State officials are making a new push to combat rat lungworm disease, promising more public awareness efforts that urge vigilance in the cleaning of produce and planning to hire two workers dedicated to prevention.

But one local expert, who has studied the disease over the past five years, says the state should also be studying the effectiveness of commercially approved vegetable washes in killing larvae and figuring out cost-effective ways to help homeowners and farmers ensure the safety of their water catchment systems.

“Especially in East Hawaii, where basically the source of the problem is, most people are on rainwater catchment systems and a lot of people don’t treat the water properly,” said Susan Jarvi, a rat lungworm disease expert at the University of Hawaii at Hilo. “One of the problems is there aren’t any clear guidelines for homeowners or farmers using catchment water for agricultural purposes.”

State food safety inspectors and vector control staff are investigating produce from farmers with reported infestations and will work with local farms to ensure proper pest control, officials said.

So far this year rat lungworm disease has infected 15 people — the highest number of cases reported in Hawaii over the past decade.

Gov. David Ige said at a news conference Wednesday that cases of the disease are rare, but that state officials will be studying more about how people are infected.

“It still is a very rare incidence for the million or so residents and the millions who come to visit Hawaii,” Ige said. “The incidents have been few and we definitely are working to understand better the way that the parasite might be introduced to individuals so that we can be more targeted in how we respond.”

However, a significant number of cases go unreported because the state Health Department requires a spinal tap for definitive diagnoses, a risky procedure that many choose against, Jarvi said.

“It’s much more mainstream than we previously believed. They haven’t been reporting nonresidents,” she said. “At least a dozen people on the mainland have gotten rat lungworm here on Hawaii island. This has been an issue for years and years. There’s a whole pool of the population that’s not being reported.”

Rat lungworm disease is caused by parasites passed from the feces of infected rodents to snails, slugs and other animals. People can become infected when eating raw or undercooked slugs, snails, freshwater prawns, frogs, crayfish and crabs.

Symptoms include headaches, neck stiffness, tingling or pain on the skin or in extremities, low-grade fever, nausea and vomiting. The disease can also result in temporary paralysis of the face and light sensitivity. In rare cases, the infection can cause a serious type of meningitis that can be fatal.

“If you don’t die of the disease, it doesn’t mean you’re cured,” Jarvi said. “It can cause long-term or permanent neurological damage.”

The surge in rat lungworm cases on the Big Island and Maui prompted state lawmakers to appropriate $1 million in funding to address the disease. The state plans to use the money — $500,000 a year over two years — mostly to run a statewide media campaign on television and radio stations advising residents to clean their produce well. The state also plans to hire two temporary, full-time staffers to coordinate prevention efforts between government and the private sector.

In the first year, $300,000 will go toward public education. Another $100,000 will pay for the state’s first rat, slug and snail study to help officials determine why certain areas are more at risk than others, and identify disease routes and risks to guide vector control. The remaining $100,000 will fund vector control efforts statewide. The state is asking residents to eliminate snails, slugs and rats around residential home gardens and agricultural operations.

While the public awareness campaign is a significant part of the state’s efforts, Jarvi says thorough cleaning of produce using just water won’t prevent the spread of the parasitic infection.

“Certainly it’s not enough. What they’re basically saying is wash your vegetables. The issue with that is water does not kill the larvae. You can’t say it makes produce safe,” Jarvi said. “It makes them safer, but the larvae live in water. What studies in our lab have shown is larvae can live at least three weeks just in water. We had some larvae live 56 days in water.”

Department of Health Director Virginia Pressler said the state wasn’t aware that Jarvi or other researchers have a better solution to use than water to ensure produce is washed properly before it’s consumed.

“We would welcome any scientifically based research that showed something better than water,” Pressler said. “At the moment, the last we’ve heard from her is that water is as good as other washes currently used on vegetables. So if she comes up with something better, that’s great. We are working collaboratively with the University of Hawaii and all of the researchers there.”

A recent study found that 94 percent of 545 rats in Hilo were positive for the disease, Jarvi said.

“We’re a port town. Ships come up and dock. Rats jump on ships all the time. It’s really important to have really effective rat control. If our rats are 90 percent infected and jump on a ship … we’ve just exported rat lungworm disease,” she said. “It sounds like (the state is) taking this a little more seriously than it has in the past. The state is doing a lot more than it used to, which was pretty much nothing.”