Summer is Here and So are the Mosquitoes: Why Local Vector Control is Key to Combating Zika

Click the image to view the full “Zika in the United States” infographic on NACCHO’s website.

As temperatures rise well above 50 degrees throughout much of the country, mosquito season is in full swing, meaning many Americans are at a greater risk for mosquito-borne illness. This year’s risk factor is substantially higher with the emergence of the Zika virus (ZIKV), spread mainly through the bite of infected Aedes mosquitoes (i.e., Ae. aegypti and Ae. albopictus). These two species, especially Ae. aegypti, are characterized by their preference to remain close to human dwellings, directly increasing the likelihood of ZIKV transmission. The spread of ZIKV poses serious health risks because the virus can be passed from a pregnant woman to her fetus, potentially causing severe birth defects.

In the United States, nearly 6,000 ZIKV cases were reported since the start of 2016. This year’s first locally acquired infection happened just last week in Texas, and more cases are predicted to occur throughout the remainder of 2017. As a result, local health departments and their partners are increasingly turning their focus to prevent, prepare for, and respond to ZIKV-related health threats.

Local vector (e.g., mosquito) control agencies, typically supported by or embedded into local health departments are critical to mitigating the threat of ZIKV in the United States. Mosquito control efforts (e.g., insecticide use, source reduction) have historically been very effective at reducing the prevalence of mosquito-borne illness, especially for a virus like ZIKV, currently without a working vaccine. Mosquito control organizations conduct essential activities including monitoring the mosquito population, identifying ZIKV within the mosquito population, and treating breeding grounds to eliminate mosquitoes. Local health officials further support these efforts by educating the public and community partners on how to eliminate mosquito breeding habitats in and around homes and residences (i.e., the preferred breeding grounds for Ae. aegypti).

In light of the ZIKV outbreak, NACCHO assessed the current status of mosquito control and surveillance activities in local vector control programs within ten ZIKV priority areas (i.e., Alabama, Arizona, California, Florida, Georgia, Hawaii, Louisiana, Mississippi, Texas, and Los Angeles County). NACCHO and the Centers for Disease Control and Prevention (CDC) compiled findings and implications into this slide deck, aiming to further advance local vector control capacity and ZIKV response planning. NACCHO also created this complimentary infographic (partially pictured above) to highlight the rising impact of ZIKV in the United States and the critical role of local response agencies to preventing a national disease outbreak.

Since the slide deck was first released in December 2016, NACCHO has leveraged its findings to support the advancement of local vector control as an essential part of the national ZIKV response. Throughout the past several months, the assessment’s key findings and recommendations were highlighted at the CDC Foundation Vector Control Summit, the Preparedness Summit, and the National Environmental Association’s Annual Educational Conference. Each presentation emphasized the need to address a major gap discovered in local response capacity as a result the NACCHO assessment. More specifically, 68% of local agency respondents indicated that they lacked the resources or knowledge to routinely perform essential mosquito control activities.

These essential activities, also described as core competencies, were developed based on CDC and the American Mosquito Control Association (AMCA) guidance, and include the following:

  • Routine mosquito surveillance, standardized trapping, and species identification;
  • Larviciding and/or adulticiding capabilities;
  • Routine vector control (e.g., chemical, biological, source reduction, or environmental management);
  • Species specific activities; and
  • Pesticide resistance testing.

In addition to NACCHO’s presentations, all three conferences featured numerous other ZIKV focused sessions, many of which reinforced the need for sustainable vector control organizations to effectively protect public health against ZIKV and other vector-borne illnesses. Furthermore, the high level of audience engagement and feedback throughout these sessions highlighted preparedness concerns for 2017, particularly in light of diminishing funding for preparedness and response efforts.

Without a vaccine, mosquito control and preventing mosquito bites remains one of the most effective ways to prevent the spread of ZIKV. Prevention efforts and strategies need to include and consider perspectives from mosquito control experts, public health officials, epidemiologists, local businesses, and local government. Mosquito control, particularly for Ae. aegypti, requires active participation from all community members to identify potential breeding sites in and around homes and to eliminate them. Most often, this simply involves a walking inspection of property to empty water-collecting containers (e.g., toys, potted plants, clogged gutters, lawn decorations, etc.).

NACCHO recently formed a Vector Control Workgroup to collect and develop best practices for mosquito control, including checklists for property inspections. Public health professions and partners are highly encouraged to share best practice (e.g., educational or promotional materials, checklists, policies that support mosquito control, etc.) with the workgroup by emailing Chelsea Gridley-Smith at cgridley-smith@naccho.org. Additionally, NACCHO is currently conducting two new assessments to further examine local vector control and ZIKV impact related to maternal health throughout the United States. As the 2017 mosquito season continues throughout the United States, NACCHO aims to share insights, knowledge gained, and strategies in a collaborative effort to advance the nation’s Zika response efforts.

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