The state Legislature is pushing along two bills that would explore potential mosquito control methods in Hawaii.

HB 297 would have the state Department of Agriculture review the possibility of importing and releasing mosquitoes that carry a bacteria strain to act as a “mosquito birth control.”

“You only release males, so the mosquitoes are effectively sterile mosquitoes males because they have this bacteria,” Cynthia King, an entomologist for the Department of Land and Natural Resources, said. “So when they mate with a female, those females will lay eggs, but the eggs will never emerge.”

The mosquito, Aedes aegypti, is already established on Hawaii island. Nearly all mosquitoes of this species carry the Wolbachia bacteria, but those with a certain strain of the bacteria would be incompatible with those found in Hawaii — their offspring would be unable to reproduce.

It also can suppress the development of viruses inside the mosquito.

While A. aegypti is already present in Hawaii, it is not approved to be imported from out of state. HB 297 would look to add it to the list of approved animals.

HB 1546 would have the University of Hawaii assess all the available methods to eradicate mosquitoes in the state, which include using genetically modified mosquitoes.

Mosquitoes carry diseases harmful to humans, but mosquito-transmitted avian malaria and avian pox are also part of the reason over half of Hawaii’s 50 native forest birds have gone extinct, with half of the remaining species appearing vulnerable to following suit.

“The restoration of those birds probably isn’t going to proceed successfully until we can do something about disease transmission,” said Dennis LaPointe, a research ecologist with the U.S. Geological Survey.

The birds are safe in higher elevations where it is too cold for mosquitoes, but climate change is expanding the insects’ territory.

More promising methods beyond Wolbachia involve genetically modified mosquitoes.

One involves a “gene drive” system in which detrimental genes could propagate themselves within mosquito populations, eventually crashing them.

Gene drive systems could be cheap and effective, and harmless to nontarget species. LaPointe said it could offer a more permanent, “one-way eradication of a species,” which is something that cannot be done using the Wolbachia method.

“You have to keep flooding the environment with these males,” he said. “It would be really hard over a large landscape to eradicate mosquitoes entirely.”

The challenge is getting the public on board with the idea of releasing genetically modified mosquitoes.

“For the most part, the consensus is that most people are not comfortable with that,” King said.

LaPointe said the fear of releasing genetically modified organisms is that nobody knows what could happen, and if something goes awry, there might be no way to stop it.

No genetically modified nonplant organisms have been released in Hawaii for the purpose of controlling a certain population.

LaPointe said a more recently explored technique, which would involve killing the Wolbachia bacteria in A. aegypti and “transinfecting” it with the bacteria from another species of mosquito already in Hawaii, could achieve the same effect as importing Wolbachia-carrying mosquitoes.

He said the “transinfecting” technique is relatively new and difficult, but nothing would have to be imported or genetically modified. A Wolbachia method to controlling mosquitoes has fewer hurdles to overcome.

“Although it’s not the final solution to it, it provides a better technique for covering more landscape without any of the questionable issues that usually hang around modified organisms,” LaPointe said.

Whatever method the state decides to use would be an upgrade because Hawaii currently does little to control, monitor and eradicate mosquitoes to prevent disease outbreaks.

The Department of Health’s Vector Control Branch, which is in charge of preventing and responding to disease outbreaks, was scaled back greatly in 2009 because of the nationwide recession. Within days the branch laid off 41 of its 58 employees, and for a few years it was basically nonfunctional.

“(The branch) had people that would maybe provide consultation over the phone, but there was nothing active,” said Grace Simmons, manager of the branch. “They weren’t doing inspections, they weren’t doing any kind of active control.”

She was hired in 2016, when the DOH received funding for 20 vector control positions due to the dengue fever outbreak that affected over 200 people on Hawaii island from 2015 to 2016.

Lynn Nakasone, ex-officio at the DOH, said vector control staff from neighbor islands and even non-vector control staff from the DOH were sent to Hawaii island to respond to the outbreak.

“It became very obvious that the vector control program was nowhere near capable of doing that kind of stuff,” she said.

Today the branch has essentially been restored but still is not fully functional.

Mosquito control on the state level is performed on a case-by-case basis and often limited to pesticide use and source reduction, which can sometimes mean simply educating the public. The branch is still looking to establish adequate mosquito surveillance.

The bills this session could eventually lead to a means by which the branch can again effectively control the state’s mosquito population beyond pesticide use.

Both bills have been referred to the Senate Committee on Ways and Means; the committee will make a decision on HB 1546 Wednesday at 10:25 a.m., and HB 297 needs to be heard by Friday in order to continue on.