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The San Bernardino County West Nile Virus Aerial Surveillance Collaboration

State: CA Type: Neither Year: 2015

BRIEF DESCRIPTION OF LHDSan Bernardino County is the largest county in the contiguous United States, covering over 20,000 square miles and including 24 cities. It is located in southeastern California, with Nevada and Arizona to the east, Orange and Riverside Counties to the south, Kern and Los Angeles Counties to the west, and Inyo and Tulare Counties to the north. With a population of almost 2.08 million, San Bernardino County is the fifth-most populous county in California and the twelfth-most populous county in the United States. PUBLIC HEALTH ISSUEThe Department of Public Health, Division of Environmental Health Services (DEHS) Mosquito and Vector Control Program (MVCP) is dedicated to improving the quality of life, reducing and preventing potential public health risks, and ensuring public health and safety for all residents and visitors of San Bernardino County. In 2012, mosquito-transmitted West Nile virus (WNV) was reported at record-breaking highs with over 5,000 human cases nationwide. California reported the second-highest number of any state with 479 human cases, 20 of which were fatalities. Thirty-three of those cases occurred in San Bernardino County. During 2012, more than 18,000 homes had been foreclosed, leaving many unmaintained swimming pools. These stagnant water sources are ideal breeding locations for mosquitoes, specifically of the genus Culex, which are WNV vectors. Unmaintained pools in residential areas are difficult to locate because they are concealed in back yards and are not easily visible. Typically, MVCP becomes aware of these potential breeding sites only after a complaint is received from a neighbor or local resident. Relying solely on complaints leaves residential areas susceptible to heavy mosquito populations, and increases the risk of WNV exposure. From 2011 to 2012, the incidence of WNV in California increased by 67%, and nationally by 87%. This startling rise prompted MVCP to evaluate current mosquito surveillance methods and devise a plan to address the factors that contributed to the WNV epidemic. These evaluations lead to the implementation of the WNV aerial surveillance collaboration between MVCP and the San Bernardino County Sheriff’s Department Aviation Division. GOALS AND OBJECTIVES With the incidence of WNV rapidly increasing throughout the country, MVCP collaborated with the San Bernardino County Sheriff’s Department Aviation Division in utilizing aerial surveillance to identify and reduce mosquito-breeding hazards by targeting unmaintained (green) swimming pools in residential neighborhoods. IMPLEMENTATION AND ACTIVITIESDuring routine aerial patrols in the 2012 mosquito season, the Aviation Division was able to identify and locate numerous green pools within the County by using technology that provides parcel information as the aircraft flies over a residence. Addresses of the identified green pools were given to MVCP for inspection and abatement. MVCP field staff would then verify the condition, clarity, and mosquito-breeding potential for the identified pools. If mosquito-breeding was observed, MVCP issued a Notice of Violation (NOV) requiring the responsible party to eliminate the mosquito-breeding hazard. In addition, these pools were treated with a larvicide to exterminate mosquito larvae and prevent the development and spread of adult mosquitoes. Follow-up inspections were conducted at all mosquito-breeding pools to verify compliance. Pools that still presented a risk during follow-up inspections were pumped to remove all water in order to eliminate the mosquito-breeding hazard. RESULTS/OUTCOMES During the 2012 collaboration, 289 green pools were identified through aerial surveillance. By the end of that year, MVCP addressed approximately 440 unmaintained swimming pools that bred mosquitoes or were potential mosquito-breeding hazards. An unmaintained residential swimming pool measuring 15 feet by 30 feet has the potential to produce 2.25 million mosquitoes per week. With the help of the Sheriff’s Department Aviation Division, it is estimated that MVCP prevented the potential development of 990 million mosquitoes per week, greatly reducing the potential incidence of WNV. The success of this collaboration in 2012 helped San Bernardino County maintain a WNV incidence rate of 1.60 cases per 100,000 people, approximately 12% below the national incidence rate of 1.81 cases per 100,000 people. PUBLIC HEALTH IMPACT OF PRACTICEUnmaintained swimming pools have the potential to breed millions of mosquitoes in residential neighborhoods, increasing the potential risk of WNV infection. This partnership aided in the prevention of WNV, and protected the public by providing a service that decreased the amount of water sources that could have allowed mosquitoes to breed uncontrollably. Ultimately, MVCP and the Sheriff’s Department Aviation Division efficiently addressed factors that contributed to WNV, kept operational costs low, and improved public health, safety, and the quality of life for the residents and visitors within San Bernardino County. WEBSITE The San Bernardino County Department of Public Health, Division of Environmental Health Services website is www.sbcounty.gov/dph/dehs.
STATEMENT OF PUBLIC HEALTH ISSUE In 2012, the spiraling economic down-turn and high foreclosure rates caused many residential pools to become abandoned and unmaintained, consequently creating ideal breeding conditions for West Nile virus (WNV) transmitting mosquitoes. These challenging circumstances contributed to the largest WNV outbreak since 2003, with national record-breaking highs of over 5,000 human cases. With the incidence of WNV rapidly increasing throughout the country, the San Bernardino County Mosquito and Vector Control Program (MVCP) collaborated with the San Bernardino County Sheriff’s Department Aviation Division in utilizing aerial surveillance to identify and reduce mosquito-breeding hazards by targeting unmaintained (green) swimming pools in residential neighborhoods. This collaboration allowed MVCP to efficiently inspect, treat, and abate the mosquito-breeding hazards in previously unknown locations, thus greatly reducing the potential incidence of WNV. TARGET POPULATION Everyone is potentially susceptible by WNV, and the odds of exposure increase for those who live near stagnant bodies of water that are breeding mosquitoes. Many residential properties, whether occupied or vacant, have mosquito-breeding sources, such as unmaintained swimming pools. The population size that was targeted was limited to the prescheduled flight routes of the San Bernardino County Sheriff’s Department Aviation Division and those areas within the sphere of influence of the MVCP. The cities and unincorporated areas within MVCP’s sphere of influence are Upland, Fontana, Rialto, Bloomington, Grand Terrace, San Bernardino, Loma Linda, Redlands, Mentone, Highland, and Yucaipa. This is the most densely populated area served by MVCP and is estimated to have a population of approximately 833,939 people. This does not take into account the visitors traveling within this area. The actual target population size can be significantly higher, especially in the summer months when outdoor activities increase. PAST METHOD TO PROBLEM WNV was introduced to the United States in 1999 and made its way to California in 2003. Since then, MVCP and the Sheriff’s Department Aviation Division had been collaborating in an effort to reduce mosquito-breeding hazards by identifying green pools from the air. However, technology was limited and the budget minimal. At that time, specified surveillance days were arranged for by MVCP field staff to accompany the pilots in the helicopter. From the air, street signs and addresses cannot be seen, and MVCP field staff that were familiar with the targeted neighborhoods would attempt to identify the properties with green pools and then place them on photocopied maps. Identifying the correct property with the green pool proved to be extremely challenging and time consuming. Properties near major streets or freeways were easier to locate than those in residential areas where landmarks are few and all of the streets looked the same. Additionally, when the Aviation Division was sent on an urgent call, the surveillance activity stopped. For the most part, the MVCP field staff would spend an entire day in the air, and hoped they had accurately located the potential green pools on their map. The time needed in the office to confirm the locations on the map would often delay responding to the property, frustrating efforts to control mosquito development in a timely manner. With that information, MVCP field staff would go out to verify the condition, clarity and mosquito-breeding potential for the identified pool, if that property actually had a pool. On many occasions, the properties that MVCP field staff visited were not the properties that were identified from the air, and additional time was needed to locate the correct addresses. This method of collaboration took staff from both agencies away from their regular work duties, sometimes wasting valuable time that was intended to promptly control mosquito-breeding and resulting in the identification of a minimal number of pools. THE CURRENT PRACTICE IS BETTER During routine aerial patrols in the 2012 mosquito season, the Aviation Division was able to identify and locate numerous green pools within the county by using new technology that provides parcel information as the aircraft flies over a residence. Lists of addresses for the identified green pools were given to MVCP for inspection and abatement. The MVCP field staff would then go out, typically within 48 hours of receiving the information, to verify the condition, clarity, and mosquito-breeding potential for the identified pools. If mosquito-breeding was verified during an inspection, MVCP issued a Notice of Violation (NOV) requiring the responsible party to eliminate the mosquito-breeding hazard. In addition, these pools were immediately treated with a larvicide to exterminate the live mosquito larvae and prevent the development and spread of adult mosquitoes. Follow-up inspections were conducted on all mosquito-breeding pools to verify compliance. If pools still presented a risk during follow-up inspections, MVCP staff pumped them to remove all water in order to eliminate the mosquito-breeding hazard. INNOVATIVE PRACTICE The current practice is an innovative and creative use of existing practices. Being government agencies, both the Aviation Division and MVCP must take into consideration cost and fiscal accountability as major components of any new program, especially in tough economic times when government agencies are asked to do more with less. Many vector control agencies hire private helicopters or aerial photography companies to conduct their surveillance activities. With a limited budget, MVCP reached out to the Sheriff’s Department Aviation Division for assistance. The Aviation Division conducts these surveillance activities during their prescheduled routine aerial flights and routine WNV surveillance activities were already budgeted for the MVCP. Since employee time and operating expenses for both agencies were already budgeted, no additional cost was incurred.  IS CURRENT PRACTICE EVIDENCE-BASED? N/A
GOALS AND OBJECTIVES With the prevalence of West Nile virus (WNV) rapidly increasing throughout the country, the San Bernardino County Mosquito and Vector Control Program (MVCP) collaborated with the San Bernardino County Sheriff’s Department Aviation Division in utilizing aerial surveillance to identify and reduce mosquito-breeding hazards by targeting unmaintained (green) swimming pools in residential neighborhoods. STEPS TAKEN TO IMPLEMENT THE PROGRAM The Aviation Division was able to identify and locate numerous green pools within the county, during routine aerial patrols in 2012, by using technology that provides parcel information as the aircraft flies over a residence. Lists of addresses for the identified green pools were given to MVCP for inspection and abatement. The MVCP field staff would then go out, typically within 48 hours of receiving the information, to verify the condition, clarity and mosquito-breeding potential for the identified pools. If mosquito-breeding was verified during an inspection, MVCP issued a Notice of Violation (NOV) requiring the responsible party to eliminate the mosquito-breeding hazard. In addition, these pools were immediately treated with a larvicide to exterminate the live mosquito larvae and prevent the development and spread of adult mosquitoes. Follow-up inspections were conducted on all mosquito-breeding pools to verify compliance. If pools still presented a risk during follow-up inspections, MVCP staff pumped them to remove all water in order to eliminate the mosquito-breeding hazard. There was no specific criterion in selecting neighborhoods that were surveyed by the Aviation Division. The Aviation Division conducts prescheduled flight in various areas, which MVCP has no control over. These surveyed areas are also limited to the sphere of influence of the MVCP, since there are other jurisdictions that address vector control concerns within the County of San Bernardino. CRITERIA FOR AREAS SELECTED TO RECEIVE THE PRACTICE The areas selected to receive the practice were limited to the areas within the sphere of influence of the MVCP, and the prescheduled flight routes of the San Bernardino County Sheriff’s Department Aviation Division. The cities and unincorporated areas within MVCP’s sphere of influence are Upland, Fontana, Rialto, Bloomington, Grand Terrace, San Bernardino, Loma Linda, Redlands, Mentone, Highland, and Yucaipa. This is the most densely populated area served by MVCP and is estimated to have a population of approximately 833,939 people. This does not take into account the visitors traveling within this area. The actual target population size can be significantly higher, especially in the summer months when outdoor activities increase. TIMEFRAME MVCP conducts WNV surveillance activities year-round; however there is a higher risk of transmission during the summer months. The Sheriff’s Department Aviation Division conducts aerial surveillance during their prescheduled routine aerial flights during the months of June - September. This efficient and cost effective-collaboration has consistently continued since 2012. STAKEHOLDERS The Sheriff’s Department Aviation Division is a major stakeholder in this collaboration. The leaders of both the Aviation Division and MVCP met on various occasions to establish the parameters of the collaboration and maintain an open channel of communication. Maintaining communication and a professional rapport has allowed this collaboration to exceed previous attempts to identify and abate green swimming pools in residential neighborhoods. Other stakeholders from the community that have recently assisted in this aerial surveillance collaboration include the City of Redlands Police Department and the West Valley Mosquito and Vector Control District. MVCP effectively engages with community stakeholders, ensuring vector control services are provided to the residents. These community stakeholders include the cities MVCP contracts with such as Upland, Fontana, Rialto, Grand Terrace, San Bernardino, Loma Linda, Redlands, Highland, and Yucaipa. These cities allow MVCP to conduct mosquito surveillance activities within their boundaries and sphere of influence, including green pool complaints that are referred to MVCP by the Aviation Division through aerial surveillance. START-UP OR IN-KIND COSTS AND FUNDING MVCP is funded through an annual benefit assessment on approximately 700,000 properties, service contracts, and annual permit fees for inspection services. Routine WNV surveillance activities are budgeted each year, with approximately 120 person-hours of MVCP staff time spent investigating and following up on the possible mosquito-breeding sources referred by the Aviation Division. MVCP values this time at $11,340.00 (salary and benefits). During prescheduled routine flight patrols, the Aviation Division uses a helicopter, fuel, a camera, and specialized computer software. The maintenance and use of this equipment, and the Aviation Deputies’ salary and wages are estimated at about $1,700.00 per hour. Since employee time and operating expenses for both agencies were already budgeted, no additional cost was incurred.  
RESULTS AND ACHIEVEMENT OF OBJECTIVES With the prevalence of West Nile virus (WNV) rapidly increasing throughout the country, the San Bernardino County Mosquito and Vector Control Program (MVCP) collaborated with the San Bernardino County Sheriff’s Department Aviation Division in utilizing aerial surveillance to identify and reduce mosquito-breeding hazards by targeting unmaintained (green) swimming pools in residential neighborhoods. In 2012, this collaboration led to the identification of 289 green pools through aerial surveillance. By the end of that year, MVCP addressed approximately 440 unmaintained swimming pools that were breeding mosquitoes or had the potential to become a mosquito-breeding hazard. This makes up 66% of all green pool complaints received by MVCP that year. Just one unmaintained residential 15 feet by 30 feet swimming pool has the potential to produce 2.25 million mosquitoes per week. With the help of the Sheriff’s Department Aviation Division, it is estimated that MVCP prevented the potential development of 990 million mosquitoes per week, thus greatly reducing the potential incidence of WNV. The success of the collaborative effort in 2012 helped San Bernardino County maintain a WNV incidence rate of 1.60 cases per 100,000 people, which is approximately 12% below the national incidence rate of 1.81 cases per 100,000 people. The strong collaborative effort that began in 2012 expanded in 2013 and remains to date. MVCP continues to work with the Sheriff’s Department Aviation Division and began to form partnerships with other agencies in San Bernardino County, including the City of Redlands Police Department and the West Valley Mosquito and Vector Control District. In 2013, with the help of these partners, 195 green pools were discovered by aerial surveillance, making up 39% of all green pool complaints received by MVCP that year. By the end of 2013, 503 unmaintained swimming pools that were breeding mosquitoes or had the potential to become a mosquito-breeding hazard were inspected and/or abated by MVCP staff. The growing collaborative effort in 2013 helped San Bernardino County maintain a WNV incidence rate of 0.62 cases per 100,000 people, which is 17% below the national incidence rate of 0.75 cases per 100,000 people. EVALUATION OF PRACTICE The effectiveness of this program was viewed by comparing the number of green pools that were investigated and abated by aerial surveillance to the total number of green pool complaints investigated by MVCP. In 2012, 66% more unmaintained swimming pools were addressed by MVCP as a result of this collaboration than would have been addressed without their assistance. Success was also achieved when comparing the WNV incidence rate of San Bernardino County to that of the national incidence rate. This demonstrates that the efforts of this aerial surveillance collaboration contributed to maintaining an incidence rate lower than the national incidence rate. No modifications, at this time, have been made to the practice as a result of the data.  
LESSONS LEARNED IN RELATION TO PRACTICE AND PARTNER COLLABORATION Since 2012, the West Nile virus (WNV) aerial surveillance collaboration between the San Bernardino County Mosquito and Vector Control Program (MVCP) and the Sheriff’s Department Aviation Division has contributed to the identification of unmaintained (green) swimming pools, and the abatement and reduction of these potential mosquito-breeding hazards in San Bernardino County. The method used for this practice is simple and cost-effective. Both agencies communicate with each other as to when the surveillance will begin and end. The list of identified green pools are sent to MVCP from the Aviation Division in a timely manner, allowing MVCP field staff ample time to investigate and abate the hazard. As of now, this method has worked for both agencies, and the lines of communication remain open. COSTS Budgetary constraints were considered when collaborating with the Aviation Division. In assessing the actual cost of the collaboration, it was identified that routine WNV surveillance activities along with equipment use and maintenance were already budgeted for the year. Each agency also budgeted salary and benefits for their employees. Therefore, no additional cost was incurred by both agencies and the benefit of this collaboration decreased the potential risk to the public by reducing the number of mosquito-breeding water sources that could have spread WNV to the surrounding neighborhoods. STAKEHOLDER COMMITMENT AND SUSTAINABILITY PLANS The collaboration and communication between MVCP and the Aviation Division has allowed the practice to continue consistently since 2012. MVCP and the Sheriff’s Department Aviation Division were able to efficiently address factors contributing to WNV, keeping operational costs low, and improving public health, safety, and the quality of life for the residents and visitors within San Bernardino County. Both agencies are committed to continue the collaboration to protect the communities they serve. The communities within San Bernardino County have and will continue to benefit from this collaboration with a reduction of mosquito-breeding hazards from unmaintained green swimming pools that have the potential to breed mosquitoes and spread WNV.