This time, out of the five small jars I prepared, four were almost entirely vacant of larvae — but one was hopping. Naturally, that’s the one I harvested from. I used 25 larvae, my usual dose.

I’m including photos of the site reaction: one from Day Four, when it looked the worst, and another from Day 24, when it was almost healed. I remember recovery being a lot quicker in the past, but I guess I’m getting older. Sorry if the Day Four photo offends — it does look bad — but honestly, there was never more than a light tickle in the first couple of days and never any real pain. I sent the Day Four picture to ChatGPT, and my agent freaked out, urging me to seek immediate medical attention. It cares — it really cares.

The work-in-progress video on the incubation process is coming along. I’ve got all the shots I need, though the quality was only so-so, so I might have to redo them with a bit more care. I’m also still refining the information I want to present. I signed up with Kapwing for video editing, and it takes time to learn. So, the video is coming — best guess: about another month, since I’ve got a lot going on these days.

And hey… don’t say I didn’t warn you about that photo.

Of course our conversation turned to hookworms and celiac disease as well as my other condition, ulcerative colitis. ChatGPT5 had an awful lot to say on the topic and was able to summarize past research for me and tell me where future research is going. Here's an example of one of our conversations:

Me: Earlier I asked you about why I have had such a good response with hookworms putting my ulcerative colitis and celiac disease into remission. Can you bring that information up again for me?

ChatGPT said: Of course, Pete — here’s the recap of what we explored earlier about why hookworms (Necator americanus) may have put your ulcerative colitis and celiac disease into remission:

🌱 The Hygiene Hypothesis

Modern life in highly sanitized environments may deprive our immune system of the “training” it evolved with. Helminths (like hookworms) were once common in humans; without them, immune systems may overreact to harmless things, leading to autoimmune and inflammatory diseases.

🧬 Immune System Modulation

Hookworms secrete proteins and molecules that dampen inflammation. They can shift the immune response away from aggressive, damaging pathways (like Th1 and Th17 cells, which drive colitis and celiac inflammation). They promote regulatory T cells (Tregs), which calm the immune system and help restore balance.

🔗 Gut Barrier & Microbiome Effects

Hookworms may strengthen the gut barrier, reducing “leaky gut” phenomena that can worsen autoimmunity. They also influence the gut microbiome, encouraging a more tolerant, less inflammatory environment.

⚖️ Why It Worked for You

In celiac disease, the immune system attacks gluten proteins. By calming your immune response and boosting tolerance, hookworms likely reduced or eliminated that reaction. In ulcerative colitis, chronic inflammation of the colon is the problem. Hookworm-induced immune modulation may have quieted the overreaction and allowed remission. Not everyone responds as dramatically, but your case fits the “super-responder” profile seen in some trials and reports.

✅ In short: Hookworms likely created a more tolerant, balanced immune environment in your gut — calming the hyperactive responses that once caused violent gluten reactions and severe ulcerative colitis flares.

Would you like me to also summarize what current research says about personalized helminth therapy (tailoring parasite type/dose to each individual), since you had such a strong positive response?

You said:

yes

ChatGPT said: Here’s a focused, research-backed look at what “personalized” helminth therapy could mean—and where the science is today—especially relevant to Necator americanus and your UC/Celiac story.

What “personalized helminth therapy” would tune

Species & product

Live worms vs. worm-derived molecules (secreted proteins/peptides) that mimic the immunoregulation without infection. There’s active work to identify and standardize these molecules for future precision use. PMC+2ScienceDirect+2

Dose & worm burden

Trials in celiac disease typically used 20–40 infective L3 hookworm larvae, with stepwise gluten challenges to test tolerance; responses vary by person. Newer work even measures gut worm burden (e.g., capsule endoscopy) to calibrate dose. PubMed+2Nature+2

Timing & schedule

Induction vs. maintenance dosing and how quickly to escalate exposure to the trigger (e.g., gluten) are key personalization knobs explored in hookworm–celiac studies. Nature

Patient biology & biomarkers

Baseline immune tone (Th1/Th17 overactivity), capacity to induce Tregs/IL-10, genetics (e.g., HLA-DQ2/8 in celiac), microbiome composition, and even “trained immunity” features likely influence who responds. Several 2024–2025 reviews argue future protocols should stratify patients by these markers. eLife+1

Disease context

Evidence is mixed across conditions: IBD and celiac have mechanistic plausibility and some positive signals; TSO (pig whipworm) meta-analyses in IBD show inconsistent efficacy, underlining the need to match organism/approach to the disease biology—not one-size-fits-all. PMC

What the clinical literature has shown so far

Hookworm–celiac trials: Multiple studies (including RCTs) show that controlled N. americanus infection can shift gluten immunity toward tolerance in some participants and permit limited gluten exposure with fewer symptoms—though not universally, and not yet as a standard therapy. PubMed+3PLOS+3ScienceDirect+3

IBD (UC/Crohn’s): Signals of benefit exist, but larger controlled data are still limited; a 2024 clinical paper and recent reviews reinforce the promise + heterogeneity theme (responders vs. non-responders). Oxford Academic+1

TSO in IBD: safety generally acceptable, efficacy mixed/neutral in pooled analyses—again arguing for tighter patient selection and endpoints. PMC

Why personalization matters (the mechanistic angle)

Helminths tend to:

Up-regulate regulatory pathways (Tregs, IL-10, TGF-β),

Down-modulate pro-inflammatory Th1/Th17,

Reshape the microbiome and strengthen barrier function.
But the magnitude of these effects varies person-to-person, so matching the right species/dose/timing to the right immune and microbiome baseline is likely the difference between a dramatic remission (like yours) and a flat result. Frontiers+2PMC+2

Where the field seems headed

From worms to defined molecules: Intense work is identifying helminth-derived proteins and glycans that reproduce the “tolerance” effect—more controllable, doseable, and potentially pairable with standard meds. Think of it as “helminth-inspired biologics.” PMC+1

Stratified trials: Reviews in 2024–2025 call for trials that pre-stratify by genetics, immune signatures, microbiome, and disease stage—i.e., genuine personalization rather than treating everyone the same. eLife

Objective monitoring: Tools to quantify worm burden and immunologic response (e.g., Treg/IL-10 assays, cytokine panels, microbiome metrics) will likely guide dosing and maintenance. Taylor & Francis Online

Practical takeaways for you (given your strong response)

Your history looks like a “responder phenotype”—meaning your immune system is highly amenable to helminth-driven regulation. In a personalized framework that would argue for:

Lowest effective burden that keeps symptoms in remission,

Periodic checks of iron status and general labs (hookworms can affect iron),

(If you ever switched to non-live options) interest in helminth-derived therapeutics once they’re available in trials.

If researchers were tailoring a protocol for someone like you, they’d likely characterize your baseline immune markers and microbiome to understand why you respond so well—and use that as a template for dosing/maintenance for you and others.

This time I'll be having a crack at making a video for YouTube showing the magic of how it's done. It'll be the first video I'll have ever made (home videos of hookworm larvae aside) so don't expect much, but I hope to make the process of hookworm egg incubation and larvae harvest transparent.

In case you are a new visitor to this blog, I use hookworms to treat my ulcerative colitis and celiac disease. I've been doing that since 2008 with great success with both conditions staying in remission as long as I have an active colony. I use 25 larvae every 5 months. I have observed that with me hookworms only last 6-6.5 months before dying off. And if I haven't reinoculated the colitis and celiac by then both conditions come roaring back, and I have go back on a highly restrictive diet removing both meat and gluten until my hookworm colony has been restored. The treatment is called Helminthic Therapy and globally there are 10s of thousands of people doing it. 

Figure on a couple weeks for the video.

Human hookworms (NA) don't reproduce in the body and since my immune system is constantly attacking them, I assume that attrition starts in earnest probably at the halfway point and by 5 months I might have between 10-18 left. This is strictly a guess but I think a reasonable one. I haven't noticed any GI symptoms at the 5 month mark, so that implies 10-18 functioning hookworm adults is all I need to stay healthy, but to stay that way for the duration I need to inoculate with 25 larvae. I'm obviously just spitballing here, but I'll continue to think this way until evidence to the contrary comes in. Everyone is different in terms of how many larvae they need to feel better and for how long. It all depends on the host's immune system and perhaps whether the person suffers from Inflammatory Bowel Disease. IBD sufferers tend to burn through hookworms faster than the general population.

Spidey guarding my microscope until the next incubation cycle.

https://www.youtube.com/@letshealIBD

Helminthic Therapy is used for Inflammatory Bowel Disease generally: celiac, ulcerative colitis, Crohn's. Kyla's videos contribute to the sharing of what anyone with IBD can expect if they go down the Helminthic Therapy route.

Seven days ago I set up 5 small jars for incubation. When I looked at them today 2 were barren of larvae, 2 were ok but a little sparse, and one was grade A. Having a good concentration of larvae makes the work of collecting them much easier. This time around all I needed were 20 drops or so on my Petri dish to find all the necessary larvae. I pipetted them onto a bandage and was good to go. Or rather I would have been if I had practiced with the new bandage and gauze I had bought. Turned out the transparent, waterproof bandage I had chosen was awkward to use. Frustrating when things don't go as planned and you have 25 hungry larvae soaking in the gauze waiting for a home and you are fumbling with a badly designed bandage.

Also, wrapping my arm with a stretch bandage with one hand wasn't easy. Larvae are dangerous in the sense if one got in your eye it could cause a lot of trouble. The process of application needs to be smooth and predictable and I failed in that this time. Eventually I got it right and I'm sure everything is fine, but I'm going to practice the hell out of the process for next time to avoid a repetition of today's fiasco. Even after a year of doing this I'm still learning.

Other than last month's fast-induced GI troubles things have been fine. My intestines appear to be ticking along, and I can't remember any reactions to food since I last wrote in this blog. I've been avoiding nuts and mayo as a matter of course. Actually, I'm not sure if I wrote about how in January I tried walnuts, thinking they were the most innocuous of nuts. Nope, they made me bleed, so as far as I'm concerned all nuts are verboten whether I've tried a specific type of nut or not. I like chocolate, so I've taken to making sure that any chocolate bar I buy is nut-free.

I've been talking up Helminthic Therapy with any doctor or nurse I run into on my travels. Most had ever heard of the concept before. I've reached out to the local Celiac and Crohn's and Colitis groups offering to do presentations but I've never gotten a response. Skepticism abounds on this topic, even among the people who would be helped most by it.

It's very close to what I do, except I wet the stool to make sure it doesn't harden and I use 5 jars at time since experience has taught me that some jars will be barren.

This time I used 5 jars. Three had zero larvae, one had an ok yield, and the last had good/very good population. The included pic is from that last jar. With that kind of density, collecting the needed number of larvae is quick work. 

This experience reinforces to me the necessity of using multiple jars. Five seems to be the right number, again with explanation that some portions of the stool being sampled for the jars simply don't contain eggs.

A good summary of the topic with the low-down that more research is needed. In regard to celiac disease, the article says that while clinical studies haven't shown substantial results, self-treaters show consistent success (like me).

I've mentioned this before, but doing a gluten challenge at 20 days post inoculation for a hookworm/celiac trial is doomed to fail. Necator americanus doesn't mature into its adult form till at least 30 days, which incidentally is when I found I could tolerate gluten again after I lost my colony last time. For many people using NA, it takes much longer before they see changes to their gluten tolerance.

This time when I put samples under the microscope, four of the jars were barren, and one was an absolute 'A', a single drop from the jar having at least the 25 larvae I usually inoculate with.

I'll keep trying, but right now the theory that this is all about the egg deposition in the stool by the hookworm females appears to hold. If the stool sample hits a vein of deposited eggs, that jar will be successful, otherwise you'll get squat. I inoculate with 25 larvae. When people start out, they use considerably less, suggesting that their incubations will be less successful because there would be fewer hookworms laying eggs in the gut.

It is possible that there is some minor finesse causing jars to fail. Next time, I'll do my absolute best to make sure the jars are prepared as identically as possible.

My celiac disease and ulcerative colitis remain happily in remission, with my next inoculation due mid-January. The only recent weirdness is a new reactivity to mayo. I can eat eggs just fine, and I use oil in cooking, so what's up with that? According to Google (Healthline) - "Although the most common allergen in mayonnaise in egg, it's possible in rare cases to be allergic to some of the other ingredients, including: soybean oil, due to a soy allergy, especially if it's expeller pressed or cold pressed. lemon juice, due to a citrus allergy. vinegar, due to a sulfite allergy."

I'm becoming convinced this is truly all about the quantity of eggs in the stool. If the colony is having an off day and not releasing many eggs, resulting incubations will always fare poorly, simple as that. That means incubating will forever be something of a crap shoot, requiring multiple jars and allowances being made for complete failure. However, turn around time being only a week, there should always be enough time for additional incubation attempts before experiencing a hookworm gut die off.

This time I used a roll of Athletic Wrap Tape / Self Adhesive Elastic Bandage to keep the bandage attached to my arm while sleeping. It worked well.

I used 4 jars for the incubation this time around. Two large and two small. There was a very wide variation in the number of larvae the jars produced even though they were prepared the same way.

Small red - A+ - 10 to 15 active larvae per drop. An ideal result

Small green - F - I didn't see any larvae in any drops from this jar

Big red - B -  Enough for inoculation but it would mean work collecting 

Big Green - E -  Very few larvae, perhaps not enough for inoculation

Again, I don't get why there is so much variation. The set-up is simple. Add a small amount of water to a sealable jar, stuff a coffee filter lightly smeared with stool containing hookworm eggs. Make sure the filter paper hits the water so the larvae can climb down, and wait about 7 days. It doesn't get much easier than that. Going forward, I'll stick with four small jars. Maybe some day I'll figure out why all this is. At least next incubation, I won't have to worry about the heat being a factor.

As luck would have it, a day after I set up my jars, the temperature shot right back up again. I don't have A/C in my apartment, so I figured I had just wasted my time, but this morning when I checked one of the small jars I found things were hopping! In just a couple of drops there were all the larvae I would need, bopping and weaving, looking healthy as all heck. I didn't bother to check the three other jars, I'll report on them in another post when I do my inoculation tomorrow. 

I'm at a bit of a loss to explain this feast or famine behavior for yields. Best I can suggest is that people plan for this variability by allowing enough time so they don't get caught out. My last inoculation was 4/25/24, so I would expect the hookworms in my gut to start dying off roughly in the next 30–60 days. By inoculating tomorrow, I can be reasonably sure there will be no loss of immune modulation coverage and I get to keep eating my shredded wheat in the morning.

The only thing different this round was the heat. It's been consistently over 30C in my non-air conditioned apartment this week. Damn global warming!

Since I'm new at this hookworm incubation game, it's quite possible that what I'm seeing is a heat effect. I had planned on inoculating from this batch, but I do have plenty of time for up to three or four more tries before I run out of room. By September I would expect my existing gut buddies to start dying off. I'll use four jars next time. Fingers crossed.

The first of the large jars was ok, maybe a little light in larvae. The second large jar was BARREN! I think I saw one larva in my sample. The third, small jar was a surprise though, it was booming! Squirming larvae hanging from the chandeliers, partying like it was 1999. Huge numbers. We're talking 12 larvae in a 40X field of view! Previously I think the record was maybe 4, and that was searching around to get those 4. This time it was like there were crowds of larvae. First time in perhaps 12–13 jars I've had such an incredible result.

All three jars were prepared at the same time in the same way from the same stool sample. Looking at the jars now, I can't see any reason why one of the jars would have failed and one would have been so spectacularly successful. An admin in the HT group said this sort of thing is why most people do several jars at a time, and possibly it was due to an uneven distribution of eggs in the stool sample.

The first step is to purchase larvae from a provider listed in the Helminthic Therapy Wiki and when they arrive, slap them on your arm.

Afterwards to save money, if you are into DIY, several months later you can start to incubate to provide your own supply. Hookworms eggs will now be in your stool. A lot of them. The simplest method would be to smear infected poop on a stick and lean it in a bucket with water at the bottom. 

However, we can do a lot better than that. Hookworm larvae pose a threat and uncontrolled exposure would be dangerous. Initial inoculations these days are often recommended to be only 3 or 5 larvae so that the immune system can get used to their presence. You need to know exactly how many you are getting. To ensure control and safety of the incubation process, some refinements to the bucket concept are required.

The simplest and safest idea I've seen is to place a coffee filter smeared with a small amount of poop hung suspended above a small amount of water in a hermetically sealable jar. The filter should touch the water. These jars are tough to break and will keep odor in, as well as prevent the water from evaporating. Placed in the dark, 10 days later there should be 300-1000 L3 larvae sitting in water.

To harvest the larvae, you'll need a microscope to pipette drops from the jar water onto a slide or petri dish. From there you can either transfer larvae into another container for later use or directly wipe them onto a bandage for immediate application.

There are some techniques worth mentioning here. Safety is of utmost concern. The work surface must be covered with a plastic sheet (a garbage bag will do) and paper towel should be laid on it so you can see and deal with any spills. Plastic gloves must be worn, and pants and long sleeves aren't a bad idea (a lab coat would be ideal). I was pretty nervous my first couple of incubations and had some spills.

What I eventually realized is all I needed to was to crack open the jar and remove a mere milliliter or so of water via pipette and create a checkerboard pattern of very small drops on a petri dish. The drops should be about the width of the field of view of the microscope, which in my case is 1/2 a centimeter, or 5mm. Each drop will probably contain 0–3 larvae. If you are starting out, 3 larvae might be all you need. Wipe that drop or drops onto a bandage, apply it, and you are done.

Cleanup would involve pouring bleach into the jar, sealing it, and freezing for several days along with both it and any supplies that might have come into contact with larvae, including the petri dish, the pipette, the paper towels and the garbage bag. A large Ziplock bag is useful for this. Later, the jar's contents can be safely flushed and the other materials doubly bagged and tossed in the trash.

It wouldn't be a bad idea to practice the whole thing end to end a few times just using plain water until you've got the idea down.

Everything you need for incubation and inoculation is available on Amazon or AliExpress. I've skipped some details, like how much water to use in the jar, the amount of stool to use, and how to suspend the filter, pipette size, but those are just details. In this post, I just wanted to give the big picture.

The Helminthic Therapy Wiki has other incubation methods, and you can read about those here. In my experience, charcoal, vermiculite, incubators aren't necessary. Perhaps they lead to greater or more reliable yields for those folks, I don't know.

Before pursuing either inoculation or incubation, joining the Helminthic Therapy Support Group on Facebook is a must. Introduce yourself and mention what conditions you are attempting to treat. There's also a subgroup for those doing incubation. Giving the Wiki a solid read is important for you to understand what you are getting yourself into with Helminthic Therapy.

Here's a video of a particularly active larva. Let me know in the comments if the link isn't working.

This larva was from a recent incubation and examined at the 6-day mark. Between the two jars there were hundreds of larvae.

So not great, but if things don't work out this incubation I have time to do another, this time exercising more care.

Also, I think I'll take a sample each day under the scope to see when larvae start appearing. It's supposed to be 5 days at high room temps and 9–10 days and normal room temperature. Let's find out for sure. 

I'm doing fine. Still staying away from peanuts. No gut adversity to report.

Hookworms successful against colitis and celiac disease after medicine fails

⚭Home>Personal stories>Detailed stories>Hookworms successful against colitis and celiac disease after medicine fails

I currently inoculate with 25 Necator americanus larvae every 5 months to keep myself in remission from celiac disease and ulcerative colitis. This works very well for me. If I let my colony die off/age out both conditions quickly return.

Ten years of misery in spite of medicine and dietary measures

My story of GI issues began when I was 35 when I started noticing that I was reacting to protein powder. The seller had never heard of a problem and I just chalked it up to a curious mystery. Sometimes I could tolerate it, other times I couldn’t.

Fast forward to age 42. I developed an abdominal abscess that eventually led to three surgeries and left a minor permanent disability. That experience was unpleasant, but what came next over the next several years made the abscess pale in comparison. I developed ulcerative colitis.

Initially it was blood in the bowl that got me to check it out, but rapidly came the pain. Treatment was mesalamine suppositories. I’ll never forget seeing a mountain of suppository boxes delivered to my door. What fun! So far as I know that medication did little to control my colitis. The situation soon became worse with intense bouts of diarrhea that eventually hit upwards of 11x a day. Between the disability, the ulcerative colitis and the diarrhea I had no quality of life. I became home bound and seriously considered suicide as I saw no way out.

After a couple of years of this I finally got wise and started doing elimination dieting. Two months later, I discovered the diarrhea was being caused by gluten. I immediately adopted a gluten-free diet and the diarrhea stopped the next day, however the damage was done. I still experienced a good six months of expelling buckets of blood and mucus, and it was a good two years before things really settled down.

The colitis was always still there, though. Over the years, it waxed and waned. Unfortunately, after 10 years, things really came to a head. I was down to about a dozen simple foods I considered least problematic. I lived on eggs, sardines, rice and potatoes. Nothing with an ingredient list, and no beef or pork as meat would cause an immediate colitis attack. The baseline colitis had strongly amped up and I considered having a colectomy. It was at that point I finally pulled the trigger on trying hookworms. The prospect of more surgery trumped fear of the unknown.

Hookworms bring relief from symptoms and pain

I had first heard of hookworms as a treatment for celiac disease back in 2010 but I didn’t know how to pursue it. Over the years I had read several more articles on the topic and in the summer of 2018 I finally pulled the trigger. I found a provider via Quora and ordered some. Back in those days there was less control on initial quantities. The max was 25 and that’s what I asked for.

They arrived late July and I inoculated immediately, but because I was so nervous, it took me till early December before I finally did a gluten test. I had no gluten in the house, so I borrowed a piece of bread from a friend. I tried the smallest pinch I could and waited with bated breath as my gluten reactions were extremely severe. There was nothing. By the next day I was back on a regular gluten containing diet. After 12 years, I was free! It was a miracle.

I had no issues until the first week of March the following year. I had thought hookworms lived for several years, a decade even. Maybe so, but the symptom relief turned out to last only 5–6 months for me, post inoculation. Through later experimentation, I determined that it was about 30 days after inoculation that I was able to handle gluten.

And that’s where things stand now. I am symptom and pain free with no dietary restrictions. Hookworms have been a huge success for me. I just have to make sure my inoculations come on schedule. I do use a hydrocortisone cream post inoculation as I do develop a strong skin reaction, but I never experienced any side effects from the hookworms.

For some time now I've maintained a blog where I describe my hookworm journey and promote hookworm use by celiacs. It’s my strong opinion that anyone diagnosed with either celiac disease or ulcerative colitis should be treated with hookworms as a matter of course and it’s almost malpractice if they aren’t. In my case drugs, a gluten-free diet, even a meat free diet didn’t make me healthy. It took hookworms for that, and I regret all the years of quality living I lost because I wasn’t hosting hookworms.

Over the winter I plan to try my hand at breeding my own supply of hookworms to both lower the cost and to ensure a ready supply.

By Pete Dixon, August 2023.

Even with top and below lighting and a sample where I knew there was a larva directly in the center of the drop, I still couldn't see it. I could sort of make out other debris, but no, just no.

It's still a cute tool, though. You plug into your computer's USB port and using an app like VLC you can project a live image to the monitor, which in my case is a 55" TV. It's fine for looking at features on coins and the like, but my dream of a portable kit that I could take with me travelling is a bust. The only suitable tool for hookworm larvae harvesting is a full-on microscope. I particularly like my dissecting scope with ample room for pipette work.

For this test, I was looking at the contents of another two practice jars. It was early, only 5 days in, and I saw only a few larvae. Enough for my 10 larvae needs, but nothing like I saw before. I'll check the jars again at the 10-day point.

Ted Simon uses an incubator and vermiculite. His channel offers several other hookworm related videos, including one where he shows using a microscope to harvest the larvae.

My method doesn't use an incubator or vermiculite and I get good results, but I can't claim consistency as I don't have that much of a track record yet.

The first jar's water probably had about 100 larvae total, the second had substantially more, in the order of 200-300. This estimate is based on how much water was in each jar and how much water I pipetted out of each into a petri dish and scanned. In the second jar that I launched 2 days after the first, I placed more stool onto the coffee filter. More stool = more eggs = more larvae. Collecting larvae from the first jar would have been more work as the larval density in the water would be less and more time would be required to find them. To put this into context, from the first jar several mls of water sometimes wouldn't have any larvae at all. In contrast, from the second jar several times I had 5 larvae in the microscope's field of view at once (@ 40X that's only 5mm, or a small drop). The latter makes for easy work.

So from the two jars my yield was 300–400 larvae. On my current program, I only need 10 larvae every two months. In other words, an ample supply 

I did try the trick of placing jar water in a wine glass in the hope that the larvae would settle to the bottom, but I really didn't see much of a difference.  

Going forward, I'll keep doing two jars and increase the stool on the filter. I'll reinforce the thread supporting the filter to ensure the extra weight doesn't collapse the filter into the water. Maturation of the eggs into larvae is heavily influenced by temperature (90°F means 5 days, 68°F would take 9-10 days). I'll be taking that into account for the next incubation.

Scuttlebutt on the HT Discord server is that sometimes incubations fail for no obvious reason. Perhaps the hookworms in the gut take a rest and don't produce eggs, or perhaps they get stunned by antibiotics taken by the host, or by food that was eaten the hookworms were sensitive to. For that reason, I think it makes sense to have two jars going at once as insurance, preferably launched several days apart.

Incubation has turned out to be both simpler and easier than I expected. There's really very little effort once you get the hang of it, and the cost saving is substantial.