2008 - 2009 Texas Influenza Surveillance Information
Influenza Surveillance Report for MMWR Week 37
The influenza (flu) activity level for Texas for the week ending September 19, 2009 was “widespread.” For definitions of flu activity levels please see http://www.cdc.gov/flu/weekly/fluactivity.htm. During week 37, 907 (32.2%) 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 37.
Reports from Health Service Regions
Reports were received from all Health Service Regions (HSRs) for week 37. HSRs 2/3, 4/5N, 6/5S, 7, 9/10, and 11 reported an increased level of flu activity compared to week 36. HSRs 1 and 8 reported the same level of flu activity compared to week 36. For a map of Health Service Regions please visit the following website: www.dshs.state.tx.us/regions/state.shtm Laboratory Results
During week 37, eleven hospital laboratories and public health agencies across Texas reported conducting a total of 2,817 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 (69.8%) 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 37 |
No. of specimens tested |
2,817 |
No. of positive specimens (%) |
907 (32.2%) |
Positive specimens by type/subtype |
Influenza A |
906 (99.9%) |
A (novel H1N1) |
294 (32.5%) |
A (subtyping not performed) |
612 (67.5%) |
A (unable to subtype) |
0 (0%) |
A (H3) |
0 (0%) |
A (seasonal H1) |
0 (0%) |
Influenza B |
1 (0.1%) |
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, ICU admissions, and deaths began in Texas on September 20, 2009.
Antigenic Characterization
CDC has reported antigenic characterization results from 51 seasonal influenza isolates [20 influenza A (H1N1), 8 influenza A (H3N2), and 23 influenza B viruses] and 6 novel influenza A (H1N1) viruses received from the DSHS Laboratory since the beginning of the 2008–09 flu season. Other laboratories in Texas submit influenza isolates to CDC for testing, but those results were not available for this report. Influenza A (H1N1) seasonal [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 (H3N2) [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) [23]
Victoria lineage [16] - Sixteen 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.
Novel influenza A (H1N1) [6]
- All 6 viruses were characterized as A/California/07/2009-like (H1N1), the reference virus selected by the World Health Organization (WHO) as a candidate for the novel influenza A (H1N1) vaccine.
Antiviral Resistance
Since September 28, 2008, 22 seasonal influenza A (H1N1) isolates, 8 influenza A (H3N2) isolates, 23 influenza B isolates, and 5 novel influenza A (H1N1) isolates from the DSHS laboratory have been tested by CDC for antiviral resistance. Other laboratories in Texas submit influenza isolates to CDC for testing, but those results were not available for this report; therefore, the total number of novel influenza A (H1N1) isolates that have been tested from Texas by CDC is not known at this time.
Flu Types/Subtypes |
Isolates Tested (n) |
Resistant Viruses, Number (%)
|
Isolates Tested (n) |
Resistant Viruses, Number (%)
|
Oseltamivir |
Zanamivir |
Adamantanes |
Influenza A (H1N1) (seasonal) |
22 |
22 (100) |
0 (0) |
22 |
0 (0) |
Influenza A (H3N2) |
8 |
0 (0) |
0 (0) |
7 |
7 (100) |
Influenza B |
23 |
0 (0) |
0 (0) |
N/A* |
N/A* |
Influenza A (H1N1) (novel)** |
Not available |
2 (--) |
0 (0) |
Not available |
-- (100) |
*Adamantanes are not effective against influenza B viruses.
**Antiviral resistance testing is performed on a subset of Texas isolates at the CDC lab. The total number of novel influenza A (H1N1) isolates from Texas that have been tested for antiviral resistance is not available. Of all of the novel influenza A (H1N1) isolates from Texas that have been tested for antiviral resistance, only 2 have shown resistance to oseltamivir. No novel influenza A (H1N1) isolates have shown resistance to zanamivir. All novel influenza A (H1N1) isolates have shown resistance to the adamantanes.
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
Three influenza-associated pediatric deaths occurred during week 37. All three children had confirmed novel influenza A (H1N1) by PCR testing. The first death occurred in an 11-year-old resident of HSR 2/3. The child had no underlying medical conditions; however, the child's blood culture was positive for methicillin-sensitive Staphylococcus aureus (MSSA) during the influenza illness. The second death occurred in a 3-year-old resident of HSR 2/3 with multiple significant underlying medical conditions. The third death occurred in a 25-day-old resident of HSR 6/5S with a significant underlying medical condition. Texas has reported 18 influenza-associated pediatric fatalities during the 2008-09 influenza season. School Closures and Institutional Outbreaks
An outbreak of influenza A [including one test positive for novel influenza A (H1N1)] was reported at a university in Kleberg County during week 37. DSHS has issued guidance for cases of ILI and novel influenza A H1N1 in summer camps, schools, and congregate facilities. Please see http://www.texasflu.org for more information. U.S. Outpatient Influenza-like Illness Surveillance Network
Thirty-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 37. Of these 34 providers, 27 (79%) saw at least one patient with ILI. Of all patient visits during this week, 7.80% were due to ILI. The percentage of visits due to ILI for week 37 was higher than that of the peak week (week 6, week ending February 14, 2009) during the 'official' 2008-2009 influenza season. The ILI baseline for HHS Region 6 (Arkansas, Louisiana, New Mexico, Oklahoma, and Texas) of the United States is 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 9/25/2009 10:41:58 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 |
80 |
120 |
152 |
106 |
20 |
398 |
19857 |
2.00 |
2008-44 |
82 |
136 |
199 |
104 |
26 |
465 |
20972 |
2.22 |
2008-45 |
79 |
110 |
111 |
122 |
27 |
370 |
20959 |
1.77 |
2008-46 |
74 |
110 |
107 |
103 |
23 |
343 |
19890 |
1.72 |
2008-47 |
76 |
137 |
143 |
122 |
19 |
421 |
19907 |
2.11 |
2008-48 |
80 |
132 |
132 |
125 |
37 |
426 |
17012 |
2.50 |
2008-49 |
78 |
143 |
159 |
153 |
24 |
479 |
20446 |
2.34 |
2008-50 |
76 |
133 |
146 |
108 |
28 |
415 |
19450 |
2.13 |
2008-51 |
70 |
172 |
177 |
175 |
24 |
548 |
17663 |
3.10 |
2008-52 |
77 |
194 |
153 |
154 |
34 |
535 |
13509 |
3.96 |
2008-53 |
78 |
176 |
141 |
165 |
46 |
528 |
15329 |
3.44 |
2009-01 |
79 |
162 |
182 |
188 |
38 |
570 |
18646 |
3.06 |
2009-02 |
78 |
178 |
287 |
235 |
41 |
741 |
20222 |
3.66 |
2009-03 |
79 |
174 |
468 |
341 |
43 |
1026 |
23058 |
4.45 |
2009-04 |
79 |
260 |
679 |
333 |
47 |
1319 |
24350 |
5.42 |
2009-05 |
74 |
282 |
884 |
467 |
40 |
1673 |
24734 |
6.76 |
2009-06 |
80 |
301 |
965 |
392 |
59 |
1717 |
24320 |
7.06 |
2009-07 |
79 |
317 |
803 |
316 |
57 |
1493 |
25821 |
5.78 |
2009-08 |
74 |
221 |
552 |
283 |
57 |
1113 |
24664 |
4.51 |
2009-09 |
77 |
194 |
423 |
245 |
71 |
933 |
22428 |
4.16 |
2009-10 |
80 |
221 |
325 |
212 |
77 |
835 |
22635 |
3.69 |
2009-11 |
77 |
167 |
269 |
178 |
58 |
672 |
19656 |
3.42 |
2009-12 |
72 |
109 |
150 |
179 |
18 |
456 |
20910 |
2.18 |
2009-13 |
74 |
115 |
143 |
163 |
16 |
437 |
18760 |
2.33 |
2009-14 |
81 |
158 |
199 |
234 |
51 |
642 |
20963 |
3.06 |
2009-15 |
78 |
92 |
138 |
156 |
23 |
400 |
21254 |
1.92 |
2009-16 |
87 |
133 |
200 |
163 |
28 |
524 |
22058 |
2.38 |
2009-17 |
77 |
260 |
570 |
348 |
44 |
1222 |
25406 |
4.81 |
2009-18 |
72 |
200 |
361 |
185 |
31 |
777 |
22503 |
3.45 |
2009-19 |
65 |
125 |
253 |
183 |
24 |
585 |
19066 |
3.07 |
2009-20 |
63 |
122 |
255 |
134 |
7 |
518 |
19150 |
2.70 |
2009-21 |
64 |
115 |
221 |
111 |
31 |
478 |
17728 |
2.70 |
2009-22 |
61 |
108 |
188 |
88 |
14 |
398 |
18573 |
2.14 |
2009-23 |
55 |
79 |
103 |
29 |
9 |
220 |
10111 |
2.18 |
2009-24 |
53 |
65 |
119 |
79 |
4 |
267 |
16773 |
1.59 |
2009-25 |
59 |
72 |
114 |
79 |
15 |
280 |
16624 |
1.68 |
2009-26 |
59 |
68 |
105 |
75 |
13 |
261 |
15326 |
1.70 |
2009-27 |
58 |
72 |
90 |
72 |
15 |
249 |
16643 |
1.50 |
2009-28 |
62 |
44 |
101 |
78 |
15 |
238 |
17296 |
1.38 |
2009-29 |
60 |
67 |
101 |
73 |
14 |
255 |
16844 |
1.51 |
2009-30 |
55 |
25 |
41 |
23 |
11 |
100 |
9965 |
1.00 |
2009-31 |
60 |
56 |
92 |
95 |
9 |
252 |
17727 |
1.42 |
2009-32 |
56 |
56 |
109 |
81 |
9 |
255 |
17385 |
1.47 |
2009-33 |
53 |
46 |
110 |
124 |
13 |
293 |
18887 |
1.55 |
2009-34 |
52 |
74 |
267 |
99 |
3 |
443 |
19040 |
2.33 |
2009-35 |
46 |
117 |
418 |
88 |
6 |
629 |
19522 |
3.22 |
2009-36 |
42 |
117 |
592 |
155 |
10 |
874 |
18939 |
4.61 |
2009-37 |
34 |
219 |
1005 |
284 |
16 |
1524 |
19547 |
7.80 |
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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