This week, the U.S. Environmental Protection Agency (EPA) issued an emergency exemption to the state of Hawaii, allowing the use of Wolbachia mosquitoes to help control an invasive mosquito species that is a major spreader of avian malaria, which does not infect humans, and is contributing to endangered bird species decline in the state. The Hawaii Department of Agriculture submitted an emergency exemption to EPA to use the Wolbachia mosquitoes in state, federal, and private wildlife conservation areas in Hawaii, specifically the counties of Honolulu, Hawaii, Kauai, Niihau, and Maui.
Due to climate change-induced temperature increases and Hawaii’s warm climate, mosquitos breed throughout the year, and are invading the last remaining native bird habitats. The emergency exemption will allow the use of Wolbachia mosquitoes to treat up to 20,000 acres of wildlife conservation areas to protect threatened and endangered forest bird species including the Hawaiian petrel,`I`iwi, Nēnē, and others that are at risk of extinction because they are highly susceptible to avian malaria. Avian malaria has already caused widespread declines of several endangered bird species in Hawaii and has been a major driver of the extinction of other bird species on the islands. With no current management tools to effectively address the invasive mosquito threat, the forest bird species are at risk of extinction within the next decade, thus directly impacting native ecosystems and forests and potentially indirectly causing the decline of other threatened or endangered species.
“DQB Males” are live male Culex quinquefasciatus mosquitoes, which don’t bite people, that are infected with the DQB strain, a particular strain of Wolbachia pipientis. Wolbachia are common, naturally occurring bacteria found in many insect species. The DQB Males mate with wild Culex quinquefaciatus females that are not infected with the DQB strain, which then produce eggs that do not survive. With continued releases of the DQB Males, the local mosquito populations are expected to decrease.
After conducting robust scientific assessments, EPA concluded there are no human health or ecological risks of concern with this exemption. Additionally, EPA evaluated the potential effects on threatened or endangered species and determined that the exemption is "not likely to adversely affect" 29 endangered or threatened species. In fact, the effects are expected to be wholly beneficial for species threatened by wild Culex quinquefaciatus mosquitoes. Based on these conclusions, EPA informally consulted with the U.S. Fish and Wildlife Service (FWS), which concurred with EPA’s determinations with no further comments or concerns.
Additionally, EPA has received strong support for this exemption from state and federal agencies and other stakeholders, including the Hawaii Department of Land and Natural Resources, FWS, the U.S. Department of Interior’s National Park Service, and several wildlife conservation groups.
This emergency exemption is limited to the areas of Hawaii mentioned above for controlling Culex quinquefasciatus mosquitoes and is valid for one year. EPA is requiring monitoring of the Culex quinquefasciatus mosquito populations in the areas where the releases will occur. If the prevalence of the Wolbachia strain in DQB Males reaches a certain threshold in the local mosquito population, the State of Hawaii will end the releases to prevent establishment of this strain. The product is not available for use by the general public or public health programs, and the state of Hawaii is responsible for oversight of the use of DQB males under the exemption.
To read the approved emergency exemption and for additional information, including EPA’s risk assessments, response to comments and the FWS concurrence letter, please see docket EPA-HQ-OPP-2022-0896 at www.regulations.gov.
Original source can be found here.