By Michael Luong, NACCHO Environmental Health Intern
Summer may be coming to an end, but mosquito and tick season continues until the first frost hits and temperatures are consistently under 50 degrees Fahrenheit.
With warming temperatures across the country and vector-borne diseases on the rise, local health departments and other local vector control organizations have a crucial role to play in protecting their communities from mosquito- and tick-borne illnesses year round.
- Pesticide resistance testing
- Making treatment decisions using surveillance data
- Routine standardized vector surveillance
NACCHO’s Vector Control Toolkit offers numerous resources to assist vector control programs in improving their ability to perform these and other core capabilities in vector surveillance and control. Several of these resources are highlighted below.
Pesticide Resistance Testing
Pesticide resistance is an overall reduction in the ability of a pesticide to kill its target pest, meaning that a pesticide may no longer work or only partially work – even when used as directed. Pesticide resistance can be product specific, or it can develop to a certain class(es) of product. Resistance to pesticides is a potential threat to all mosquito control programs. Local vector control programs can help reduce pesticide resistance by using pesticides only as needed, monitoring pesticide resistance routinely, and managing pesticide-resistant mosquito populations through better coordination among mosquito control programs, insecticide manufacturers, state agencies, and other stakeholders.
This tool provides an overview of resistance testing for larval mosquitoes. The companion video includes a rationale for monitoring resistance in mosquitoes; an overview of dose responses and how the dose response changes as resistance to larvicides evolves in a mosquito population; the different types of larval mosquito control agents; the supplies needed for carrying out bioassays; instructions for bioassay set-up and making stock solutions of control agents; and instructions for interpreting the bioassay results.
The CDC bottle bioassay is the preferred method of performing insecticide resistance in vector populations. It is designed to help determine if a particular insecticide formulation is able to kill a vector at a specific location at a given time. This tool provides a laboratory manual and an instructional video on how to perform and interpret the CDC bottle bioassay.
Aedes aegypti and Aedes albopictus are known vectors of Zika, dengue, yellow fever, and chikungunya viruses, and they are present in parts of the United States. This tool outlines CDC-recommended considerations that should be taken when performing surveillance and pesticide resistance testing for these mosquito species.
Primarily targeted at public health technicians, vector control program managers, and policy-makers, this tool offers basic information on resistance mechanisms, provides readers with a better understanding of factors that may lead to the development of pesticide resistance, and discusses basic principles for avoiding the development of pesticide resistance.
Making Treatment Decisions Based on Surveillance Data
Conducting surveillance on the types and numbers of vectors in an area, as well as the potential viruses they may be carrying, helps vector control organizations determine when, where, and how control activities should be implemented. Vector programs should develop and implement a treatment-decision strategy to ensure that the most appropriate control measures are used for an area. Programs aiming to implement integrated pest management and integrated mosquito management should also establish action thresholds, criteria that trigger chemical and non-chemical vector control activities based on pest populations or environmental conditions. Lastly, vector control programs should work to monitor and evaluate the effectiveness of their control efforts.
This tool provides the rationale for treating based on surveillance data and setting action thresholds. Integrated Mosquito Management is a comprehensive mosquito prevention and control strategy that strategically uses all available mosquito control methods to reduce their numbers while maintaining a quality environment. This tool describes the best practices and core concepts of this approach.
This policy demonstrates how a program systematically determines its control decisions based on gathered data. By defining risk levels for human disease and documenting triggers and considerations for control measures, the City of Mansfield has created a phased plan to prevent the spread of vector-borne disease.
Routine Standardized Vector Surveillance
Surveillance, or the monitoring of vector populations, is a critical step to implementing effective vector control and health promotion activities. According to the AMCA, a scientifically-driven surveillance program is the backbone of every mosquito control operation. Vector control programs should use surveillance to maintain awareness of the abundance and distribution of mosquito populations, assess control efforts, measure vector populations over time, and support appropriate and timely interventions.
A practical example of routine surveillance, this tool contains an annual report that summarizes the processes for larval, adult mosquito, and human surveillance, as well as the results of systematically gathered surveillance data by the Mosquito Surveillance and Control Program in Allen County, Indiana.
Aedes aegypti and Aedes albopictus in response to the risk of introduction of dengue, chikungunya, Zika, and yellow fever viruses. This guidance covers topics such as of specimen collection, mosquito-based surveillance indicators, and the handling of field-collected adult mosquitoes.
More resources on vector surveillance and control can be found by searching the Vector Control Toolkit in the NACCHO Toolbox. The NACCHO Toolbox is a free, online collection of public health tools that have been created and shared by members of the public health community. To view the Vector Control Toolkit, visit the NACCHO Toolbox and select “Vector Control Toolkit” from the Toolkit’s dropdown menu.
If you have any questions about these tools or would like to submit a tool of your own to the Vector Control Toolkit, please contact the NACCHO Vector Control Program at firstname.lastname@example.org.