Vector-Borne Disease: CDC Report Outlines Key Steps for Prevention and Control in U.S.
By Liz Dykstra, Ph.D., BCE, Allison Gardner, Ph.D., and Meredith Spence Beaulieu, Ph.D., BCE-Intern
In September, the U.S. Centers for Disease Control and Prevention (CDC) released A National Public Health Framework for the Prevention and Control of Vector-borne Diseases in Humans. Americans are at increasing risk of exposure to vector-borne diseases domestically and abroad, yet federal, state, and local public health agencies remain inadequately prepared to execute timely and effective responses to these threats (see, for example, the National Association of County and City Health Officials’ 2016 nationwide vector control assessment, which is set to be updated this year). The Entomological Society of America and more than 25 like-minded organizations that make up the Vector-Borne Disease Network view this new report as an important step forward, as it outlines strategic priorities to address these shortcomings and enhance detection, prevention, and control of vector-borne diseases in the U.S.
Vector-borne disease prevention and control has experienced sporadic funding over the decades, with spikes in emergency funds following the detection of novel vector-borne pathogens, such as West Nile and Zika viruses. However, funding typically quickly declines after the initial response is over, and the failure to sustain funding at a stable level inhibits the long-term maintenance and efficacy of vector and vector-borne disease surveillance and control programs. In particular, the recession of 2008 depleted funding for local and state health departments, reducing many to legislatively mandated activities only.
The Framework describes a range of challenges that must be addressed to protect Americans from the growing public health threat of vector-borne disease. These challenges include few vector-borne disease prevention and control measures, limited capacity to respond to vector-borne disease outbreaks, stressed surveillance systems, inadequate diagnostic capability, lack of vaccines and limited options for treatment, lack of quality interconnected data, and innovation in tools for prevention and control outpacing the regulatory process.
While annually reported cases of tick-borne disease more than doubled between 2004 and 2018 and both endemic and emerging mosquito-borne viruses pose a continual threat, recent surveys published in the Journal of Medical Entomology show inconsistent and often under-supported patchworks of tick and mosquito surveillance and control programs across the country. Vector monitoring and response capacities vary greatly between states, as some have tax-funded vector control districts while others have these services performed by city- or county-level health departments (with or without dedicated funding streams for vector control). The level of engagement in vector surveillance and control directly by state health departments also differs by state, primarily due to funding constraints.
State public health departments depend heavily on funding from the CDC via annual Epidemiology and Laboratory Capacity (ELC) cooperative agreement awards. Through ELC grants, CDC’s Division of Vector-Borne Diseases provides funding and technical assistance to state, local, and territorial health departments to implement and maintain surveillance for human diseases and their vectors, improve diagnostics, and implement and evaluate prevention strategies. When ELC funding drops, surveillance programs are quickly hindered. The recession of 2008 resulted in critical losses of surveillance and control capacity at state and local health departments across the country. The threat of Zika virus bolstered funding and helped bring back some capacity in 2016, but the COVID-19 pandemic wiped out these gains during the 2020 season as pandemic response overwhelmed state and local health departments. While this shift of focus during an unprecedented global pandemic is understandable, the lack of dedicated resources for vector surveillance and mitigation may make us particularly vulnerable to future vector-borne disease outbreaks.
The Framework emphasizes the importance of vector-borne disease at a time when public attention is already focused on infectious disease and public health. Developed jointly between five federal departments—Health and Human Services, Agriculture, Defense, Interior, and Homeland Security—and the Environmental Protection Agency, the Framework‘s objectives are to reverse the current upward trends in vector-borne disease incidence and to increase the nation’s ability to protect the U.S. population from these diseases. The Framework‘s solution is a multi-pronged, coordinated approach based on five goals:
- Better understand when, where, and how people are exposed to and get sick or die from vector-borne diseases
- Develop, evaluate, and improve tools and guidance for the diagnosis and detection of vector-borne diseases
- Develop, evaluate, and improve tools and guidance for the prevention and control of vector-borne diseases
- Develop and assess drugs and treatment strategies for vector-borne diseases
- 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.
The Framework details the strategic priorities that will provide a road map for critical vector-borne disease prevention and control activities. While the Framework sets federal goals in service of these activities, it also reinforces that the federal government is not able to address these complex challenges alone, and it calls for partnerships among health departments, public health and vector control agencies, healthcare providers, academic and industry partners, policymakers, and patients to reverse upward vector-borne disease trends.
In December 2019, the Kay Hagan Tick Act was signed into federal law, authorizing $150 million to strengthen various aspects of the nation’s efforts to monitor and manage vector-borne disease. The law includes reauthorization of the CDC’s five Vector-Borne Disease Regional Centers of Excellence for an additional five years with $10 million in funding to each through 2026 as well as $20 million to states. Additionally, the act authorizes and tasks the Secretary of Health and Human Services (HHS) to develop and implement an official “national strategy” for vector-borne disease prevention and control based on the goals and strategic priorities laid out by the Framework.
State and local health departments work with mosquito abatement districts and universities to monitor pathogen activity in vector populations and provide education on disease exposure risk. Expanding this network to include a variety of partnerships so that vector-borne disease issues can be sufficiently addressed throughout each state would help address the current patchwork of surveillance efforts, both in who conducts surveillance and where surveillance occurs. Meanwhile, maintaining sustainable and dedicated funding for vector-borne disease activities, including through ELC grants or other mechanisms, will ensure continued capacity at the state and local health department levels.
While the Framework presents simply the foundations for a nationwide strategy on vector-borne disease mitigation, it is a critical first step in unifying surveillance, prevention, and control efforts to improve public health capacity. The forthcoming national strategy to meet these goals, now in the works at HHS, will detail specific objectives, activities, performance metrics, and a coordination and monitoring plan, and it will be prepared in consultation with stakeholders—including the ESA through its leading role with the Vector-Borne Disease Network.
U.S. Centers for Disease Control and Prevention
Liz Dykstra, Ph.D., BCE, is the public health entomologist in the Office of Environmental Public Health Sciences at the Washington State Department of Health. Email: firstname.lastname@example.org. Allison Gardner, Ph.D., is an assistant professor in the School of Biology and Ecology at the University of Maine. Email: email@example.com. Meredith Spence Beaulieu, Ph.D., BCE-Intern, is assistant director of the Triangle Center for Evolutionary Medicine at Duke University. Email: firstname.lastname@example.org. All three are members of the 2020 Class of ESA Science Policy Fellows.