Risks
This specific population control technique (biopesticide lab-reared Wolbachia bacteria-infected mosquito release) has NEVER been done in the state of Hawaii. Southern house mosquitoes have never been documented as used for Wolbachia IIT stand-alone field release anywhere in the world. The East Maui project area is the largest Wolbachia mosquito release of any kind globally to date.
A primary risk that was not adequately addressed in the Maui Environmental Assessment (EA) is the potential for increased pathogen infection due to horizontal transmission of the introduced Wolbachia bacteria strains between the introduced lab-infected mosquitoes and the existing “wild” mosquitoes. Horizontal transmission is defined as the spread of an infectious agent from one group or individual to another, directly or indirectly.
Tropical disease and vector expert Dr. Lorrin Pang (speaking as a private citizen) shared his concerns about the state’s “Mosquito Control Research Using Wolbachia-based Incompatible Insect Technique” project:
- “…with new life forms coming to the islands, there is too much potential for unexpected, dangerous, irreversible ‘evolutionary’ events. This is especially true when the new organisms cannot be contained to their target ecosystem. Already there are published papers pointing out the real threat of horizontal spread of the novel Wolbachia beyond the male Culex mosquito.”
- “Proponents may be right that this intervention will save the native birds in the short-term, but long-term consequences to other island ecologies and to these same native birds may ultimately be detrimental. When one realizes the latter, the damage may be impossible to recall or repair, like the effect we’ve seen with so many other invasive species in Hawaii.”
- “It is enough to say that the new Wolbachia strain can spread horizontally as a life form to other mosquitos (say Aedes, the vectors of human disease) and perhaps create that Wolbachia female Culex which everyone is bending over backwards to avoid via lab contamination.”
- “How is this supposed to be self-contained? Horizontal spread has the potential to be a disaster that cannot be recalled. The bacterium is a life form, and you might not be able to turn back the clock by simply shutting off the male mosquito ‘fountains.’ ”
If existing wild female mosquitoes become infected with the introduced bacteria strain via horizontal spread, those wild females now become introduced-strain-infected. This would essentially cause the same concerns as those due to accidental release of misidentified lab-reared females. These infected females can produce viable offspring. They can breed with the lab-reared introduced males. The capacity of those offspring to spread disease is unknown.
Population replacement is also a risk. Through this evolution, the wild mosquitoes could be replaced by the lab-bred mosquitoes, thereby establishing the lab-bred invasive population in the wild.
A 2020 study out of Singapore describes the implications of Wolbachia-based biocontrol agents, presenting evidence of horizontal spread and evolutionary events.
Additional concerns that have not been adequately addressed in the EA include:
- Accidental release of misidentified lab-reared female mosquitoes (who bite and breed)
- Horizontal gene transfer of Wolbachia DNA to other invertebrates (the movement of genetic information between organisms – a process that includes the spread of antibiotic resistance genes among bacteria, fueling pathogen evolution)
- Impacts on the endangered birds should mosquitoes become more capable vectors of avian malaria
- Impacts on humans and birds should mosquitoes become more capable vectors of West Nile Virus
Not addressed at all in the EA is the concern of Biopesticide wind drift (movement of the lab-bred mosquitoes through wind to unintended areas) which could effect not only the efficacy but the safety of the project.
Included in the Maui EA is the acknowledgement of several potential impacts that would require mitigation measures and practices. These potential impacts are highly concerning:
- Wildland Fire: possible wildland fire ignition by helicopters
- Vegetation: concerns regarding the spread of invasive weeds
- Wildlife: noise-producing activities adversely affecting native wildlife
- Special Status Plant Species: disturbance to native and special status plant species and activities that could accelerate erosion
- Special Status Wildlife Species: impacts to nesting or roosting sites, noise disturbances
- Special Status Species Habitat: disturbance to special status species, adverse impacts within critical habitat
- Invasive Species: transport and establishment of introduced species including weeds and diseases/pathogens
- Cultural, Historic, and Ethnographic Resources: disturbance of traditional cultural practices
- Human Health and Safety: threats to human health and safety
- Acoustic Environment: noise impacts on visitors, nearby landowners or communities, wilderness, and sensitive environmental resources
- Visitor Experience: noise and viewscape impacts
- Wilderness Preservation: impacts to wilderness character
- Nene (Hawaiian Goose): speed limits, endangered species on-site
- Hawaiian Forest Birds: drone hovering, risk that breeding birds would flush from active nests, helicopter rotor wash
- Hawaiian Seabirds: seabird breeding season
- Hawaiian Waterbirds: speed limits, endangered species on-site
- ‘Ope’ape’a (Hawaiian Hoary Bat): drone hovering, risk of disturbing pup rearing, helicopter rotor wash, disturbing day roosting bats
The EA also notes that many thousands of mosquito packaging release packets will litter the forest floor and canopy throughout the duration of the project (likely at least 20 years):
- “Incompatible mosquitoes would likely be released in small biodegradable packages designed to open upon contact with the canopy or forest floor.”
- “These mosquito packages dropped via aerial means would result in an impact to the undeveloped quality of wilderness for as long as they remain in the environment (until they biodegrade).”
- “Although many thousands of release packets would be dropped across the project area throughout the duration of the project, the small packets would be spread diffusely and the biodegradable material would decompose quickly; thus, the impact to the environment would be negligible.”
- “Although the final design has not been decided upon, agency and private partners are committed to designing release packaging that is suitably biodegradable and will maintain biosecurity protocols. However, until a final product is designed, specific decay rates or other relevant variables are not known.”
In the “Cultural Impact Assessment” of the EA, interviews with Native Hawaiian lineal descendants and recognized cultural experts were conducted. Everyone interviewed expressed concerns about the impacts of this project, including:
- Bacteria used for the mosquito mitigation method spreading elsewhere into the environment
- The method of using bacteria to make mosquitoes infertile
- Maui as an experiment or pilot project
- The story of bringing the mongoose to kill the rat, thereby creating a new problem
- Impact on birds
- The project area as sensitive, with people depending on native flora and fauna for their livelihoods
- The project area as a fragile system and the impacts on the system as a whole
- Potential impact to cultural resources and traditions
- Harm or impact to other species
- Effect on humans
- An infected mosquito biting a person
- Possible residual effects in the environment
- Impact on other animals like ‘opae (shrimp) and ‘o’opu (goby fish) that live in streams
- Impact on animal habitats
- Whether or not adequate studies and research have been done
- Possible residual effects on other insects
- Impact on native plants used for lei making, weaving, and other cultural practices
- Possible impacts on water sources
- Keeping the public informed
- Skepticism of the sterility of the Wolbachia mosquitoes
- Impact on other islands from water sources connected through tides and currents
Per the Environmental Assessment:
“There was concern expressed by informants that the project could potentially and adversely impact native flora and fauna…If the project and concerns about the use of this biocontrol discourage practitioners from conducting their traditional or customary practices, it would be an adverse effect to these cultural activities.”
“Impacts to cultural resources were considered and dismissed from detailed analysis“
According to the U.S. Department of the Interior Strategy for Preventing the Extinction of Hawaiian Forest Birds, “although used world-wide for human health, Wolbachia IIT is a novel tool for conservation purposes and its degree of efficacy in remote forest landscapes is unknown.” This plan is an experiment on our island home. There are serious risks, and the outcome is admittedly unknown.