 18, partially due to changes in CDC guidance for school closures. For more information on school closures, please see http://ritter.tea.state.tx.us/swineflu/schclosings.html.
U.S. Outpatient Influenza-like Illness Surveillance Network
Fifty-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 18. Of the 53 providers who reported seeing patients during week 18, 34 (64%) providers saw at least one patient with ILI. Of all patient visits during this week, 3.44% 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 5/12/2009 10:45:42 AM |
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 |
81 |
136 |
199 |
104 |
26 |
465 |
20972 |
2.23 |
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 |
22293 |
4.18 |
2009-10 |
79 |
221 |
324 |
212 |
77 |
834 |
22341 |
3.73 |
2009-11 |
76 |
167 |
268 |
178 |
58 |
671 |
19314 |
3.47 |
2009-12 |
71 |
109 |
150 |
179 |
18 |
456 |
20622 |
2.21 |
2009-13 |
71 |
114 |
141 |
163 |
16 |
434 |
18356 |
2.36 |
2009-14 |
78 |
158 |
194 |
232 |
51 |
635 |
20522 |
3.09 |
2009-15 |
75 |
92 |
135 |
152 |
23 |
402 |
20738 |
1.94 |
2009-16 |
81 |
116 |
188 |
163 |
28 |
495 |
21228 |
2.33 |
2009-17 |
69 |
229 |
554 |
342 |
44 |
1169 |
24392 |
4.79 |
2009-18 |
54 |
145 |
320 |
183 |
30 |
678 |
19683 |
3.44 |
National Influenza Activity Map
The current U.S. flu weekly report 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.
--> For more information on flu surveillance activities in the State of Texas, please visit our main surveillance page.
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