Dallas County Health and Human Services Arbovirus Surveillance Report Week 35 ending September 3, 2016

Transcription

1 Dallas County Health and Human Services Arbovirus Surveillance Report Week 35 ending September 3, 16 In week 34, 27 mosquito traps tested positive for WNV. In week 35 to date, 23 mosquito traps have tested positive for WNV in zip codes: 7538, 7539, 7543, 7544, 7551, 7552, 7563, 7563, 758, 7581, 7582, 7598, 75115, 75134, 75137, 75159, 754, 75211, Thirty seven human WNV cases, including 24 patients with neuroinvasive disease have been reported. To date, 746 Dallas County residents have been tested for Zika infection. Thirty two travel-associated confirmed cases of Zika infection have been identified in Dallas. An additional 18 pregnant women with laboratory criteria for possible Zika infection have been reported to CDC for US Zika Pregnancy Registry surveillance, 4 of whom had symptoms. m Aedes albopictus and Aedes aegypti continue to circulate in the area. Table 1. Mosquito Laboratory and Human Case Surveillance Data for WNV, Dallas County Week Ending 7/23 7/3 8/6 8/13 8/ 8/27 9/3 YTD MMWR Week * 35* Total Placed in Dallas County a ,653 Number of Positive Mosquito (PHL; IL) c 41; 3 52; 3 51 ; 5 3; 1 35; 2 22; 5 ; 3 48; 47 Number of Pools Tested (PHL; IL) b,c 9; ; 3 214; ; ; ; ; 29 4,117; 495 Number of Trap Results Currently Pending Average Number of Cx. quinquefasciatus per Trap d Total Number of Cx. quinquefasciatus Trapped and Tested 4,617 6,191 4,763 4,56 4,444 3,515 5, ,232 Number of Positive Mosquito Pools (PHL; IL) c 43; 3 56; 3 53; 5 31; 1 35; 2 22; 5 ; 3 511; 47 WNV Infection Rate per 1, Cx. quinquefasciatus e Weekly Vector Index (VI) f Presumptive WNV Viremic Blood Donors WNV Human Cases (WNND; WNF) g 1; 6 4; 1 3; 1 1; 4; 4 6; 3; 1 24; 13 Table 2. Mosquito Laboratory and Human Case Surveillance Data for Chikungunya, Dengue and Zika Virus, Dallas County Week Ending 7/23 7/3 8/6 8/13 8/ 8/27 9/3 YTD MMWR Week * 35* Total Biogents Sentinel- Placed in Dallas County h Average Number of Aedes per Trap i Chikungunya Human Cases (Confirmed & Probable) j 2 Dengue Human Cases (Confirmed & Probable) k Zika Human Cases (Confirmed Only) l Pregnant Women with Possible Zika Infection m One mosquito trap containing only Aedes albopictus was positive for WNV, and is not included in VI calculations. *Data for most recent 2 weeks are preliminary, and reflect results reported as of 1:3 a.m. September 6, 16. a. All traps deployed in municipalities submitting data to DCHHS since Week 13. Includes traps without mosquitoes, malfunctioning traps and traps with pending results b. Excludes traps without female Culex quinquefasciatus identified. Maximum of 5 female Culex quinquefasciatus per pool; more than 1 pool may be tested per trap c. PHL = Public health laboratory (DSHS, DCHHS) testing performed by viral culture or CDC RT-PCR protocol; IL = Testing from independent labs by alternate methods d. Average abundance of female Culex quinquefasciatus mosquitoes per trap night/week (excludes non-working traps) e. WNV Infection rates calculated using a Maximum Likelihood Estimation (MLE). Biggerstaff BJ. PooledInfRate, version 4.; Microsoft Excel Add-In; CDC 7 f. The Vector Index (VI) reflects the MLE adjusted for Culex quinquefasciatus abundance. VI= i=species N ip i, where N is the average number of Culex quinquefasciatus mosquitoes collected per trap night and P is the estimated infection rate g. Human cases by week of report to health department. WNND = West Nile Neuroinvasive Disease; WNF = West Nile Fever h. All Biogents (BG) Sentinel traps deployed in municipalities submitting data to DCHHS since Week 15. Includes traps without mosquitoes, malfunctioning traps i. Average abundance of Aedes albopictus and Aedes aegypti mosquitoes per night/trap in BG- (excludes non-working traps) j. Human CHKV cases by week of report to health department (AT : Autochthonous case; I : imported) k. Human Dengue cases by week of report to the health department l. Confirmed human Zika cases by week of report to health department (Excludes any pregnant cases) m. Possible Zika Virus Infection Among Pregnant Women United States and Territories, May 16,

2 Table 3. WNV Positive Gravid Mosquito by City, Dallas County* Week Ending 7/23 7/3 8/6 8/13 8/ 8/27 9/3 YTD MMWR Week * 35* # Human WNV Cases Range Total # of /Week 1 Addison Pending 9 Balch Springs Carrollton Pending 3 Cedar Hill Cockrell Hill Coppell Pending 23 Dallas DeSoto Duncanville Farmers Branch Pending 11 Garland Grand Prairie Highland Park Hutchins Irving Lancaster Mesquite Richardson Rowlett Sachse Seagoville Sunnyvale 2 2 Unincorporated County University Park Wilmer Total *Data for most recent 2 weeks are preliminary, and reflect results reported as of 1:3 a.m. September 6, 15. Pending indicates that no results for any traps have yet been received. 1 Range of numbers of traps placed weekly, in weeks Figure 1: All WNV Negative and Positive Mosquito Collected During 16: Weeks 13-35* (N=4,653) Figure 2: Cumulative WNV Positive Mosquito Collected: Weeks 13-35* (N=527) Positive Negative Pending *Data for most recent 2 weeks are preliminary DCHHS Epidemiology (214) Epidemiology@dallascounty.org

3 Average Abundance Cx. quinquefasciatus Figure 3: WNV Positive Mosquito Collected During 16: Weeks 34 and 35* (N=5) Figure 4: Trap Counts of Female Cx. quinquefasciatus from 16 Season: Weeks 13-35* Positive < 1 Mosquitoes/Trap Mosquitoes/Trap 5-1 Mosquitoes/Trap >1 Mosquitoes/Trap Figure 5: Average Numbers of Female Cx. quinquefasciatus per Trap-night and WNV Vector Index by Week: 12 Season and 16 Season (through Week 35*) 1 1 *Figure 4 only shows traps for which results were available; malfunctioning traps were excluded. Almost all traps are at fixed sites. Note: Most recent 1-2 weeks data are preliminary and subject to change following receipt of data still pending. Average Abundance 16 Average Abundance VI 12 VI **.4 Vector Index Collection Date by MMWR Week. ** Vector Index of.5 is the historical threshold associated with larger local epidemics of WNV illnesses in humans. Note: Most recent 1-2 weeks data are preliminary and subject to change following receipt of data still pending. *Data for most recent 2 weeks are preliminary DCHHS Epidemiology (214) Epidemiology@dallascounty.org

4 Average Abundance Cx. quinquefasciatus Vector Index (VI) Figure 6: WNV Vector Index by Week: Seasons The Vector Index (VI) reflects the MLE adjusted for Culex quinquefasciatus abundance. VI= i=species N ip i, where N is the average number of Culex quinquefasciatus mosquitoes collected per trap night and P is the estimated infection rate MMWR Week - Year Figure 7: Average Numbers of Female Cx. quinquefasciatus per Trap-night by Week: Seasons MMWR Week - Year DCHHS Epidemiology (214) Epidemiology@dallascounty.org

5 Number of Human WNV Cases MLE (WNV Infection Rate per 1, Cx. quinquefasciatus) 6 Figure 8: MLE (WNV Infection Rate per 1, Cx. quinquefasciatus) by Week: Seasons MMWR Week - Year Figure 9: WNV Vector Index, Viremic Blood Donors, and Human WNV Cases by Week of Report: 12 Season Human WNV Cases Viremic Blood Donors by Date of Report Vector Index *. Vector Index /5 5/12 5/19 5/26 6/2 6/9 6/16 6/23 6/3 7/7 7/14 7/21 7/28 8/4 8/11 8/18 8/25 9/1 9/8 9/15 9/22 9/29 1/6 1/13 1/ 1/27 11/3 11/1 11/17 11/24 12/1 12/8 MMWR Week - Week Ending. DCHHS Epidemiology (214) Epidemiology@dallascounty.org

6 Average Abundance of Aedes aegypti Average Abundance of Aedes albopictus Table 4: Travel-Associated Zika Infections by Country/Territories: 16 Season, Dallas County Country/Territories # Human Zika Cases (%) Mexico 8 (25.) Jamaica 4 (12.5) Guatemala 4 (12.5) Honduras 3 (9.4) Puerto Rico 3 (9.4) El Salvodor 2 (6.3) Dominican Republic 2 (6.3) Belize 1 (3.1) Virgin Islands 1 (3.1) Colombia 1 (3.1) Venezuela 1 (3.1) Nicaragua 1 (3.1) Trinidad 1 (3.1) Total 32 Figure 1: BG-Sentinel Trap Counts of Female Aedes aegypti and Aedes albopictus During 16: Weeks 15 through 35 Mosquitoes/Trap <1 Mosquitoes/Trap 1-3 Mosquitoes/Trap >3 Mosquitoes/Trap Figure 11: Average Numbers of Aedes aegypti per Trap-night: 15 and 16 Seasons* Figure 12: Average Numbers of Aedes albopictus per Trap-night: 15 and 16 Seasons* * April June Aug Oct Collection Date by MMWR Week April June Aug Oct Collection Date by MMWR Week *Aedes BG-Sentinel trapping began Week 22 in 15 DCHHS Epidemiology (214) Epidemiology@dallascounty.org

7 1/1/16 1/8/16 1/15/16 1/22/16 1/29/16 2/5/16 2/12/16 2/19/16 2/26/16 3/4/16 3/11/16 3/18/16 3/25/16 4/1/16 4/8/16 4/15/16 4/22/16 4/29/16 5/6/16 5/13/16 5//16 5/27/16 6/3/16 6/1/16 6/17/16 6/24/16 7/1/16 7/8/16 7/15/16 7/22/16 7/29/16 8/5/16 8/12/16 8/19/16 8/26/16 9/2/16 Number of Rash Reports Figure 13: Syndromic Surveillance of Emergency Department Visits for Chief Complaints of Rash, Dallas County: January 1, 16 September 3, 16 1, 8 6 Data alert Data warning Data normal Data source: 18 emergency departments in Dallas County hospitals participating in the Electronic Surveillance System for the Early Notification Of Community-based Epidemics (ESSENCE) voluntarily reporting the numbers of persons presenting with self-reported chief complaints of rash. DCHHS Epidemiology (214) Epidemiology@dallascounty.org