Washington, DC, September 23, 2024 – The National Association of County and City Health Officials (NACCHO), the voice of the country’s over 3,300 local health departments, released its 2023 Vector Control Assessment, showing that improvements made in mosquito surveillance and control capacity between 2017 and 2020 have started to decline, in part due to resource constraints as a result of concurrent public health emergencies including the highly pathogenic avian influenza (H5N1), Mpox, and natural disasters of increasing frequency and severity.

Local vector control programs protect the public’s health by providing front-line detection and control methods to prevent the spread of mosquito-borne and tick-borne diseases (i.e., vector-borne diseases). Seventy-seven percent of the nation’s local vector control programs need improvement in one or more core capacities to ensure the public’s health is protected from mosquito-borne threats (e.g., Zika, West Nile Virus, Malaria, and Dengue). Despite the lack of defined surveillance and control measures for ticks compared to mosquitoes, 51% of programs offer community education and outreach on preventing tickborne diseases like Lyme disease, a 16% increase from 2020. Increasing trends of vector-borne diseases require fully capable and well-funded local vector control programs across the U.S. and seamless integration into local and state departments of health.

Between 2017-2020, local programs increased capacity to conduct vector-related surveillance and make treatment decisions. However, since 2020, these improvements declined across all but one capacity area (ranging from a 1% to 11% decline, depending on the capacity area). Notably, “non-chemical vector control” capacity has steadily increased since 2017 (58% in 2017, 78% in 2020, 87% in 2023). Still concerningly, 73% of programs are not monitoring for pesticide resistance. The risk of using ineffective control methods could undermine the financial efficiency and effectiveness of public health interventions. Further, very few programs currently conduct tick surveillance or control activities, exacerbating gaps in data on tickborne disease cases, tick prevalence, and the expanding range of ticks due to climate change.

Other key findings include:

• The percentage of programs considered “fully capable” in mosquito surveillance and control decreased since 2020 (24% in 2020 vs. 20% in 2023), yet the improvements since 2017 are still evident (8% in 2017 vs. 20% in 2023).
• The percentage of programs reporting capacity for nearly all mosquito surveillance and control activities assessed dropped slightly from 2020 to 2023. The sole exception was non-chemical mosquito control capacity, which increased from 78% to 87%.
• Pesticide resistance testing was still notably lagging, keeping most programs from becoming fully capable in mosquito control and surveillance—with only 26% of programs reporting capacity in this area. This is a decline from 2020 when 31% of programs reported their capacity for pesticide resistance testing.
• One in four respondents (25%) reported tick surveillance activities, representing a slight increase from 2020, when one in five (21%) reported tick surveillance activities. Only 4% reported any type of tick control activity.
• Despite the lack of defined surveillance and control measures for ticks compared to mosquitoes, 51% of programs offer community education and outreach on preventing tickborne diseases like Lyme disease, a 16% increase from 2020.

The 2023 Vector Control Assessment findings validate several of the goals outlined in the National Public Health Strategy to Prevent and Control Vector-Borne Diseases in People, specifically the goal to “disseminate and support the implementation of effective public health and vector control products, tools, and programs to prevent, detect, diagnose, and respond to vector-borne disease threats.”

“With 77% of local vector control programs still needing improvement, the U.S. is not sufficiently prepared to respond to these threats. Surveillance and control of health threats posed by mosquitoes and ticks are important responsibilities of all local health departments,” said Lori Tremmel Freeman, NACCHO CEO. “Our 2023 Vector Control Assessment report indicates that improvements gained by local vector programs, which include local health departments, since 2017 have started to decline. These programs need consistent and increased support, training, and resources to address the health threats posed by mosquitoes and ticks.”

To understand the overall capacity of local vector programs, NACCHO fielded the 2023 Vector Control Assessment between November 2023 and December 2023 with support from the Centers for Disease Control and Prevention. The survey was the third iteration of a national assessment first conducted in 2017. Local vector control programs in forty-eight states and Washington, D.C. are represented in the sample. A total of 486 programs responded to the 2023 assessment, with a response rate of 30%.

Learn more about NACCHO’s work in vector control at https://www.naccho.org/programs/environmental-health/hazards/vector-control.

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About NACCHO

The National Association of County and City Health Officials (NACCHO) represents the over 3,300 local governmental health departments across the country. These city, county, metropolitan, district, and tribal departments work every day to protect and promote health and well-being for all people in their communities. For more information, visit www.naccho.org.