Shortly after the Fourth of July, Nick Booth had excruciating knots in his stomach accompanied by intense headaches as the roundworm parasites he’d ingested made their way from his intestines through his spinal cord to his brain.

The 29-year-old Waimanalo farmer was sent home from the emergency room at least three times before being admitted into the hospital. He said doctors had no clue what was wrong with him. It wasn’t until three weeks later that health officials confirmed Oahu’s first case of rat lungworm disease in seven years.

“They sent me away with nothing, really. A couple days later it was just unbearable,” said Booth, who had a severe burning sensation throughout his limbs. “You can feel them crawling through you. … Especially once it got into my brain, I could feel it progress. That was pretty horrible. I don’t wish my worst enemy that.”

The Department of Health confirmed the latest case of rat lungworm disease in a Hawaii island infant last month, bringing the statewide total to 17 so far this year. State officials have been grappling with how to control rats, snails, slugs and the relatively new semi-slug — 75 percent of which are estimated to carry the disease. The worms can cause significant damage as they travel through the body and attack nerve endings.

“In the MRI, you literally see chunks of where they dug through my brain. The biggest chunk is 1 inch long by 5 millimeters wide that they ate out of my brain,” Booth said.

Elko Evans, the owner of the organic lettuce farm where Booth works and lives, insisted doctors test his employee for the disease.

“The fact that we have 5,000 parasites in a quarter-inch snail, that’s terrifying. It was a nightmare,” said Evans, who owns Honest Greens, which previously sold about 100 pounds of lettuce a week. “Seeing what this kid has gone through, it’s devastating. He was just moaning and barely could walk. You could not imagine the amount of pain being inflicted.”

It was clear that medical providers on the island weren’t familiar with rat lungworm symptoms even though Booth had contracted a rare type of meningitis caused by the infection, Evans said.

Booth was not given antiparasitic medicines until three weeks later. There is no specific treatment for rat lungworm. Health Department officials said they do not promote antiparasitic drugs because they have not been proved effective and may make symptoms worse.

“I realize that it’s a rare thing that’s not (commonly) here and that was the reasoning behind not being more proactive, but in hindsight I wish they would’ve gave me the antiparasitics earlier,” Booth said. “It was already into my brain and pretty much all around it by the time they gave me antiparasitics. I should have had antiparasitics as soon as I got ill when it was in my stomach. They’d be killed and flushed out. Instead I’m looking at possible permanent nerve damage.”

Nikki de Foster, Booth’s then-girlfriend who lives on a separate Waimanalo farm, said the ordeal felt like a “horror movie.”

“It was like never-ending watching him in pain. He felt like there were aliens taking over his body,” she said. “At one point I couldn’t even touch his skin. He felt like he was burning. It was really the worms burrowing into his brain. If you look at his CAT scan, he has black spots in his brain. He has a little bit of brain damage. They poop in there, they’re eating your brain tissue and then dying. It’s the worst thing I’ve ever seen.”

Booth’s suffering was so bad that he would pass out in “mini-comas,” de Foster said. Now he is living on at least half a dozen painkillers and antiseizure medications.

Evans said: “If he doesn’t have one of his meds, he’s a miserable human being. He’s basically masking his symptoms all day long. He’s maybe half … the human being that he used to be. It’s a horrible, disabling disease.”

Health officials said the department’s Disease Investigation Branch must determine if a case meets a specific criteria before it runs tests for the disease. There are no readily available blood tests.

The test itself, which examines antigens in the spinal fluid, actually takes less than a day, said department spokeswoman Janice Okubo, adding that the state will “never delay testing beyond what’s necessary to verify that a person meets the criteria.”

When larvae carried by slugs and snails get into a person’s system, they travel to the brain and form into worms that shed antigens, or toxins, according to the Health Department.

“When it molts, it sheds antigens and that go into the spinal fluid, and that’s what they find in the spinal tap test. If the worm has not molted and it’s in your brain, then it may not be shedding antigens into your spinal fluid, so a lab test may not find antigens and your results will be negative,” Okubo said. “It is a very serious disease, but it’s not a common disease. We don’t want people to get overly fearful. Fruits and vegetables are good for you as long as you wash them.”

Evans, the farm owner, said he has since stopped growing leafy greens and started cultivating turmeric, beets, squash, papaya, eggs and catfish.

“I’m so nervous about eating anything raw. We ripped up everything before anything was diagnosed,” he said. “For me to have 30 pounds of baby greens taken to market, I can’t guarantee it won’t have a quarter-inch snail. If I’m not going to eat it, I’m not going to sell it. It’s just not worth it.”

John McHugh, administrator for the Department of Agriculture’s Plant Industry Division, said: “Rats are the main host for this thing. The state doesn’t have the resources to control rats throughout the entire state. They’re everywhere on these islands.”

He added: “It wouldn’t surprise me if we have a couple more cases before the year’s end. But the fact there’s been 17 cases … as far as the public’s health is concerned, it doesn’t seem to me like that is a real huge number.”

Booth’s former girlfriend, de Foster, also said she believes she contracted the disease, likely from drinking from the garden hose. Her symptoms included severe headaches and stomach pain, vomiting, tingling in her hands and feet, and numbness in her tongue. Her case was not officially confirmed by the state since a spinal tap came back negative. Booth’s first few spinal taps also were negative for the infection, but eventually tested positive.

The same doctor who treated Booth said de Foster’s symptoms were stress-related and sent her home with Tylenol.

“It was like a stabbing pain in my stomach. It feels like an ice pick almost — a hot stabbing pick. That’s when they’re burrowing through your intestines,” she said. “It’s the worst feeling I ever had in my life.”

Equally distressing is doctors couldn’t do anything to alleviate the pain, she said.

“When I went into the ER and told (the doctor) I thought I had rat lungworm, the guy checked my breathing and said, ‘Wow, your breathing sounds great. I can’t believe they thought you have rat lungworm,’” de Foster said. But the parasite affects the lungs of rats, not humans.

“It shows how uneducated even hospital staff is on this,” she said. “I was shocked. It’s just a matter of time before it happens to somebody else here — it really is.”