Department of Public Health
Invasive Surveillance Techniques
San Bernardino County is the largest county in the contiguous United States. The county covers over 20,000 square miles of land. San Bernardino County is located in southeastern California, with Inyo and Tulare Counties to the north, Kern and Los Angeles Counties to the west, and Orange and Riverside Counties to the south. San Bernardino County is bordered on the east by the states of Nevada and Arizona.
San Bernardino County has the fifth largest population in California. In July 2013, San Bernardino County's population was estimated at over two million (2,088,371). San Bernardino County is the twelfth most populous county in the nation, with more residents than 15 of the country's states, including Idaho, West Virginia, and New Mexico
Public Health Issue
In 2016, the first travel related and locally transmitted Zika cases in the continental United States occurred in the Miami-Dade County in Florida. This caused the governor of that state to declare a state of emergency. The emerging threat of travel related and locally transmitted Zika cases in the United States presents a challenge to local Vector Districts. In order to implement programs targeting this threat, every program must first determine if a threat exists in an area and up to what degree. Most people infected with Zika are asymptomatic and do not have any permanent effects from this disease. However, a pregnant woman can pass Zika to her developing fetus and cause serious birth defects, including microcephaly, even when she is asymptomatic. Zika is transmitted by the bite of an infected Aedes aegypti or albopictus mosquito. To determine the presence of these invasive non-native to California mosquitoes, each district must first identify the presence of these species of mosquitoes by using traps that have proven to be successful in other states.
In 2015, SBCMVCP trapped two Aedes albopictus mosquitoes in two different cities within its district, but was not able to replicate the results. In 2016, there were a total of 68 Aedes aegypti mosquitoes trapped, the majority from the city of Colton. All of these mosquitoes were tested for Zika and had negative results. These findings allowed the SBCMVCP to implement procedures specifically targeting the abatement of this type of mosquitoes by utilizing existing resources. However, the low amount of mosquitoes trapped, compared to the square mileage SBCMVCP serves (19,493 square miles) were not sufficient to declare a threat to the area. This kept SBCMVCP from requesting extra resources needed for a more intensive Aedes program than what had already been implemented. The SBCMVCP team believed Aedes mosquitoes were present throughout the district area, but was not able to prove this with such low number of identified Aedes mosquitoes.
Goals and Objectives
The goals and objectives of this current practice are to be able to trap existing Aedes mosquitoes in the area in order to determine the level of threat in our jurisdiction and secure funding in order to develop a more intensive program to address the threat.
The SBCMVCP developed and implemented on March 2017, a practice of setting traps in clusters. This method was based on the fact that an Aedes mosquito travels no more than 500 meters in its lifetime. Whenever a potential water source for Aedes was identified, a set of six Carbon Dioxide (CO2) traps were set within a distance of 250 feet from each other to simulate a higher density of CO2 to attract mosquitoes in the vicinity of the traps. Prior to the implementation of this practice, SBCMVCP was setting traps the way it was recommended for the Culex species of mosquitoes, which can fly up to 20 miles for a blood meal.
As of November 21, 2017, a total of 1,170 Aedes mosquitoes have been trapped in 7 cities within the service area. All of these mosquitoes have been tested and none of the results were positive for Zika. Even though the threat for a locally transmitted Zika case is low, SBCMCP has been able to prove the existence of these mosquitoes in the communities it serves and the severity of the issue. Besides being able to determine the invasive Aedes mosquitoes are present in our area, these outcomes have provided an opportunity for SBCMVCP to demonstrate the need for extra resources to develop and implement a more intensive program specifically targeting Aedes mosquitoes.
Public Health Impact
The outcome from this practice has allowed SBCMVCP to identify specific areas where the mosquitoes are established and are targeted by most of our community outreach activities, such as door to door surveys, backyards inspections, community events, distribution of flyers, and meetings with city leadership.
Website for Program
Statement of the Problem/Public Health Issue
In order to develop a program targeting Aedes mosquitoes (aegypti and albopictus) which may carry Zika, SBCMVCP had to first show the existence of the mosquitoes in its program area, areas where the threat of Zika may exist and the severity of the threat. SBCMVCP had not been successful at trapping enough Aedes mosquitoes to demonstrate the threat by using the existing trapping practices.
Target Population affected and Population Reached
San Bernardino County is racially and ethnically diverse. Half (50%) of San Bernardino County residents are Latino. Among the remaining non-Latino residents, 32% are White, 8% are Black or African American, 7% are Asian or Pacific Islander, and 3% report two or more races. Less than one percent of residents are American Indian/Alaska Native (0.6%). SBCMVCP provides quality and responsive services to County residents within its jurisdiction covering an area of 19,493 square miles with a population of over 1 million residents. By determining which areas were more at risk by having an established population of mosquitoes, SBCMVCP was able to determine which areas/cities should be focused on for community outreach and education. As of November 2nd, over 2,500 homes have been inspected and approximately 5,585 hours have been spent in mosquito related surveillance for 2017.
In the past, SBCMVCP was setting traps for Aedes mosquitoes using the same procedures as for trapping other mosquito species. The flying and feeding patterns, breeding sites, and water sources for Aedes mosquitoes are completely different than any other mosquito species.
Why is the Current/Proposed Practice Better?
The current trap setting practice takes into consideration the flying and feeding patterns, breeding site preferences and type of water sources specifically identified for Aedes mosquitoes. By setting the traps in a cluster pattern, the mosquitoes are attracted to them as they simulate a higher density of CO2.
Is the Current Practice Innovative?
The current cluster trapping is innovative as it has not been utilized by other Vector programs. Other neighboring districts, with who we have discussed trapping practices, are still utilizing other traps which have not proven to be as successful at trapping Aedes mosquitoes and are still using the same procedure used to trap other species of mosquitoes. Through the development and implementation of this practice, the existence and scope of threat to the safety or the communities we serve have been identified and recorded. This practice has also provided SBCMVCP staff a better understanding of Aedes mosquitoes. This has allowed program staff to provide abatement and community education specifically for Aedes in order to protect public health from this emerging threat.
Protecting Public Health
Zika virus has the potential to spread across warmer and wetter parts of the Western Hemisphere, including California. Zika is not a newly discovered virus but it had been limited to Africa and Southeast Asia but it arrived in South America (Brazil) in 2015 and has since then spread through Central America, the Caribbean, US Virgin Island and the contiguous United States. In adults it has been reported that, in addition to the known minor symptoms, it may cause a neurologic condition known as Guillain-Barre Syndrome (GBS). In GBS there is muscle weakness, and possible paralysis or permanent damage. Most people recover, but in rare cases it may lead to death. The highest risk is for pregnant women and their developing fetus. The effect upon the fetus seems to be significant and may cause microcephaly â€“ a birth defect, early miscarriages and stillbirths. Locally transmitted cases by infected mosquitoes have been identified in Florida and Texas. The abundance of mosquitoes continue to increase throughout the state of California. Local vector districts/programs must develop and implement abatement and response programs to address this threat.
Goals and Objectives of Practice
The County of San Bernardino Department of Public Health Division of Environmental Health Services (DEHS) is dedicated to improving the quality of life for all residents and visitors by protecting public health, promoting safety and preventing environmental hazards. SBCMVCP is the program designated to enforce the Health and Safety Code 2000 et seq and San Bernardino County Code 33.0941 et seq regarding vector control. SBCMVCP's goals and objectives are continuously being evaluated in to order to ensure the best practices are being utilized in our daily operations and surveillance. Public health and safety are always our first priority and we strive at providing the best services for the communities we serve.
Steps Taken at Implementing the Practice
Mosquito-borne diseases are the most significant public health risks globally. Population growth, increased number of individuals traveling around the world, and urbanization have increased the risks of mosquito-borne diseases to be transmitted globally. Aedes mosquitoes are an efficient vector, transmitting diseases as it bites frequently and thriving in close proximity to humans. A female adult Aedes mosquito prefers to lay eggs in small sources of stagnant water such as:
Artificial or natural water-filled containers that are within or around a home
Anything that can hold water for more than a week in urban backyards (e.g. potted plants, dog bowls, buckets, birdbaths, tin cans, and tires)
Gutters and runoff drains
Surveillance is one of the three major components of Vector Control. In order to develop operational abatement and response practices, first, we must determine what species of mosquitoes, the species composition of mosquitoes, spatial distribution, and emerging and current threats are present in our jurisdiction. Surveillance is the backbone of every mosquito control operation. Through implementation of the current cluster trapping practice for surveillance, the SBCMVCP's staff learned a better understanding of the Aedes mosquito and how to better protect public health. Since community outreach and education are vital for the abatement of this type of mosquito, the implementation of this practice has proven to be one of the best tools utilized by SBCMVCP. It allowed us to determine what type of training and educational materials would be needed for the population we serve and how to determine the areas that needed to be addressed first, based on the number of mosquitoes trapped and identified in the area.
The implementation of the cluster trapping practice has been useful for SBCMVCP to:
Determine changes in the abundance of Aedes mosquitoes
Evaluate efforts by comparing pre-implementation and post-implementation data utilizing the current trapping practice
Obtain a more accurate measurement of the existing Aedes mosquito population in our jurisdiction
Make appropriate managerial decisions regarding abatement and response
Provide appropriate training to SBCMVCP staff and community residents
Development of the cluster trapping practice started mid-2016 in order to respond to emerging threats in the contiguous United States and to ensure public health in the communities we serve. The current practice was implemented in March 2017.
The SBCMVCP stakeholders are city managers, city councils, public works departments, code enforcement agencies, and the public. Educational material and individual home inspections, where Aedes have been identified and trapped, are offered free of charge to all residents in our jurisdiction. The home inspections are done via block surveys in a pre-determined area or in response to a day-biting mosquito complaint. The information regarding our surveillance, operations and community outreach and education activities are distributed through the program's website, social media, door-to-door surveys, health fairs and community events.
Program funds were used for the surveillance staff to research information regarding Aedes mosquitoes, traps being utilized by other programs and develop a proposal for changing trapping practices. The CO2 traps cost an average of $100 per trap, plus the cost of dry ice and batteries. The development of initial educational flyers and brochures cost $1,200.
By using existing technology, SBCMVCP was able to keep the operating costs to a minimum. Since staff conducts research and develops practices as seemed appropriate, no additional training was needed.
Tracking practices for collecting and understanding data were also already being utilized in the program, no additional work was needed.
The annual average salary for a Vector Technician is $97,730. The annual average salary for a Public Service Employee (PSE), who sets, collects and services traps as well as conduct door-to-door surveys is $33,280.
Outcome/Achievement of Objectives
The cluster trapping practice has assisted us in fulfilling our overall goal of improving the quality of life for all residents and visitors by protecting public health, promoting safety and preventing environmental hazards. The public is being informed and educated regarding the symptoms, risks, treatment and prevention of Zika, as well as, how to eliminate potential breeding sources in their homes.
As of November 21, 2017, 1,170 Aedes mosquitoes have been trapped, identified and tested utilizing the cluster trapping practice, in comparison to 68 in 2016.
Over 2,500 homes have been inspected and abated for Aedes mosquitoes, over 120 trapping sites have been created (6 CO2 traps per site), and $150,000 in grant funding has been secured for a period of 16 months to solely address the Aedes surveillance and abatement activities.
Evaluation of Practice
Data collection and analysis demonstrate the cluster trapping practice success. The performance measures included number of water sources identified and abated (Aedes code added to existing database), number of mosquitoes trapped, number of day-biting mosquitoes service calls received from the public, and number of people reached through door-to-door surveys and community events.
The cluster trapping practice evaluation results have been vital in achieving SBCMVCP goals and objectives.
Continuous efforts to enhance surveillance and operational practices are helpful for SBCMVCP to meet the public's needs and to improve the quality of life for all residents and visitors by protecting public health, promoting safety and preventing environmental hazards. Constant communication with public officials and all stakeholders is vital to prevent public misinformation and increase public knowledge regarding emerging threats.
SBCMVCP will continue to collaborate with city officials, neighboring vector control districts, the California Department of Public Health and the public. Our focus continues to be the identification and abatement of any mosquito species or vectors which may affect public health within our jurisdiction.
Stakeholder Commitment to Sustain the Practice
SBCMVCP has been holding meetings with city managers, city councils, and public works departments throughout the county in order to ensure their trust in our program and collaboration in keeping the public informed and safe. The benefits of the cluster trapping practice has also offer us an opportunity to secure funding for necessary activities for 16 months and potential future ongoing funding.
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