On February 1, 2016, the World Health Organization declared a public health emergency of international concern related to Zika virus. Zika’s potential links to microcephaly and Guillain-Barre Syndrome, serious conditions that can lead to lifelong disability and even death, make Zika a pressing public health concern. With no existing cure or vaccine, vector control is currently the primary method of preventing Zika transmission.
Zika virus is transmitted principally by Aedes aegypti mosquitos, and may also be transmitted by the related species, Aedes albopictus. Known as the “cockroach of mosquitos,” Aedes aegypti in particular has adapted well to life in close proximity with humans, increasing the challenge in controlling it effectively. Aedes aegyptimosquitos typically fly only 50-100 meters, making control of adults via aerial pesticide spraying, which targets airborne mosquitos, less effective. They breed in water held by items commonly found in backyards, including gutters, dog bowls, trashcans, birdbaths, and even bottle caps.
Mosquito infested jurisdictions in the U.S. have been exploring multiple approaches to control Aedes mosquitos due to their capacity to spread diseases – not only Zika, but also the dengue, chikungunya and yellow fever viruses. In January 2016, Hawaii launched its “Fight the Bite” campaign to eliminate backyard mosquito breeding conditions through the provision of educational materials and abatement resources. In February 2016, Hawaii Governor Ige declared a state of emergency related to mosquito-transmitted conditions, including dengue and Zika.
Public health officials in Charleston, South Carolina are planning house calls to conduct property surveys, with owner permission, to provide advice on elimination of breeding sources as the mosquito season approaches. Texas and Florida already have robust mosquito control programs. Houston is increasing its education efforts, and Hillsborough County (Florida) has already paid workers overtime for mosquito control activities near the home of a Zika-infected person.
For Aedes mosquito control, the Centers for Disease Control (CDC) recommends reducing water-holding containers and larvicide treatments for water sources that cannot be eliminated. While these preventative measures are the first line of defense, adulticide treatments, such as insecticide spraying, are also recommended to control areas with large mosquito populations and to treat the areas surrounding the homes of infected persons.
Implementation of mosquito abatement efforts depends in part on legal authority. Mosquito control districts in some states allocate specific authority, funding, and resources to localities. Elsewhere, jurisdictions derive legal authority via their police power ability to regulate for the public welfare and safety, including controlling disease vectors and eliminating public nuisances.
All U.S. states and counties have laws dealing with public nuisances. Many of these laws allow public health officials to classify a private property as a public health nuisance and require clean-up activities by the property owner. If mosquito-transmitted Zika becomes widespread in southern states as projected, these laws may be used to require property owners to eliminate mosquito breeding sources.
Depending on the abatement measure, permits or other approvals from federal and state agencies may be required. Under the Federal Insecticide, Fungicide, and Rodenticide Act, pesticides must be approved by the Environmental Protection Agency (EPA), applied according to EPA directions for use, and applicators must be properly trained. Additional state and federal laws, including the federal Clean Water Act, may require spray permits or environmental impact assessments, some of which may be waived short-term, if an emergency declaration is in effect.
Despite established authority on mosquito control, legal challenges may arise. Application of pesticides may be opposed by environmental protection organizations and concerned individuals. Shortly after the New York City Department of Health announced its pesticide plan in the wake of the West Nile outbreak in 1999, the City was sued by a coalition seeking an injunction under environmental protection laws. The injunction was denied at a hearing in which several CDC experts testified on the benefits of pesticides. The City was allowed to spray according to its schedule while the litigation proceeded, resulting later in a settlement.
Compliance with applicable legal and regulatory requirements is essential to developing a successful mosquito abatement campaign. In addition to source reduction, larvicides and adulticides, community outreach, public education and surveillance activities are also critical. With integrated pest management focusing on mosquito prevention, not simply on pesticide-based mosquito control, health authorities can bite back against Aedes mosquitos.
This guest post was prepared by Alicia Corbett, J.D., Adjunct Faculty and Affiliated Professional, and Sarah Wetter, J.D. Candidate (2017) and Senior Legal Researcher, Public Health Law and Policy Program, Arizona State University.
The Network for Public Health Law provides information and technical assistance on issues related to public health. The legal information and assistance provided in this document does not constitute legal advice or legal representation. For legal advice, readers should consult a lawyer in their state.
Support for the Network is provided by the Robert Wood Johnson Foundation (RWJF). The views expressed in this post do not necessarily represent the views of, and should not be attributed to, RWJF.