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2008 Model Practice Application (Public)

Application Name: 2008 Model Practice Application (Public) : Dallas County Health and Human Services : Dallas County Health and Human Services Early Detection and Prevention of Mosquito-borne Diseases Program
Applicant Name: Mr. Zachary Thompson
Practice Title
Dallas County Health and Human Services Early Detection and Prevention of Mosquito-borne Diseases Program
Submitting LHD/Agency/Organization
Dallas County Health and Human Services

Overview

DCHHS began this system for sentinel detection and the testing of mosquito samples to protect the citizens and visitors to Dallas County from mosquito-borne diseases. Goals for this mission are to: 1) provide an early warning system for human morbidity from transmission of WNV or other mosquito-borne diseases; and 2) develop fixed sites, multi-jurisdictional surveillance network for geographic control. Measurable objectives have driven the positive changes in this program. These objectives include: 1) developing critical data baselines, such as the minimum infection rate (MIR) for all mosquito pools by Year 2 for the detection of mosquito loads and the improvement of data quality county-wide; and 2) to develop fixed surveillance sites with gravid traps in each participating municipality.
Responsiveness and Innovation
DCHHS created the Early Detection and Prevention of Mosquito-borne Diseases Program (EDP) to develop a countywide baseline for viral loads and exposure density of endemic mosquito vectors in the county, given the active history of Saint Louis Encephalitis and West Nile Virus. An epidemic of St. Louis Encephalitis in Dallas claimed many lives in 1966. The threat of mosquito-borne illness was heightened further when the West Nile Virus spread across the United States. Increasing temperatures and the shifting geographic reach of Dengue Fever in South Texas have also raised concern of whether the historical endemic areas for Dengue Fever might be changing. The need to ensure the safety and health of people living and working in Dallas was the driving force for Dallas County health officials. DCHHS officials wanted an early warning system for human cases. A scientific baseline of key mosquito vectors and their virology across the county fixed-surveillance sites was needed. DCHHS adopted enhanced mosquito surveillance techniques and testing procedures for greater precision and faster results. The continuing deep interest of the media and the public since 2002 has effectively communicated the relevancy of improved vector control. How EDP Addresses the Issue DCHHS initiated the new protocol to augment exposure measurements (viral loads) and to leverage Dallas County resources more effectively with other municipalities. DCHHS staff provides assistance with investigating, monitoring, testing, and reporting of WNV activity in Dallas County. In addition, DCHHS provides a financial incentive of $35 for the first municipal fixed site. To begin the data collection, mosquitoes are sampled from areas of historical activity early in the season. These early samples from fixed trap locations provide a baseline for WNV among mosquito populations. Early warnings to communities with known high risk factors have been dependent on the fixed system of gravid traps which attract female mosquitoes, such as the WNV carrier Cu. quinquefasciatus, to the bait infusion. The results are relayed back to municipalities for activation of control measures. Persons in Dallas are alerted via the media. Public alerts include information such as the general location of infected mosquito pools, the specific spray area, and ways for persons to reduce exposure to themselves and their families from WNV exposure. At season’s end, the results of the end-of-year meetings are posted in the final seasonal newsletter. With ongoing improvements and enhanced data, baselines are stabilizing and the predictive capacity of the model is improving to allow for a 14-day warning of the beginning of human WNV morbidity. A literature review was used to determine that the practice goes beyond existing practices and is an inventive use of existing techniques. Bradford (2005), JAMA, (2006), Kulasekera et al, (2001), and Turell (2001) discuss the need for systematic testing using molecular techniques and the calculation of minimum infection (MIR) to determine exposure density of viral activity. A distributed fixed system over time is also addressed as a way of stabilizing data and improving the quality of the data collected and providing information about transmission dynamics. The establishment of a fixed gridded, surveillance site in each jurisdiction to monitor abundance and infection derives from such studies and workshops as those by Dr William K Reisen’s 2006 Workshop on West Nile virus testing ‘the big picture’. His concept is to develop the permanent grid to provide early warning and detection of WNV and Saint Louis Encephalitis. Similarities Given the Promising and Best Model Practices listed in the NACCHO database, the main programs addressed are: 1) Dallas County, TX, 2) City of Sedwick, KS, 3) Tarrant County, TX, and, 4) City of Plano, TX. As stated earlier, Dallas County was using a Geographic Information System and a GPS unit to ensure accuracy of the locations or high risk area
Agency Community Roles
DCHHS met with individual municipalities and signed Municipal of Understandings (MOUs) with each. An initial meeting allowed all participants to develop their fixed sites and to discuss the sharing of resources. Dallas volunteered its calibration services and payment for the first fixed sites in each jurisdiction. The end of year meetings allow each municipality to see the final statistics from the current year, to see what worked, to see if there were any gaps in the program, and to decide as a group how they tweak the system for the next year. This process has encouraged municipalities to join the effort. While their vector control programs engage in more work, the other services offered enhanced the coverage for their city. DCHHS continues to provide incentives for participation and to protect the public.
Costs and Expenditures
Existing medical, epidemiological, and environmental health staff of DCHHS was utilized to create and implement a WNV and vector-borne surveillance program. DCHHS provided additional support for GIS analysis, a Public Information Officer (PIO), and laboratory analysis. Ongoing funding of equipment and supplies for the program was accomplished through the support of each contracting municipalities and DCHHS. DCHHS provided incentives for jurisdictions to participate by paying for the first fixed site cost of $35. Collaborating jurisdictions contributed their existing environmental health staff. DCHHS provided funds for two part time and one full time vector control personnel. The Dallas PIO provided weekly reports. As the program continues, additional fees may be required to assist in the support of mosquito testing costs incurred. The DCHHS general budget funded the project for the Early Detection and Prevention of Mosquito-borne Diseases Program. Other municipalities used existing vector control staff and relied on DCHHS for specialty services, such as a GIS technician and a Public Information Officer.
Implementation
This program builds on earlier vector control initiatives through the use of geographic information systems, rapid alerting of citizens by the media, vector-control personnel working with epidemiologists on early predictors of human WNV cases, strategic vector control to lessen resistance of mosquitoes, and conducting educational campaigns to Dallas residents to lessen exposure. Actionable steps for the program are: I. Goal 1, Objective 1 A. Increase Participation – timeframe: Each October – January 1. Offer financial and service incentives. 2. Show past results for base data with positive mosquito sites and human cases. 3. Show potential participants that the group decides what works and what does not. 4. Show enhanced scientific standards of the program. 5. Sign Memorandums of Understanding (MOUs). B. Assure scientific standards– timeframe: throughout year 1. Assess methodology with professional entomologists, DCHHS’ health authority, epidemiology team. 2. Ensure calibration and quality of sprayers (March through October). 3. Collect samples for mosquito identification and virology data (March through October). 4. Collect data (March through October). 5. Conduct analysis of data (throughout year). 6. Calculate statistics (throughout year). C. Review literature on Vector Control of WNV, SLE, and Dengue Fever – timeframe: throughout year II. Goal 2, Objective 2 A. Signup and Increase Participation – timeframe: throughout the year 1. Continue to assess appropriate incentives (throughout year) 2. Ensure programmatic communications about positive hot spots, fixed sites, and human cases (throughout year) 3. Negotiate fixed site locations (annual meeting or as new municipalities enroll in program) 4. Ensure delivery of weekly updates (throughout year) 5. Maintain consistency (throughout year) 6. Conduct an After Action Annual Meeting a. Review maps from season and geographic spread. b. Review calculations across municipalities. c. Re-evaluate fixed grid. d. Determine lessons learned (what worked versus what did not). e. Determine what members want. 7. Results from After Action Report (AAR) meeting posted in WNV Weekly Newsletter DCHHS in-house laboratory analyzed human samples, activated appropriate control measures, notified the public within 24 hours, provide education about the threat of WNV. The ability to have reverse transcription-polymerase chain reaction samples tested at the DCHHS laboratory with results available within 48 hours greatly enhanced the health department’s surveillance and response efforts.
Sustainability
Each jurisdiction used existing vector control personnel. Excluding major budget shortfalls each municipality is continuing participation because they save money given the joint effort, the sharing of resources, and the collection of exposure information. The commitment is ensured through the ongoing need for effective mosquito control programs and the need to understand the processes involved to eventually reduce human morbidity.
Outcome Process Evaluation
Goal 1: The Early Warning System from enhanced data quality. A series of maps were produced through the summer and fall of 2007 showing the participating 28 municipalities in Dallas County. Daily measurements began for the county-wide program on 4-18-07 with DCHHS analyzing the results. The 199th sample on 7-11-07 was the first positive trap of the 74 positive sites found during the 2007 season. An index of viral activity using the minimum infection rate (MIR) was developed for each site. For 2007, the teams collected 530 specimens from the sample sites to determine viral activity in each geographic locale. In terms of data quality, DCHHS provided calibration for all participating jurisdictions’ mosquito sprayers. Likewise, Dallas County trained each participating municipalities’ staff on global positioning systems units. The 2007 surveillance program was able to report positive mosquitoes 5 weeks before the first human case, emphasizing the importance of early detection of viral loads in each geographic locale. DCHHS had not been able to provide such an early warning system previously. This initial assessment of vector activity served as a precursor for human WNV morbidity. DCHHS will continue to assess seasonal trends to facilitate reduction of human morbidity and mortality from West Nile Virus and other mosquito-borne diseases. At the wrap-up meeting in January 2008, municipal representatives added more sites. Goal 2: Fixed sites across multijurisdictional sites. The program experienced a twofold increase in participation from 2006 to 2007. In 2006, 15 (48.4%) of 31 jurisdictions participated. Increased participation occurred by the second year of operations (90.3 % of the municipalities) with incentives including the use of GIS technician, public information officer and initial funding of fixed site expenses. The improved vector control program provided better coverage on jurisdictional boundaries and improved communication through the sharing of key viral data and weekly newsletters. At the 2007 end-of-year meeting, the jurisdiction requested notification of all members from each positive site to improve interventions along municipal boundaries. Members wanted contact information shared among everyone to assure accessibility. Each municipality representative discussed what worked and what did not. Representatives asked for the weekly newsletter and the annual after action report to be sent to all listed contacts and not just primary representatives.
Lessons Learned
Key Elements Replication