Heres the story of how I volunteered to be infected with 50 parasitic worms (hookworm) for a year as part of a research study. Check out this thread & follow me for more #parasite & marine biology content [t]
1st some background on the parasites I got. Hookworms are blood-feeding nematodes that live in the intestine of mammals including cats, dogs & humans. ~500 million people are infected with hookworm, mostly in tropical and subtropical areas including the southern USA
Infection with many worms (100+) can cause anemia, which is most problematic in kids, pregnant women, and the elderly. This clinical study was launched to try to develop a vaccine against hookworms to prevent infection
People become infected when baby worms living in the soil penetrate their skin. Baby worms hatch from eggs that infected people poop out. Where plumbing is scarce, poor waste disposal is a common source of heavy infections (100s to 1,000s of worms)
I volunteered to be vaccinated with an experimental hookworm vaccine (I was also paid). After vaccination, the vaccine (or placebo idk) was tested by infecting me with 50 hookworms (Necator americanus) that penetrated my skin from a patch of gauze I wore on my wrist for 1 hour
Within minutes I felt a tingling sensation under the patch. The baby worms were penetrating my skin! The worms sense fatty acids in my skin and release proteolytic enzymes to make it easier to slip between my skin cells and into my blood vessels.
Seconds later my wrist got VERY itchy. I have to seriously fight the urge to scratch as the itching continued for ~30 mins before fading. Here is what my arm looked as soon as the patch was taken off an hour later
I know the biology of these parasites & wasn’t worried for my health at any time. I asked for the worms to be put on my wrist so I could cover the resulting rash with a wrist band 😂 The study team did detailed blood work each week to ensure I wasn’t having any negative effects
Over the next week the rash from the worms & my immune response enlarged. The itch was more intense than any I’ve experienced - worse than poison ivy. I slept with Benadryl cream next to my bed b/c the itching rash would wake me up in the middle of the night. Steroid cream helped
At this point the baby worms were through my skin & riding around my circulatory system like a tube slide at a water park. At least that’s how I pictured them. This was during COVID lockdown – I appreciated the company & started using the royal “we” 🤣 The rash begins to fade
Blood works shows I have eosinophilia as my immune system kicks into high alert for parasites. After 10 days the rash returns with a vengeance! This was expected. Most infected people have an initial rash that fades, then it returns even worse before fading over the next month
Its not fully understood why this happens, probably a delayed immune response since at this point, the worms have long been gone from my skin. Its interesting how much the rash has spread tho. I suspect some worms got lost while looking for a vein and migrated around my wrist
After riding through my circulatory system, the worms were carried by my blood flow to my lungs. They break out of the capillary bed and into my alveoli and lungs. The worms still need to get to my intestine, but how? 🤔
The worms crawl up my throat of course! At this stage the worms are still only a few millimeters long so I never felt a thing. Some people report a cough but I only remembered coughing twice over these weeks (I had to write all symptoms down on cards for the clinical study)
Then I started giving a fecal sample to the study team so they could check my poop for worm eggs. The # of eggs in my fecal sample would let them estimate the number of worms I had. Every 2 weeks I pooped in a plastic container they gave me & dropped it off at the GWU MFA
I stopped being comfortable going into the MFA while they were seeing only research and COVID patients, so a doc from the study team made weekly house calls to my apartment to take my vitals, a blood sample, and pick up a poop sample. What service! 😂
70 days post infection and no eggs in my poop. Most people shed eggs after 50-60 days post infection with the patch. I began to worry. Had my worms died? What a sad 2020 ending…
Then on day 76 – the study team finds eggs in my poop! They find eggs by PCR & an egg float technique, which is just what it sounds like: put some poo in a saltwater solution, microscopic hookworm eggs will float to the top, skim off the top and check under a 🔬
My worms are alive – & MATING apparently! I’m oddly relieved. My worms dying off before even hitting puberty would’ve been a letdown. At this time the worms are in my intestine about this big (see pic) & using their teeth to cut my intestine & drink my blood. I notice nothing
At this point I’m shedding eggs at a rate of ~16 eggs per gram of poop (yes I asked the researchers for details). Google tells me a human poop weighs about 1lb or ~450 grams. That’s 7,000 eggs per poo! My worms are busy!
I feel normal but for 1 thing… no seasonal allergies! I have a scratchy throat in the spring from pollen but not this year! The worms secrete compounds to modulate your immune system slightly so they don’t get killed by it…
It’s been suggested this immunomodulation might help people w/ overactive immune issues like IBS, Crohn’s disease, or even allergies. The jury is still out on this and obviously my experience is just a single anecdotal one, but interesting!
After about 6 months with worms, it was time for their stay (and my part in this clinical study) to end. Fortunately, it is pretty easy to cure hookworm as long as you aren’t being continually infected
Normally you (or your pet) would be given a single dose of the drug Albendazole to cure a hookworm infection. To be EXTRA sure in this study, I was given 3 doses for 3 days in a row. A month after that, I gave a final stool sample, which did not contain any eggs
After nearly a year my journey with this study had ended. I still don’t know if I was part of the vaccine or placebo group, but I will follow up with the researchers to find out once the study is unblinded. I know I either got the placebo or the vaccine wasn’t 100% effective
It was really interesting to experience science/research from the other side – as a study participant rather than a researcher. I got to take my background as a scientist to this side of the experiment and ask questions each week to the nurse/doc I talked to. I learned a lot!
These days we have so many medicines, treatments, and vaccines that make our lives so much easier -- it's easy to overlook all the work and self-sacrifice that goes into making them safe and effective. I got to witness that here and I won’t take that for granted
I figured this would be an interesting study to be a part of & a fun story to tell for the rest of my life, and it did not disappoint! The only negative was the itchiness at 1st (although pooping in a plastic container every 2 weeks wasn’t exactly a welcome part of my routine)
Feel free to comment and ask questions and I will do my best to answer. Give me a follow for more parasite and marine biology content. My favorite parasites are crustaceans called copepods! I’m also on Instagram @jimmybernot

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More from @JimmyBernot

25 Jan
WHY STUDY #PARASITES?👇Imagine if your whole world was another animal 🤯 Follow me to learn more about these fascinating creatures 🤓
For more great #parasite content, check out some of my favorite parasitologists on Twitter:
and the American Society of Parasitologists: @AmSocParasit
And @WCPreisser too! Im sure I missed others. Creating a list of Parasite Peeps now. Suggestions welcome
Read 4 tweets
24 Dec 20
TANTULOCARIDA: FEMALES AND MALES BECOME PREGNANT WITH CLONES OF THEMSELVES! Saving 1 of my favorite crustaceans for the last days of #Crustmas [a thread]. Among the smallest arthropods, tantulocarids are parasites of other micro-crustaceans
All imgs:…
Here you can see a male “pregnant” with a sexual adult stage of ITSELF in its abdomen! Hard to wrap your mind around how weird the life cycle of these animals is 🤯 [t/n]
In fact the life cycle is even crazier than that! The tantulus larva infects a small host crustacean (copepod, cumacean, or other). Then the tantulus becomes “pregnant” with dozens of cloned tantulus larvae (bottom) OR pregnant with adult sexual stages (male or female, top)
Read 8 tweets

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