Beware the rat lungworm

Just a heads up.  This asian parasitic worm has arrived on the U. S. mainland and is now documented throughout Florida, and also in Alabama,  Louisiana,  Texas,  and Tennessee. No doubt it was spread much further throughout the southeast,  but hasn't yet been searched out and documented.  It's been present in Hawaii and Australia for a couple of decades.

Its normal host are rodents where it doesn't usually cause any problems, but when it gets into a non-rodent host, then there are problems. In humans, it causes a type of meningitis with symptoms including severe headache, stiff neck, fever, nausea, vomiting,  paralysis, and has the potential to be lethal.  Intermediate hosts for this parasite include slugs, snails,  frogs,  and freshwater shrimp. If you accidentally or deliberately eat one of these raw or undercooked, then you can pick up the parasite.  In Australia, a teenager who ate a slug on a dare fell into a coma for over a year, then awoke from it totally paralyzed and died 8 years later.  Most cases aren't this severe, but the potential is there.  Most infestations cause headaches, fever,  nausea, which first appear a couple of weeks after exposure and can last for several months. It also causes problems in dogs, horses, birds, and has killed a couple of primates at the Miami zoo.  

Our main potential exposure is in the home vegetable garden where there is the possibility of missing a slug when washing lettuce or other raw greens for salads, especially those with savoyed or frilly leaves. In asian traditional cooking, all greens are cooked, probably for this reason.

Fortunately in my garden, the asian needle ant has arrived which, in addition to wiping out fire ants in locations where the needle ants are present, has also been killing those small gray garden slugs whose populations have crashed since the arrival of the ant.

We live with rat lungworm parasites here in Hawaii. While the vast majority of people only get mild or even zero noticeable symptoms, the parasite is devastating to those who get full blown symptoms.

So what do I do on my own homestead as precautions?
... Nothing is nibbled on out of the garden while I'm working. I used to nibble peas, beans, ground cherries, cherry tomatoes, and greens while I worked, rather than stopping for lunch. I no longer do that.
... Anythng with visible slug slime gets chucked into the slop-n-glop cook pot, where it gets cooked for the livestock, thus killing any parasite eggs. Slime is extremely difficult to wash off, even with soap. So I don't chance it handling something with slug slime. All veggies and fruits are inspected when I pick them.
... I aggressively go after slugs. After I discovered that they eat lots and lots of slugs, I let feral turkeys cruise through the gardens. I never had good control using slug traps, only catching a few. A few isn't enough since I find dozens every evening with a flashlight. So I set up slug feeding stations and go out between 7-8 pm with a flashlight and scoop up dozens of slugs into a jar, which then goes into the freezer to kill the slugs. Once I have enough for a potful, I cook the little buggers and feed them to the chickens for sadistic revenge.
... I built elavated mini greenhouses for growing veggies I wish to eat raw, such as lettuce, radishes, carrots. The legs sit on bowls of salt, effectively repelling slugs. When the bowls accumulate water, I switch them with new bowls, allowing the wet bowls to dry out under a sheet of glass. Thus I recycle the salt. I tried copper wire, but the acidic air here quickly corroded it to the point that it wasn't working anymore. I find the bowls of salt simpler to maintain.
... I am switching to non-circulating hydroponics for growing Chinese greens and lettuce, again on slug protected platforms.
... I have gradually changed to cooking more things and eating less raw foods. No more raw green beans, snap peas, broccoli, cauliflower, etc.
... I carefully wash fruits and veggies when harvested, checking for slime and slugs.
... I no longer bite my finger nails. One habit broken.....all I needed was a good incentive!

How about fruits, I love to eat those right off the shrub with no washing. How do you handle those?

S Benji, I don't eat them without close inspection. Even so, eating them fresh is taking a risk. Slime trails are not always easy to see. While slugs tend to stay close to the ground, I have found them 4 foot up the side of a banana tree. And my hubby feeds the outdoor cats on the front porch (which is up on 2' high piers) on the porch railing, about 3' high. It's not uncommon to find slugs in the cat food dish in the morning.

I've been allowing my chickens and ducks free range through my vegetable garden and the rest of the property for years, only fencing them out of the beds growing crops that they like to eat. They also don't have access to the inside of the hoophouses.  The fenced beds are only 2 to 3 feet wide and 30 feet long so the pests they can't reach have only a short distance to travel to become chicken food.  I was doing this to control, crickets, grasshoppers,  earwigs,  sowbugs, squash bugs, and any of the other usual garden pests, but now with the lungworm likely present, slug control (our acidic soil means we have very few snails) takes a much higher precedence than it used to.

Fortunately the needle ants moved in about the same time as the likely lungworm presence.  They can access all parts of the garden including the fenced beds and the hoop houses and have been very effective at crashing the slug populations,  almost eliminating the small grey slugs from the outdoor beds.  There is a larger 3 inch long yellowish  slug whose numbers have increased somewhat this summer, no doubt due to the removal of its grey competition.  It's too large for the needle ants to take on, but I'm not seeing any of its babies around, so the ants are likely eating its eggs and/or hatchlings, so the numbers of this slug should diminish as the large adults die off or get eaten.  In the hoophouses, the needle ants cleaned out all of the fire ant colonies that were previously in residence and are providing good slug control. This time of year when the needle ants are mostly inactive due to the winter temperatures, my slug surveys are turning up mostly new hatched grey slugs less than 1/4 inch long and very few adults, these all likely have hatched since the ants went dormant and should disappear in spring when the become active again.  Slugs are active at lower temperatures than the ants.

I've stopped growing savoyed and other frilly leaved greens that are harder to wash and provide lots of hiding places for slugs to lurk.  Also eating fewer raw vegetables than I used to and stopped drinking from garden hoses.

I've been wondering what effect the lungworm presence is having on the wild animal population, especially those that commonly feed on slugs or frogs.  I've read where in Australia they've been following the spread of the lungworm by monitoring its effects on the native wildlife, namely birds and possums.  Also, since it is found in freshwater shrimp and freshwater crabs, is it also in crayfish (freshwater lobsters), in which case the raccoon population is at risk.

...
Slugs and rats carrying parasites.
Nightmare fuel.
As my local gets hotter and wetter,  I imagine we will just get more of this sort of thing.
Well,  if the chooks will eat the slugs,  I'll cook their eggs,  so no transmission there.
The threat from eating raw fruit or greens is another thing altogether .
Safe raw nibbles is supposed to be one of the luxuries we gain from growing our own foods!
Or maybe it isn't, and I  just want it to be.

Sooo... What does this mean for those of us who pretend that one day... we'll eat us some escargot? Is cooking them make it for safe human consumption?

Cooking kills the parasite and makes snails and frogs safe to eat.  That is why cooked greens don't carry the lungworm risk.

I am very interested in this as well.  We're the family that did catch and cook a pound of Texas garden snails.  Tasted like mild clam.  If my niece ever wants to repeat her experiment,  I would like to know it remains safe.

Joylynn --- Cooking kills the parasite, though simple blanching or quick steaming isn't long enough duration. Cooking snails makes them safe to eat. Freezing for 24 hours also kills the parasite, though large snails take more than a day to be frozen solid throughout. The recommendation is to freeze snails for 3 days if they will be eaten raw or undercooked.

William --- While rats carry rat lungworm, they can't infect humans. There presence needs to be controlled so that they do not pass the parasite to slugs and snails. As for your chickens, there's no problem there. People can't get rat lungworm from chickens. Even raw eggs are safe from this parasite.
   The raw fruits and veggies are a different issue. Unless they are carefully inspected, it would be possible to accidently consume a tiny neonate slug or snail without knowing it. The slime trail does contain a low number of parasites, but it not deemed to be as dangerous as eating the slug/snail itself. Consuming slime should be avoided. Nothing really washes the slime away. Getting it off my hands involves using gasoline!!! It has been shown that soap, vinegar, bleach, saltwater, and hydrogen peroxide are not effective washes. So much for safely washing it away.

So these worms enter my blood stream, then head to my brain, then kill me.
I hope there is a yearly bloodtest and if positive a yearly 'dewormer' for these critters.

It seems way too easy for my romaine lettuce from Florida or California to be contaminated. No more greek salad or burgers for me then. Just meat and grains and if I must have greens it will be in soup.

So this critter is form Asia how have the people there been surviving with them. The people there have a life expectancy of 70+ yrs. A bit lower than USA but not by alot. I just don't see them washing there fruits/hands/etc more than us.

S Benji, catching this parasite is apparently easy and common. But by far, most people show no symptoms. Some people have some, like headaches and flu-like symptoms. It's only the occasional person has severe symptoms. There is some thought that it is related to the number of parasites consumed. Eating the infected raw snail, slug, shrimp, etc itself results in a massive number of parasites. Consuming slime has only a few parasites. People are probably exposed via slime all the time, but few show signs of the parasite.

There is a blood test to determine if you have been exposed to rat lungworms. But it is only used if the parasite is suspected. Since most people test lightly positive even though reporting no symptoms, an annual test wouldn't make any difference.

Some frightened people have gone to using a dewormer on themselves if they fear they have possibly eaten a slug. I have been told they are using ivermectin but I don't know how frequently. In fact, I don't think the researchers even know how often and at what frequency the treatment needs to be done to be effective in preventing symptoms of rat lungworm.

Considering the vast number of people throughout the US who are consuming Florida and California lettuce and getting no rat lungworms symptoms, I'd venture to say that it's not a problem at the moment.

As for Asia, I don't know other than to say my Chinese/Taiwanese friends don't eat raw greens. Everything is cooked.

By the way, it is thought that dried slug slime is not infective. The parasite dies when dried out.

It's a nematode (roundworm), so ivermectin will kill it.

 In the southeast, only Florida has done a thorough survey for its presence by sampling rodents.  They found it present in every single county in the state.  In other states its has only been detected by people coming getting sick from it. In Louisiana, it was some guy eating a live treefrog.

In the life cycle of this parasite, the adult worms (2 cm long) live in the pulmonary artery of rodents in the lungs. Eggs are released into the lungs, are passed up to the pharynx, then swallowed and pass out in the feces.  The eggs hatch into larvae that eaten or can penetrate (like hookworm larvae) the intermediate host (slug, snail, etc.) which is then eaten by the final host.  In a rodent it passes into the bloodstream in the intestines, moves to the brain where it matures into its adult form, then moves to the pulmonary artery where it mates and spends the rest of its life.  In a non-rodent host it moves to the brain and eventually dies after a month or two.  It gets about 12 mm long while it is in the brain.  It is closely related to the canine heartworm which also lives in the bloodstream.

Mike, great information.

This is going to sound weird, but it will be calming people's fears in my area knowing that all of Florida has the rat lungworm. If Floridians are living with it without it dominating the national news, then things can't be so horrendously bad. I've been to a couple of small health department info meetings here where the officials are scaring the sh*t out of us for eating fresh fruits, and for handling anything outdoors without constantly washing our hands. Personally I thought the health official's info was a bit extreme considering the parasite has been present here for years. Being cautious and sensible is one thing, being paranoid is another.

Maybe some Florida gardeners can chime in, but I'm wondering how much of a problem slugs and snails are in Florida vegetable gardens. When I was living there in the 60's and 70's in Orlando, I don't recall seeing very many slugs or snails except for the apple snails in the rivers.  I wasn't  vegetable gardening, but was studying botany and visited a lot of different plant communities.  The sharp sandy soil isn't conducive for their travels, the predatory rosy wolf snail is native there, the hot summers aren't favorable for their activities (I've read that some of native slug species are fairly inactive during the summer).  The common grey garden slugs that are so common throughout much of the eastern US aren't found in Florida because they can't tolerate the hot summers there.

This young man ate a slug on a dare causing his death:

 So Australian teenager Sam Ballard grabbed the slimy creature and gulped it down. He had no idea that the slug carried a potentially deadly worm that would put him into a coma that lasted more than a year, paralyze his body and ultimately take his life.

Soon, however, doctors told them otherwise. Sam had developed rat lungworm disease from the infected slug, changing his life forever.

Soon after the diagnosis, Sam fell into a coma, where he remained for 420 days, Ballard said in the Australian news report. He woke up paralyzed, unable to eat without a tube or move without intense effort. He required 24-hour care, seven days a week.  

https://www.cnn.com/2018/11/05/health/man-dies-after-eating-slug-on-dare/index.html

It's a nematode (roundworm), so ivermectin will kill it.

I had to check out this drug https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3043740/

Discovered in the late-1970s, the pioneering drug ivermectin, a dihydro derivative of avermectin—originating solely from a single microorganism isolated at the Kitasato Intitute, Tokyo, Japan from Japanese soil