rat lungworm disease

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About This Disease

Angiostrongyliasis, also known as rat lungworm, is a disease that is reported to affect the brain and spinal cord, though anyone who has gone through the disease knows it impacts much more than just that. It is caused by a parasitic nematode (roundworm parasite) called Angiostrongylus cantonensis. The adult form of A. cantonensis is only found in rodents. However, infected rodents can pass larvae of the worm in their feces. Snails, slugs, and certain other animals (including freshwater shrimp, land crabs, and frogs) can become infected by ingesting this larvae; these are considered intermediate hosts. Humans can become infected with A. cantonensis if they eat (intentionally or otherwise) a raw or undercooked infected intermediate host, thereby ingesting the parasite.

A radio interview with Kaye Howe on Rat Lungworm Disease

life cycle

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juvenile parmarion martensi
Juvenile Parmarion Martensi on a nickel (Photo Credit: HDOH)

Veronicella cubensis (Photo Credit: Rob Cowie, UH Manoa)

Achatina fulica (Photo Credit: Jaynee Kim, Bishop Museum)

Signs and Symptoms
This infection can cause a rare type of meningitis (eosinophilic meningitis). The challenging part of this disease is that there is a wide spectrum as far as symptoms and severity which we are still working to understand the full scope of. Some infected people don’t have any symptoms or only have mild symptoms; in some other infected people the symptoms can be much more severe, and long-lasting.

When symptoms are first present, they most typically include severe headache and stiffness of the neck, light-sensitivity, tingling or painful feelings in the skin or extremities, low-grade fever, nausea, and vomiting. Sometimes, a temporary paralysis of the face or other parts of the body may also be present, as well as light sensitivity. The symptoms usually start 1 to 3 weeks after exposure to the parasite, but have been known to range anywhere from 1 day to as long as 6 months after exposure. Symptoms last anywhere between just weeks to many years depending on the level of severity- though on the CDC website it still says symptoms typically last between 2-8 weeks. In Hawaii we are finding more and more people who have been dealing with side-effects for months or years after infection.

You can get angiostrongyliasis by eating food contaminated by the larval stage of A. cantonensis worms. In Hawaii, these larval worms can be found in raw or undercooked snails or slugs. Sometimes people can become infected by eating raw produce that contains a small infected snail or slug, or part of one. Often found in raw salads, kale, or produce hiding in small crevices or curls of leaves. It is not known for certain whether the slime left by infected snails and slugs are able to cause infection. Angiostrongyliasis is not spread person-to-person.

Diagnosing angiostrongyliasis can be difficult, as there are no readily available blood tests. Getting a spinal tap is the best way to know for certain. Because many do not do a CST there are fewer cases recorded in the State of Hawaii then there actually are. Cases can be diagnosed with a polymerase chain reaction (PCR) test, performed by the State Laboratories Division, that detects A. cantonensis DNA in patients’ cerebrospinal fluid (CSF) or other tissue. However, more frequently diagnosis is based on a patient’s exposure history (such as if they have history of travel to areas where the parasite is known to be found or history of ingestion of raw or undercooked snails, slugs, or other animals known to carry the parasite) and their clinical signs and symptoms consistent with angiostrongyliasis as well as laboratory finding of eosinophils (a special type of white blood cell) in their CSF which shows up as high in cases of Rat lung worm. There is no reliable diagnostic test available to detect previous infections of angiostrongyliasis.

There is no specific treatment for the disease. While the CDC website states tht "The parasites cannot mature or reproduce in humans and will die eventually" there have been findings on the contrary of those with low immune systems having young parasites mature, grow and live longer than previously understood in the human body. In Western Medicine they simply give pain medications to relieve the symptoms, and some patients are treated with steroids. Anti-parasitic drugs are still being researched for effectiveness. If you think you have Ratlungworm contact your heath care provider right away and request a spinal tap and blood work.

Alternative naturalpathic medicine and Chinese medicine has been shown to be effective in supporting recovery.

Many people have reported long-term side effects from neurological damage to pain which can be supported through Chinese and Naturopathic medicine - you can read some of the treatments that survivors have reported to be supportive in Kaye Howe's case study of her son's illness here

Being infected with angiostrongyliasis does not protect you against becoming infected again in the future from another exposure to A. cantonensis.

Always wash and inspect all raw produce VERY WELL

1. Carefully inspect and wash and all fruits and vegetables under running water, especially leafy greens, in order to remove any tiny slugs or snails, regardless of whether the produce came from a local retailer, farmers’ market or backyard garden.

2. Wash fruit before peeling or cutting it. Even if the fruit has a rind you won’t be eating, like pineapple, it should be scrubbed before being sliced so there’s no chance of contamination as the knife passes through the rind or peel into the edible flesh.

3. Store all food and drinks in sealed containers to prevent contamination.

4. Cook your produce. Heating veggies to at least 165 degrees Fahrenheit for a minimum of 15 minutes will kill any parasites.

5. Control snail, slug and rat populations—especially around home gardens—to curtail the spread of rat lungworm disease. Make sure to follow label instructions when using bait, and keep pets and children away.

6. Gardeners, farmers, food handlers and processors should increase diligence in controlling slugs, snails and rats on the farm and in processing/packaging facilities.

7. Don’t drink from the garden hose. Tiny slugs and snails can crawl into the hose opening and be swallowed.

8. Supervise children playing outside, especially while on the ground. Watch what they put into their mouths and make sure they aren’t accidentally eating slugs, snails or other pests.

9. Scrub hands, nails and forearms after playing or working outdoors.

10. Cover water catchment tanks to make absolutely sure slugs and snails cannot get in.

11. Don’t eat raw or undercooked snails or slugs, and if you handle snails or slugs, be sure to wear gloves and wash your hands. Eating raw or undercooked freshwater shrimp, land crabs and frogs may also result in infection. Boil snails, freshwater prawns, crabs, and frogs for at least 3–5 minutes.

Preparing Foods - Pay Attention

To avoid ingestion of a slug or slug slime look closely (put on your glasses if you wear them) and thoroughly wash all vegetables and fruit under running water and remove and properly dispose of any parts of the fruit or vegetable that seems questionable.

Take more time with curly leafy vegetables and wash leaves individually. People advise soaking vegetables in grapefruit seed extract, hydrogen peroxide, salt water, etc., but there has been no research that supports that any of these will kill the parasite.

Avoid bringing slugs into your home with locally grown produce. Check pineapple tops or twist tops off just above the leaf base and leave outside.

Flatworms prey on the semi-slug and it is suspected that they may carry even higher loads of the parasites. They can easily hide in leaves or tight heads of produce and their soft bodies fall apart into small pieces when handled or under water pressure.

Cooking food will kill the parasite however the exact time/temperature has not been scientifically determined. Err on the side of caution. Of course this is not an option when it comes to certain fruits and vegetables depending on their intended use.

Take a little extra time to inspect and wash all foods to be eaten raw in salad or as part of a dessert or beverage. Avoid eating any raw fruit or vegetable while dining out where you cannot ascertain proper food cleaning prior to preparation.

Safe eating is healthy eating, but wash your veggies?

According to expert Dr. Susan Jarvi:

"This kind of education is no doubt very, very, important. But this problem is bigger than that. That's very, very good advice. But washing your veggies with water does not make them safe, it makes them safer. These larvae, these rat lungworm organisms, live in water. We've had them in our lab, in the infectious stage, after three weeks growing just in water."

"We now have a culture that when you give them a little food and after four months we can keep these guys alive. So, just washing your vegetables in water – especially in an area where you have such high, widespread, unregulated catchment use - where a lot of people do not have fresh potable water to wash their vegetables in, that is a very big problem."

"We also need research on catchment systems to find the best design for catchment systems, to try to block the larvae from entering into household water supplies as well as agricultural water supplies. We know people can get infected by ingesting contaminated water. Here in Hawai'i we've lost a baby – at least one child – and there's no way this baby could have gotten rat lungworm other than in the bathtub. So, the water issue is a really big issue and we need to have research on that as well."

"We've seen very well-maintained catchment tanks, but if you remove the cover, you'll find dozens of slugs in there," Jarvi says.

Many Puna residents drink catchment water which is run through filtration systems. Jarvi's group has gotten a $35,000 Karassic Family Foundation grant to test those filters. They have found that the larvae pass easily through 20 micron filters, which many homes have. They've just begun testing 5 micron filters. Those, and 1 micron filters, should be fine enough to keep the parasites out — 'theoretically.'

"These larvae can bore, and we don't know that the larvae can't go around the filter,” Jarvi says. "We just don't know."

She thinks a larger study is needed to determine how catchment systems overall can be designed to better prevent rat lungworm. But that study would cost about $600,000.

Completing the diagnostics expansion study — which is developing the blood test that that diagnosed Kana Covington — would take another $150,000 to $200,000. To finish the vegetable wash study, Jarvi believes, would require another $60,000 or so. Another crucial study would be a bio-assay to determine whether rat lungworm larvae are actually dead, and not simply paralyzed or dormant from a treatment — which would require yet another $15,000.

All this is very expensive and yet funding has been extremely slow or non-existent. When the Hawaiian legislature finally did pass legislation directing one million dollars towards Rat Lungworm almost none of it went to Dr. Jarvi and her research.

Additional Information Resources (Will open new browser window - close new window to return here)

Hawai‘i Journal of Medicine & Public Health - A Journal of Asia Pacific Medicine & Public Health
A General Overview of Rat Lungworm Disease

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Angiostrongyliasis (Rat Lungworm Disease): Viewpoints from Hawai‘i Island
Kathleen Howe and Susan I. Jarvi*
Department of Pharmaceutical Sciences
Daniel K. Inouye College of Pharmacy
University of Hawai‘i at Hilo
Hilo, Hawai‘i 96720, United States

Reducing Rat Lungworm Disease in Hawai'i Through a Collaborative Partnership With K-12 School Garden and Agriculture Projects
Kathleen Howe, Jenny Bach, Myles DeCoito, Shari Frias, Rebecca Hatch and Susan Jarvi
Department of Pharmaceutical Sciences
Daniel K. Inouye College of Pharmacy
University of Hawai‘i at Hilo
Hilo, Hawai‘i 96720, United States https://www.frontiersin.org/articles/10.3389/fpubh.2018.00203/full

Detection of Angiostrongylus cantonensis in the Blood and Peripheral Tissues of Wild Hawaiian Rats (Rattus rattus) by a Quantitative PCR (qPCR) Assay
Susan I. Jarvi, William C. Pitt, Margaret E. Farias, Laura Shiels, Michael G. Severino, Kathleen M. Howe, Steven H. Jacquier, Aaron B. Shiels, Karis K. Amano, Blaine C. Luiz, Daisy E. Maher, Maureen L. Allison, Zachariah C. Holtquist, Neil T. Scheibelhut. Department of Pharmaceutical Sciences
Daniel K. Inouye College of Pharmacy
University of Hawai‘i at Hilo
Hilo, Hawai‘i 96720, United States

Angiostrongylus cantonensis and Rat Lungworm Disease in Brazil

Pathways for Transmission of Angiostrongyliasis and the Risk of Disease Associated with Them

National Institutes of Health Library of Medicine Rat Lungworm articles search page https://www.ncbi.nlm.nih.gov/pmc/?term=rat+lungworm+disease

This information is not meant to be used for self-diagnosis or as a substitute for consultation with a health care provider. If you have any questions about the parasites described above or think that you may have a parasitic infection, consult a health care provider.

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