Since the influx of media reporting about residents and visitors being infected with rat lungworm disease (RLWD) on the Big Island and Maui, there’s been a lot of fear in regards to buying and eating produce grown in the Hawaiian Islands. When I’m eating at restaurants, I’m asking servers if their making certain dishes with Hawaii produce. When grocery shopping, I’ve been turning away from the produce aisle and retreating the frozen vegetables section. There’s also been an alarming amount of speculation in regards to whether rat lungworm disease is in fact a threat.
It is. And Maui residents need to make early awareness, education and early detection top priorities–especially given that a recent bill (SB 272) that would have appropriated money to fight the disease just died in the state Legislature.
Rat lungworm disease, also known as Eosinophilic Meningitis, is extremely infectious. It’s contracted by ingesting the larvae of the rat lungworm parasite (angiostrongylus cantenosis). The RLWD parasite is a nematode, and part of a group of over 15,000 known round worm type, according to a UC Berkeley study titled “Introduction to the Nematoda.”
Rat lungworm disease and the parasite that causes it aren’t new; the disease is commonly found in tropical zones in South East Asia, China, Taiwan, Australia and the Pacific Islands. It seems to have arrived on Hawaii Island via a rat host. As for how it got to Maui, nobody seems to know–perhaps from a rat, semi-slug or another carrier species that reached Maui from an inter-island shipping container.
On April 17, the Hawaii Department of Health held a community meeting on rat lungworm at the Haiku Community Center. Presenters included Maui County Health Officer Lorrin W. Pang M.D., MPH., public health educators from the state Department of Health, representatives from the Maui Invasive Species Committee (MISC), Hawaii Food Council, UH Hilo and University of Hawaii’s College of of Agriculture and Human Resources (CTAHR). Pang started things off by saying that Mayor Alan Arakawa “considers this a crisis.”
Cases of the disease are clearly on the rise. On Maui over the last decade, there have been just two cases of infection. But in the past three months, there have been eight cases all rooting from Hana and East Maui.
Rat lungworm disease is spread from rats to slugs, snails, and other small species that eat rat feces. Pang presented a detailed lecture of how the RLWD parasite becomes infectious to humans and mammals.
“This parasite is complex,” Pang said. “It’s in the lung of the rat. The adult worm is in the lung vessel and starts to lay worms. The eggs pierce into the lung cavity of the rat, travel into bigger airways, and when the rat coughs or swallows its mucus, it goes into the digestive system of the rat and comes out in their feces. The rat feces are eaten by slugs and snails. The form of the worm goes through two more stages in the semi-slug or snail, transitioning into the parasite that infects humans and mammals.”
Lissa Strohecker, the Outreach & Education Specialist from MISC, urged the community to tell MISC as soon as possible if they find semi-slugs on their property. “Right now we’re at the very beginning of the spread of the semi-slug population in the community,” she said. Of course, there are lots of slugs, and they can be really hard to identify. MISC wants to find the hot spots in the community, and suggests that everyone verse themselves on how to control rats and slugs with bi-weekly and monthly treatments.
The public also needs to be extremely cautious to not spread the semi slug to other areas of Maui. This can be easily done by introducing a plant with an adult or keiki semi-slug into your home garden. In fact, this recently happened when someone purchased an Awa plant from Hana at a Kamehameha School fundraiser.
There are many ways that the rat lungworm parasite can be ingested and introduced to both a human and animal host. Adults, children and animals can be infected with RLWD (see “How To Protect Yourself” at the end of this story for a list of ways you can protect yourself).
The most common way to be exposed is by eating raw or insufficiently cooked slugs, snails, freshwater prawns, fish, frogs and contaminated produce. Though you and your family may not plan on eating any slugs or frogs soon, you should be very aware of activities made by you, your small children and household pets in the garden. It’s common for cats and dogs to play and chase after slugs and frogs in outside areas around your home, and for small kids to dig in the dirt, then touch their hands to their mouth. According to University of Hawaii-Hilo research, one Big Island resident believed that she contracted rat lungworm disease just by handling a slug. Another thinks she contracted the disease by stepping on one, and a sloth at the Hilo Zoo became paralyzed when infected with the parasite after playing with the slug.
Slugs and snails containing RLWD can also spread the parasite through their slime trails. Anyone who spends time in the garden and outside areas of your home should be very careful, and heed precautions to not bring the parasite from the outside to the inside of your home. You can safeguard yourself and your family by wearing gloves and shoes in the garden.
Slugs and snails infected with the rat lungworm parasite are often found around people and pet food that’s placed outdoors, underneath tarps, in compost bins and trash cans, underneath potted plants and weed cloth and inside leaves that are adjacent to the core of plants and leafy greens. Semi-slugs can even crawl up the sides of your house and enter your home (this is a special skill that they have), and they can also crawl into water tanks, infecting a whole water system by drowning and releasing parasites into the water through their skin.
Kay How of University of Hawaii Hilo* suggests that anyone with a water catchment system should transition to a 1-micron filter so that all water entering your home is potable and safe from the RLWD parasite. Even if your water tank cover is tight, she suggest that you remove your water tank cover and check for semi-slugs on a monthly basis.
Right now, state and county officials want to find out where exactly the semi-slugs are found.
“With regards to the semi-slug, the Dept. of Health and MISC will attempt to do a island-wide survey to see where the slugs can be found,” said Kenneth Yamamura, an Agricultural Specialist with the County of Maui. “Also important is whether or not the presence of the slug in a given area has the angiostrongylus cantonensis worms in them. In East Maui, there are about 30 to 50 worms inside a mature semi-slug. The percentage of semi-slugs carrying the infested worms runs from 75 to 85 percent of the population in East Maui.”
When rat lungworm larvae are ingested by humans and mammals, they perforate the intestinal tract, spread into your blood vessels and eventually reach the meninges, the casing of your spinal cord and brain. That’s where the larvae (round worms) will die. The larvae’s death sets off an eosinophilic reaction–basically, a battle to protect your immune system that’s manifested by an onset of symptoms. The only current way for medical professionals to diagnose a patient with RLWD is by administering a spinal tap.
Symptoms of RLWD include abdominal discomfort, flu-like symptoms, fatigue, nausea, headaches, neck pain, joint pain, inability to urinate, disorientation, sensitivity to light, visual disturbances and hyperesthesia (sensitivity to sensory stimuli). Severe cases can require hospitalization due to bodily inflammation that leads to tissue and brain damage. The Department of Health is encouraging anyone with these symptoms to see a doctor as soon as possible.
But there is good news. The State of Hawaii and many local organizations are coming together quickly to inform the community. Sara Routley, a Community Health Educator with the State of Hawaii, says that Maui County has had a huge response from organizations in the community. From the University of Hawaii to MISC, School Garden Programs to CTAHR, the Maui community is showing up in big numbers to organize responsibilities and inform residents about how to better protect themselves.
“We like going into the school because students are great family educators,” Routley said. “Not only can we educate the students on how they can better protect themselves, but students go into their homes and let their families know what they learned in school that day. We find that this is a great way to get information out into our more rural communities.”
I also spoke to Micah Munekata, an official with the state Department of Agriculture’s Plant Pest Control Department. Put simply, they see this as a much bigger issue than just rat lungworm disease. “We have a vast amount of invasive species and the inter-island bio security measures that we have in place are around pre-border, border and post-border measures,” he said.
The Department of Agriculture also issued a formal statement on what they’re doing:
One of the important measures that is still alive in the current legislative session which ends this week, is the creation of the Hawaii Invasive Species Authority through SB776. The establishment of the authority will expand upon the existing Hawaii invasive species council model by adding additional expertise to the interagency board of directors, authorizing the board to hire staff as necessary, and mandating new duties relating to the coordination of interagency invasive species and biosecurity efforts including data collection and management, support for rapid response to pests, and public resources for pest reporting and outreach. This particular measure was identified throughout the planning process of the Hawaii Interagency Biosecurity Plan as the #1 priority for all public and private stakeholders.
Munekata acknowledged that RLWD has been in Hawaii for some time, and will likely continue to exist here. “I don’t know if we’ll ever be able to stop the movement,” he said. “We are encouraging farmers to carry out the best management practices for clean growing spaces, a healthy farming environment and vectoring rats, slugs and snails from their properties.”
A DOA memo sent to the Hawaii Farmers Union and the Hawaii Farm Bureau reiterates safe practices and approved control measures of the slugs. These measures include using organic iron phosphate pesticides and state-registered pesticides.
It’s also important to remember that there’s no cure for RLWD. If you feel that you or someone you know has been infected, early diagnosis and treatment is crucial. In an average case, anti-parasite medication and steroids will be administered to decrease inflammation and attempt to move the parasite out of your body. But the tricky thing is that anti-parasite medication can also cause inflammation as a side-effect. Since the parasite is in the brain, the goal is to avoid further inflammation that will damage the brain.
In serious cases, medical procedures will be administered pending specific symptoms. But medical research and practice in terms of aiding in infection is limited in the State of Hawaii. Although doctors and medical professionals at UH Hilo are learning more on a case-by-case basis, most of the research and medical practices are based off treatments that have been used on rat lungworm victims in China, Taiwan and Thailand.
* * *
HOW TO PROTECT YOURSELF
- Always wear shoes and gloves in the garden and outside areas of your home.
- Wash your hands!
- Watch out for your children and animals in outside areas.
- If you find semi slugs around your property–notify MISC. Never use your hands to pick them up. Use “labeled” tongs and put them in a bucket of three parts water and one part Hawaiian salt for more than 72 hours to kill the parasite.
- Do not cut/break the heads off of greens and lettuces. Take each leaf off individually so you do not cut into a keiki/adult semi slug.
- Thoroughly wash all produce (vegetables and fruit) with running water. Take your time. Wear seeing eye glasses if you need them. Running water is the key here. No soaking. You are not just washing to clean off traces of slug trails, you are also looking for baby slugs, sometimes as small as a grain of rice or two millimeters in length.
- Do not use vinegar to wash produce! There is no scientific proof that vinegar, hydrogen peroxide, salt water, grapefruit seed extract or ice baths kill the parasite. In fact, it’s believed that these substances can create an aggressive response to a semi-slug–introducing more of the parasite. Just use clean water and rinse twice.
- The parasite dies if it’s frozen for more 48 hours. You can freeze your fresh produce for two days and alleviate any chance of becoming infected.
- When cooking, the parasite dies at 165 degrees Fahrenheit. Boiling point is 212 degrees Fahrenheit.
- Keep all food covered indoors and outdoors.
- Be cautious when eating raw and undercooked produce from potlucks and restaurants. Do not eat in places where the food preparer is not aware of RLWD and ways to properly handle food to avoid infection. Do not be afraid to ask servers and restaurant employees if they are aware of RLWD. In fact, MISC suggests that you ask them twice.
- If you’re buying plants and trees, inspect for semi-slugs, snails and frogs. You do not want to be moving an invasive and infected species from one part of the island to the next and into your home.
- If you’re buying produce from a local farm for a restaurant or your home kitchen, ask what that farm is doing to vector their property for rats, slugs and snails. If you do not feel that they are taking active measures to protect their clients, find one that is.
* * *
For more information about rat lungworm disease and invasive species, visit MISC at Mauiinvasive.org, CTAHR at Ctahr.hawaii.edu/site, DOH at Health.hawaii.gov/maui, DOA at Hdoa.hawaii.gov and DLNR at Dlnr.hawaii.gov.
Also, on Monday, May 8, the County of Maui will hold another community meeting on rat lungworm disease, this time at the Lahaina Civic Center Social Hall (1840 Honoapi`ilani Hwy., Lahaina). Doors open at 5pm, and the meeting starts at 5:30pm.
* This story originally misidentified the source of this information. MauiTime regrets the error.
Cover illustration: Matthew Agcolicol
Cover design: Darris Hurst