[announcer reading] [music playing] [birds chirping] [narrator] Long ago, in an unknown place, when creatures were beginning to explore and discover and connect... there was a rat... and a snail... and a parasite.

No one knows how it happened, but somehow their lives intertwined in a strange and fateful way.

[brush rustling] Then humans wandered in, and some of them got very, very sick.

Today, more than ever, they're still falling ill.

When I got sick with Rat Lung, I was in Kapoho, Hawai i. I would surf, and I would skateboard every day.

And then I started getting sick.

When I got taken to the hospital, they thought it was the flu, and they sent me home.

That just allowed the-- the worms, the parasites, to continue migrating through my body.

I don't think they had made it to my brain by that time.

Suddenly I was in the-- what I would call the acute phase of the illness, where I had so much pain in my body, I couldn't wear clothes, I couldn't tolerate sunlight on my skin, I couldn't tolerate wind.

Nothing could touch me.

As that week went on, he progressively got much weaker.

He wasn't crying.

He wasn't talking.

The only thing that he could do was move his head back and forth and open and close his eyes.

I have never imagined that I will get this disease as a healthcare professional.

I know the prevention.

I thought I can prevent it like the other diseases, like tuberculosis or tetanus, you know, but obviously it's not the case.

This disease is a very-- is an emerging disease, and it's spreading, and we're just sort of one station on the way as it spreads across the world.

Give us the next hour, and we'll tell you about an exotic tropical parasite now in Asia... Africa... South America... and beyond, that sometimes causes lifelong neurologic damage, even death.

Today, it could be closer than you think.

Accidental Host: The Story of Rat Lungworm Disease [wings flapping] Some call it "danger in paradise."

Welcome to the island of Hawai i, an American epicenter of a silently globalizing, food-borne parasite now present in warm, humid regions of five continents.

Rat lungworm not only enters rats and snails, but innocent bystanders.

The story begins with some basic biology.

Most of the time, the parasite cycles between rats and snails, its natural hosts.

In rats, the adult worms live in pulmonary arteries, where the parasites mate.

[heart beating] [rat chitters] After offspring hatch, rats eventually pass droppings that can harbor thousands of invisible larvae.

Snails and slugs eat those larvae-laden droppings.

Other rats get infected by eating those snails and slugs.

Humans become "accidental hosts" when they, too, consume larvae living in mollusks or other contaminated foods.

[siren blares] What happens next can vary from insignificant to devastating.

The parasite doesn't want to be in us.

We're not going to complete that parasite's life cycle.

But the consequence of just interacting with that biologic ballet between the rat, the parasite, and the snails and slugs can be a significant aspect for disease in an individual.

Some parents in Hawai i are already on high alert.

We did have a kind of close call once.

Kingston put one of the empty shells into his mouth, and, um, that really scared us.

Fortunately, nothing happened.

We gotta just keep up on it and always be looking, you know, because everything goes in the mouth.

All right, come on.

[Dr. Melish] What may happen with children is about the age that a child starts to crawl, they pick up almost anything they can find.

Possibly they just get stuff on their hands, but more likely, they probably eat them.

[Balucan] Noah was in teething season.

He had a fever one day.

I treated it with Tylenol.

Fever went away.

But as that week went on, Monday, Tuesday, Wednesday, he progressively got weaker to the point that he wasn't moving at all.

So Thursday morning, we took him to his regular doctor, and she sent us straight over to the hospital.

By that night, we were medevacked here.

[Dr. Melish] By the time they came in the hospital, he had weakness in his legs much more than his arms, but he had generalized weakness as well, difficulty in holding up his head.

He had a swollen bladder.

And that evening, he became totally unable to breathe, so as an emergency, a tube was placed in his, uh, trachea, and he was put on a ventilator.

So he stayed in the hospital from mid-November until just before New Year's, had his first birthday at a time when he was completely paralyzed in our intensive care unit.

So when Noah first came in, his imaging was remarkably normal.

You can see his spinal cord here.

Follow-up scan showed some widening of the cord here and brighter signal in the cord, which is all suspicious for edema or transverse myelitis.

And here in his brainstem, we see these little regions of dark signal, which look like blood products or little hemorrhagic tracks of the worms actually traveling through the brain.

[shutter clicks] [Dr. Ansdell] Larvae, when they're ingested, are microscopic.

You can't see them with the naked eye.

They get to the brain and the spinal cord, and they develop.

They grow.

And they can become visible to the--to the naked eye, probably a centimeter or so long.

[narrator] Angiostrongylus cantonensis is the formal name of the worm that traveled to Noah's brain.

[film projector whirring] Although first found in rats in China in the 1930s, it was not until the 1950s that Australian researchers reported something novel.

Not only did certain Angiostrongylus species live in and near rats' lungs, they also invaded rats' brains, the same journey later found in people as well.

To parasitologist Larry Ash, the discovery was stunning.

I cannot give them enough credit for having found this very weird life cycle involving mollusks and a migration in the rodent host through the brain.

That is the beginning of it.

In humans, confirming the same migration was not as simple.

From time to time in Asia, rat lungworm appeared in patients' eyes, suggesting possible invasion of the brain.

But meningitis, an inflammation of the covering of the brain, was a far more common clinical syndrome, both in Asia and several Pacific islands.

[film projector whirring] The final piece of the puzzle fell into place in Honolulu in the 1960s.

That's when an autopsy revealed rat lungworm deep in the brain of a man from a mental hospital who died of severe meningitis.

Once we had identified the parasite in the brain of a person, then it was how did this person become infected?

We already knew the life cycle going through slugs and snails, so that's when I started my studies looking at slugs and snails in Hawai i.

Those studies, conducted in market gardens both in Hawai i and French Polynesia, found something new.

Sometimes the parasite seemed to contaminate fresh, leafy produce.

Until then, dishes containing undercooked freshwater shrimp or land snails were seen as likelier sources of infection.

[ukulele playing] On a recent trip to the Big Island, Larry Ash went hunting for snails at a farm outside Hilo with a group that included biologist Robert Cowie.

Oh, lookit.

There's a bunch of 'em right there.

- All right.

Wow.

- Oh, yes.

Here we go.

Yeah, they're good-sized.

Oh, there's another one here, too.

- Oh, yeah, they're everywhere.

- Wow.

Wow.

They really love that.

These are giant African snails.

- Yes.

- Right?

The story was that they were originally brought to Hawai i as a food source.

- By the Japanese.

- Yeah.

They were brought in for a number of reasons.

One was for food, but interesting, another reason was because some people felt that it would be nice to have big snails crawling around in their yards just as... - Oh, my God.

- Yeah, really.

[narrator] But no one wants this strange creature called a semi-slug, a recent arrival in Hawai i that can carry heavy loads of rat lungworm.

[Rollins] So they have a really high density of larvae per tissue, and also, um, a high prevalence.

So a lot of the population that we have screened is infected, higher than some of the other species.

[music playing] [narrator] Although Angiostrongylus cantonensis inhabits many different snails and slugs worldwide, in a recent survey conducted on the Big Island in the Puna District, an astounding 75% of semi-slugs harbored Angiostrongylus larvae.

Larry, you've never seen these before, have you?

I've never seen them before.

- Right.

- Yeah.

So Larry hasn't seen them before, because these were first recorded in Hawai i only in 1996.

- Wow, really?

- And on this island, they were only recorded first in 2004.

They're really interesting.

And these are-- they're heavily implicated in transmission of Rat Lungworm Disease, but so are other-- other species, but these seem to be particularly heavily infected with worms.

Coinciding with the arrival of the semi-slug, there really does seem to have been an increase in the number of cases and an increase in the severity.

And we don't know for sure if-- if it was the--responsible, but it looks pretty suspicious to me.

We had a cluster of cases that were severe enough to wind up in our intensive care unit.

That was unheard of prior.

And some of them, so severe that they needed to be put on a ventilator, needed feeding tubes, and needed intensive, intensive medical support.

When I got sick with Rat Lung, I had slugs everywhere.

It was called the semi-slug, so I was aware of them.

And then I started getting sick.

I had serious joint pain and stiff neck and headaches and just feeling of unease and-- When I got taken to the hospital, the third time, I was admitted.

I wasn't able to urinate.

After two weeks, I went into a coma.

I was in the hospital for 4 1/2 months.

And it was a long haul.

He got a lot of hospital-acquired infections.

He had pneumonia, C. difficile, MRSA.

We had a lot of bad news.

He had hydrocephalus.

You know, it got very depressing.

Went into a coma on the 12th of January, and the first words he spoke, it was right around the beginning of April.

I literally did not go home until he was released from the hospital.

These are my glasses.

Mom says they're too interesting.

[voice-over] The worms nibble on stuff.

I think my optical nerve was what was affected, and my left eye turned in, giving me double vision.

- [Howe] First walking.

- Gonna walk.

[McCumber] I had to relearn everything.

- Okay.

- Okay, here we go.

[McCumber] Relearned some stuff in the hospital, but I relearned how to walk at home.

A lot of people know somebody that's suffered this disease or, um, have suffered it themselves, and so it's very, um, close to the heart to people here in east Hawai i. Dr. Sue Jarvi heads a team of rat lungworm researchers at the University of Hawai i's School of Pharmacy in Hilo.

She's also a strong advocate for patients in her community.

[Dr. Jarvi] It's a horrendous disease.

It's a game-changer.

You know, a lot of people that have been infected, they can't work again.

One of their family members has to take care of them.

So not only is it, uh, mentally and physically devastating, um, it's also financially.

You know, a lot of these people, their finan-- their financial situ--situation is ruined, um, because of this disease.

[ominous music playing] [Martell] There is a large number of people out in the community with severe disease, and they basically went through the whole disease process without any medical attention.

And they will describe months of being delirious... nearly comatose... not eating... severe headaches.

So there's a group out there, um, that never received medical attention.

[narrator] But even people who quickly seek care often struggle to get the correct diagnosis, people like Esperanza Hilton, who's been a nurse for 25 years.

Hey.

Ooh.

I started having headaches, and I am not the headache person.

So a week passed by.

I'm taking Tylenol, and its not improving.

Then, even though I really don't want to go to E.R., I know my body.

So when I went to E.R., same diagnosis.

They said it's a stress headache.

"You can go home.

I'll give you narcotics."

"No, it's not."

"What do you want us to do?"

is what...[laughs] I said, "Spinal tap or just-- "What about giving me steroids, you know?

Or antihelminthics?"

So they finally admitted me.

[Martell] Espie's story is very typical.

It is quite common for patients with Rat Lungworm Disease to go to urgent care or the emergency department two or three times before the-- they're taken seriously enough that somebody will do the spinal tap.

This petite, little lady is one of the toughest people I know, and then to see her, um, just in such severe pain where--where she-- her head is just killing her, she can't keep her eyes open.

She's, like, hiding from the light, hiding under-- under the covers.

It's really hard to-- to put words to--to how, um, disturbing it is.

After three months, I felt like I'm 90% of myself.

And then another month passed by, 95%, 98%, and I'm back to the bedside care and taking care of the patients in the intensive care unit.

I asked my husband, "Okay, it's time to go for a hike again," 'cause we love outdoors.

That's all that we love to do, hiking, camping.

He chose to go to Halape, which is like 11 miles one way.

I reached there, put my feet in the water.

It's like, "Hey, I'm alive again!"

[narrator] Espie isn't sure how she got infected, but experts have a pretty good idea.

[Dr. Cowie] I think that the way most people get infected is inadvertently, probably by eating a small snail or slug that contains a whole bunch of rat lungworm larvae in it, in amongst lettuce leaves in a salad, for instance, or perhaps mixed up in a smoothie and that it's actually the snail itself, slug, snail, that you have to eat in order to become significantly infected.

[narrator] Semi-slugs pose a special challenge, because they readily enter human habitats, from kitchen gardens to household trash, even your front porch.

The other thing is, in the juvenile phase, they appear to be fairly translucent, so they may be hard to discern among leaves, particularly leafy vegetables and other produce.

[steel drum playing] [narrator] Produce was a clear-cut culprit in the year 2000, when a large shared salad served to tourists in Jamaica caused a landmark outbreak of Rat Lungworm Disease.

In this case, the accidental hosts were a dozen medical students from Chicago enjoying spring break.

I remember being excited to hang out with my friends.

We had had this plan to go to Jamaica.

It was a big group of us, so it was gonna be, like, sort of exciting.

We did everything from sightseeing, exploring.

We went horseback riding.

So we decided to cap off a week-long adventure with going to a really nice restaurant.

They did this whole table-side presentation of--of the Caesar salad, and, um, there was nothing to indicate that the Caesar salad was contaminated in any way.

So I remember very clearly that meal that we had, 'cause I know that that's what got me sick.

One of my friends who had been on the trip started having neck pain and meningitis-like symptoms.

But I didn't connect it at all to our trip, because it had been three or four weeks since we had gotten back.

It was a Saturday, and Monday morning, I was waking up, getting ready to go to class, and I remember that my neck hurt, and the lights hurt my eyes, and I had some numbness and tingling in my arms.

And I thought, "Oh, no, I have meningitis."

[Dr. Longano] Word came from the triage nurse that there were several people who were Northwestern early medical students, who had just come back from Jamaica, and all were manifesting the same symptom-- headache, neck stiffness, fever.

[narrator] The clinical picture spelled meningitis.

Lumbar punctures were performed, and preliminary tests run.

Then came the bombshell... eosinophils... unusual pink cells in the students' fluid that pointed not to a virus or a bacterium, but a parasite.

[Dr. Longano] I was absolutely flabbergasted, because there were eosinophils present in the spinal fluid.

This is something I had never seen before.

I had never heard of it before.

[narrator] Once CDC investigators ran additional tests, The New England Journal of Medicine published a full report.

In brief, 12 travelers who ate the Caesar salad developed Rat Lungworm Meningitis in the month following their final meal in Jamaica.

Seven others who didn't stayed well.

Julia Grabowski, the most severely affected traveler, suffered wracking headaches, requiring multiple lumbar punctures.

I was in the hospital for 20 days, and during that time, I had probably between seven and ten spinal taps in the hospital, and then I had-- was having them after I was discharged as well.

The spinal tap actually felt good.

I had very high intrathecal pressure, so it felt nice to have it relieved.

When it was confirmed to me that I had, uh, Angiostrongylus cantonensis, I-I think it was, uh... surreal and disbelief at the same time.

I knew that that's what it was, but then I was thinking to myself, "Why me?

How, out of-- How does this even happen?"

When I saw this patient, I was completely clueless about the life cycle and the natural history of the organism.

This was completely undiscovered country for me at that time.

The fact that parasites are actually migrating through your body i-is creepy.

[singing in Hawaiian] [narrator] In January 2017, the disease struck the eastern side of Maui.

First, two newlyweds who honeymooned in Hana developed serious, unexplained symptoms, later diagnosed in San Francisco as rat lungworm in the brain.

The following month, Jacques "Leokane" Pryor, a well-known singer and resident of Hana, also suffered mysterious ailments.

[singing fades] [Pryor] One of the first things I remembered was, um, itching all over my body and my skin.

You know, I've had rashes and, you know, too much sunburn.

This was different, because it was moving throughout my body, and I thought that's really strange.

Then I developed a low-grade fever, um, 99.5 to 100 degrees, every day.

And then I started to get headache.

I was fatigued.

So I kept going to the local clinic.

It got worse and worse and worse.

I mean, there were several weeks of that, and then, uh, it was obvious that-- a-and to the folks at the clinic, too, that something else was--wasn't right, and they recommended a series of blood tests to figure out wh-what might be going on.

[narrator] In fact, what was going on with Jacques was not unique.

Before reaching the nervous system, where they typically die, rat lungworm parasites often cause many baffling complaints.

[Dr. Ansdell] It's a difficult disease to diagnose.

The earliest symptoms of the disease may reflect migration of the larvae as they pass through the liver, the heart, the lungs, or get trapped, maybe in the kidneys or in the skin, so it'd be almost impossible to diagnose the disease based on things like, you know, some abdominal pain, some respiratory symptoms, some nausea, some vomiting, maybe some diarrhea, and maybe a skin rash.

So it's really hard for physicians, busy physician, to think-- be thinking right up front, "This could be Rat Lungworm Disease."

But then, when the parasites make it to the brain, that's when the symptoms reflecting involvement of the central nervous system, uh, become apparent.

[narrator] But for Jacques, symptoms alone were not enough to spur further action.

The turning point came when he asked a medical friend to scan his lab work.

And my eosinophil count was up, and he was alarmed with my symptoms and that and said, "Tomorrow morning, I want to meet you "at the hospital on the other side.

"F-First thing in the morning, we're going in to the E.R., "and I am going to, um, advocate for you, and we're gonna get a spinal tap."

So when we find the eosinophils in the spinal fluid, that really clinches the diagnosis of an eosinophilic meningitis, and often that can mean the patient has, um, Angiostrongylus, or rat lungworm.

[narrator] But what about patients who don't have eosinophils in their spinal fluid?

After reviewing two dozen cases from her own hospital, Marian Melish reached a startling conclusion.

We've learned from these cases something which is not appreciated at all, is that you don't even have to have the telltale eosinophils if you get to see the patients early enough.

[narrator] In Jacques' case, however, the cells were present, and his fluid also tested positive for rat lungworm DNA.

The next question was treatment.

High-dose steroids, which suppress inflammation, have long been the traditional mainstay.

Nonetheless, newer guidelines recently published in the journal Parasitology recommend that patients also receive deworming drugs like albendazole, with one caveat.

We think as soon as there's a reasonable suspicion of the disease, patients should be started on treatment, and evidence about the value of corticosteroids is pretty good.

If you're going to use a drug like albendazole, you have to give it as early as possible.

It's the young larvae that are killed by this drug.

Once they get older, then it doesn't work as well.

[narrator] Veterinarians have learned this from treating dogs, who can also contract rat lungworm.

In fact, in parts of Hawai i and Australia, the prompt use of steroids and dewormers for a suspected infection is often far more common in puppies than in people.

So this is Athena, a pit bull, that presented in November, when she was about four months of age, with symptoms of, um, unable to walk and, um, falling down and just weak for, you know, 24 hours.

So when she presented, physical examination was performed.

At this point, Rat Lungworm Disease is, um, high on the list of differentials.

What the treatment is composed of is low dose of corticosteroids and, uh, dewormer.

Uh, fenbendazole is something we use here.

Uh... [narrator] Veterinarian Alfred Mina has also observed that dogs regularly treated for heartworm, a different migrating parasite, rarely get angiostrongyliasis.

And, like, this one's normal.

And... Hey, girl.

Does this mean that preventative treatment should also be given to people?

Experts are torn.

But not Hilo resident Chaunda Rodrigues.

In January 2020, after buying a lettuce and avocado sandwich and biting into an infected semi-slug that actually stuck to her teeth, she actively sought albendazole and never fell ill.

In others, forgoing treatment can have lifelong consequences.

Jacques Pryor never received albendazole and only briefly took steroids.

Four years later, he still has daily pain.

And though he sometimes visits Hawai i, he no longer lives there.

I spent two days in the hospital while they ran many, many tests on me.

They gave me steroids on those days.

Uh, becau-- This was something-- I don't like to have regrets in life, but I do regret that I refused to keep taking steroids when they released me.

I still didn't even know anything, really, about the illness.

I never fully recovered, whatever that might be, other than surviving fully, being ambulatory, not being in a coma, not having paralysis, being alive.

So I consider myself a survivor.

Nonetheless, the nerve damage in my body has remained.

[narrator] For Noah Balucan, who spent his first Christmas in an ICU, the acute illness was even scarier.

But nine months later, his prospects were looking up.

[Dr. Melish] In caring for Noah, we all had a great surprise when he started to improve.

The worst case that I had-- previously had cared for, just inexorably got worse and worse and worse and died.

Um, and, uh, we had them on-- that person on the same treatment.

But in pediatrics, we just don't ever give up.

We just keep on, so we kept on treating him, caring for him on a total-care basis, because he was completely immobile and dependent on a respirator.

And he slowly started to say-- move one part of one hand and, uh, get some facial features.

We were patient.

We let the doctors do whatever treatment they needed to do, run whatever test they needed to do, and they did, and it worked.

[inhales] Good boy.

[Dr. Melish] Seeing him today, I didn't expect that he would be completely back to normal, but I had seen him in April, at which point, he had recovered to a point that I never would have expected.

At that time, he was, um, crawling very fast, but not yet either willing to or able to walk.

But he was clearly then and now above expected development for verbal, personal, social, and fine motor.

He can do all the things you would expect an almost two-year-old to do, but he cannot yet walk very well unaided.

Okay.

Whoa, whoa, whoa.

[narrator] In Hawai i, whether it's invading an innocent toddler like Noah, a beloved spouse, honeymooning tourists, or a puppy, rat lungworm doesn't play favorites.

But who and where will the parasite strike next?

And can wildlife offer an early warning?

It's known that rat lungworm can infect a whole bunch of different animals worldwide.

Primates, chimpanzees, orangutans, gibbons, monkeys of various kinds have been infected.

There are birds that have been infected.

Those are all sort of ramifications of having this parasite, you know, in and around us.

[narrator] This brings us to Florida, where in recent years, animals in a zoo in Gainesville have also suffered Rat Lungworm Disease.

The first animal to show anything was one of our lemurs, and we were perplexed, like, had no idea, and of course meningitis and those sorts of things came up, and it was really scary.

We actually thought we were gonna lose that animal, and with our veterinarians at the University of Florida, uh, particularly Dr. Wellehan, they were able to determine what it was.

[narrator] A decade earlier, however, a gibbon in Miami and a privately owned orangutan died of rat lungworm.

When--When I first met the orangutan, she had been referred up from southern Florida.

She was still young.

She was-- She was an adolescent female.

She was very sweet.

Um, and she couldn't stand.

And because she was neurologic, we did a spinal tap.

When it came back full of eosinophils, we were immediately concerned about a parasitic disease.

- You guys did a necropsy... - Yeah.

- and found the worms... - Yes.

- in the--the brainstem.

- Yes.

Right, and so then we actually went down to the-- the compound where she was being housed and collected snails, and we also collected rat feces.

We found it in pretty much everything that we--we sampled.

The whole life cycle was right there where--where she lived.

[narrator] Dr. Heather Walden is a leading researcher who has already found Angiostrongylus in one in five rats and one in 50 snails in a survey she conducted in Florida.

Welcome to my lab.

It's so great to have you here finally.

Oh, it's great to be here.

Thanks for having me.

So I wanted to show you some of the things that we have been able to collect in the state of Florida.

Yeah.

These tiny babies are, um, the kinds of snails that we think may be implicated in the transmission of rat lungworm to--to humans, - because... - Yeah, look how tiny.

- a very small baby like that... - Very, very tiny.

with lots of parasites in it.

In a heavily infected snail, in the tens of thousands of larvae.

[narrator] Walden's work will not end soon.

Having followed infections in Hawai i, she fears they could someday also plague the entire southeastern United States.

And so do others, including Dr. Stephen Ostroff, a longtime food safety expert at both the CDC and the U.S. Food and Drug Administration.

[Dr. Ostroff] So the circumstances in Hawai i aren't necessarily unique to Hawai i.

We know that this parasite is present in other parts of the United States.

But given the right circumstances and the opportunity to introduce another vector, which may be what we refer to as more competent than the ones that are presently there, it can happen there, too.

[Dr. Gosnell] And as the ecology of places change, interactions with different peoples, the world becoming a smaller place, and the sharing of foods and unfortunately some of the pathogens, we can sort of probably expect to see some of these geographically distinct infections popping up in different places of the world.

Parasites are not going away.

You know, certainly, uh, in--in Hawai i here, rat lungworm is not going away.

The rats are not going away.

You know, so we have to be, uh, more clever about how we can, um, improve uh, or lower, uh, risk of exposure.

[narrator] In Hawai i and other places where Angiostrongylus thrives, that means reaching everyone, from farmers to food sellers, even eight-year-old kids.

- One for me, one for them.

- Yeah.

What's that?

What is that?

Is that a worm?

- Right there.

- Yeah, there's a few.

- Whoa!

- That's a big one.

[narrator] In school gardens in Hawai i, youngsters learn about snails and slugs that can carry rat lungworm.

[Howe] We're training the kids to be experts on this, where they can then share that information with their ohana, with their communities, and they become the educators, and they take it very, very seriously.

[narrator] Kay Howe launched the program after her son Graham got sick.

Years later, she remains passionate about educating children.

One of the earliest comments that we had from a student-- And it was shortly after we did the second-grade activity book.

We made pre-visits to the classrooms before we introduced the book, and then we made visits after.

And one little second grader came up to me, and she said, "You know, I tell my little brother and sister not to touch those slugs and snails now."

When she told me that, I was like, "This is working."

Nothing.

Watching children interact and being excited about the biology of these organisms without having fear, but just understanding, will help protect them throughout their life, is really something that kind of makes me appreciate the science that we've instilled in the younger generation.

[Dr. Ostroff] There needs to be a lot of education to the local populations, not only to warn them about the disease, wh-what the symptoms are like, but also what they can do to prevent themselves from becoming infected.

When we think about highest risk of crops that carry rat lungworm, I also like to think of not so much that these crops are risky, but that our behaviors are sometimes risky.

[narrator] Dr. Luisa Castro has spent years teaching about agricultural safety, everywhere from scientific meetings and public forums to farmers' markets.

There's a huge growth of farmers' market in our state.

Of course everybody and every island has their specialty, and they'd like to have this opportunity to showcase their produce and their farms to our visitors and our kamaaina, our locals.

What we have to make sure is that, at these farmers' markets, that we also are taking advantage of educating at that point, because there's people who, yeah, think that it's already safe, that, you know, the product has been cleaned and washed and that all they have to do is take it home and put it in their blenders and that they can just eat it, no problem.

And so this is a great opportunity at farmers' markets to also educate our buyers, our vendors, market managers, everyone about the, uh, challenges with the rat lungworm.

[narrator] Steve Ostroff, who recently met with Hawaiian farmers, also warns that government regulations are not without loopholes.

Any grower that grows and markets less than $25,000 worth of produce annually is exempt from having to do any of the things that the Food Safety Modernization Act, or FSMA, calls for.

In addition to that, if more than 50% of your total sales are directly to consumers or directly to commercial establishments, mostly restaurants, those farmers don't have to do most of the things that FSMA calls for, as long as their total sales are less than half a million dollars a year.

[narrator] Those loopholes also highlight why local restaurants and residents need to stay vigilant.

We started this pro--protocol about 10 years ago.

- Wow.

- For Casey Halpern, executive chef at Café Pesto in Hilo, working closely with growers and meticulous washing are key.

Definitely been a big concern for me, because as a-a chef, I want to support farmers, and to think that people might not be having lettuce because of concerns, it--it really hurts.

Uh, goes into the second bath.

[voice-over] Over the years, we've had to make adjustments to the way we do things, and one of the big adjustments was how we handle our lettuces.

By picking it up out of the water, we're leaving behind things.

Takes about an hour to wash the lettuce, versus 15 minutes the old way.

It's been an-- an ongoing experience, but we're always gonna put that safety as the number one priority.

For myself and my family, how we would protect ourselves against something like rat lungworm is, again, sort of listening to what my grandmother had told me back before.

Wash it.

Cook it.

Be safe.

[Hilton] Before I got sick, we always have a daily salad on our table, but after that incident, no more.

I grew up in the Philippines, and basically my first 20 years of life, my mom is always cooking vegetables.

So, you know, I'll just go back to the old ways.

You know, even myself, I have to remind myself, because for so long, you know, you would, like, get a cantaloupe, cut it open, you know?

And I have to remind myself, "No, you need to scrub that and wash it and--" A-And we need to start thinking differently, especially with climate change occurring.

Um, everything is changing.

I remember being a kid and just picking up product from the ground, produce, guavas, and just eating.

But in the last 10 years, there has been a big change.

I have noticed, um, the slugs and snails that I'd never noticed before now on our properties.

And so we are now very wary about, yeah, you just don't do that.

[narrator] That's good advice for tourists as well.

Every year, Hawai i welcomes millions of them, but how many, even doctors, know about rat lungworm?

I literally had no clue that this is a problem in Hawai i.

In fact, I had just been to Hawai i, and I was completely oblivious to this idea that, my gosh, this--this disease is present in paradise.

[Dr. Ostroff] You have this massive tourism industry in the islands, and we know that some of the cases have occurred in visitors, and so more needs to be done, even though you don't want to do something that would scare away tourists from coming to Hawai i, but they ought to know about health risks that, um, they could be exposed to in the islands.

[narrator] Dr. Kenton Kramer, a professor of tropical medicine, couldn't agree more.

Kramer currently heads the Governor of Hawai i's statewide task force on rat lungworm.

Aloha, everyone.

The tourism agency should target individuals that are going to stay in bed and breakfasts and outside the hotels or established restaurants, because it is people that think this is paradise, that go out and consume fruits and vegetables that aren't properly washed, that are at highest risk for acquiring the infection.

[narrator] In some settings, even so-called healthy foods can carry risk.

[Dr. Longano] I love them.

I'm a--I'm a proponent of a plant-based diet.

I myself eat very little meat.

Uh, I was devastated to hear that my green smoothies could be harming me.

[narrator] The reality is, all over the world, people have favorite foods that could carry larvae.

In Thailand, it could be undercooked seafood or snails.

In Jamaica, a local salad.

In Brazil or Hawai i, a fresh, blenderized juice.

But no matter how or where rat lungworm invades an accidental host and whatever illness it causes, diagnosing that host will continue to be an uphill battle until doctors are better informed and testing improves.

Angiostrongylus and Angiostrongylus meningitis are diseases which are, I'm sure, unknown to essentially the whole emergency-medicine community.

It's such an unusual presentation.

It's something that most physicians, you know, would not really consider without, you know, previous experience or education.

There needs to be more provider education, because it may not necessarily be the one who knows about this disease that a patient will come to, so that healthcare providers are more aware of what to look for and how to make the diagnosis.

[Dr. Ansdell] It's not the benign disease that you read in the textbooks.

Patients can be very ill.

Patients can die.

Patients can be left with long-term disabilities.

We really need a way of diagnosing this disease at the earliest possible stage.

My goal for the task force over the next 10 years would be to get a blood test that could be used as a rapid diagnostic test in the emergency room so that the patient would not need to get a lumbar puncture.

[Dr. Longano] The spinal tap, I think, is the rate-limiting step in this whole process.

A blood test would be absolutely wonderful.

And so the problems we've had here with people being unfamiliar with the disease, unfamiliar with the diagnosis, that's gonna be replicated across the world as it spreads.

[ship horn blows] [narrator] And spread, it will... via rats on ships and snails and slugs on plants that bring Angiostrongylus to even more eco-friendly settings.

Will it then infect even more humans?

That remains to be seen.

But to one accidental host, the question doesn't trigger fear.

It just means facing facts.

We all need to maka ala, be alert.

Um, of course, live in harmony, and, uh, love our Mother Earth, a-and not demonize any of these creatures, um, because they didn't want to get infected, either.

Nonetheless, with our changing world and everything chop suey, moving all over the place, th-this does await us, um, and it's important that we--we wake up now.

[ukulele playing] [singing in Hawaiian] [ukulele continues] [singing in Hawaiian]