My opportunities for observing scabies were extensive. In the Confederate Army. Our soldiers were badly fed, badly clothed, soap was scarce, and army itch, as it was denominated, was painfully plenty. Army itch is nothing more than scabies with exzema or impetago, or ecthema or some other dermatosis superadded. In eighteen sixty two, in the Confederate Service, I became the subject of Sarcopti's hominus. At the same time, several generals and some very elegant
ladies of my acquaintance were my fellow sufferers. At first, the itching was not only not unpleasant, but was positively delightful. Very soon, however, the proitis became terrific. I often awoke at night, exhausted and panting from violent scratching begun in my sleep. I lacerated the skin with my nails to abate the tortured itching, for the smarting pain of the upbraded surface was far preferable to the proitis. Sulfur ointment relieved me entirely in three days.
The only difference I can discover between the army itch and scabies as it is met with in civil practice is a difference in degree. Soldiers frequently neglect to apply for treatment until they are completely covered with the eruption, and in such cases it is sometimes so marked by lacerations made by the patient's nails and by secondary eruptions
that it would be difficult to recognize the disease. It is not surprising that the disease should cover a larger extent of the surface and appear upon the outside of the limbs as well as in the flexures. When we consider the crowded manner in which soldiers live in their tents or barracks, and the carelessness that exists among them in regard to personal cleanliness. That was a little harsh, isn't it.
It is a little harsh. So those were quotes from the American Civil War about scabies, which was apparently very endemic, very prevalent throughout both armies, throughout the towns where the armies passed through, and those quotes themselves were from a couple of places. One the first one was from the book The Itch Scabies by Errol Craig, and the second was from an article by Cropley from two thousand and six titled the army itch a dermatological mystery of the American Civil War.
Mystery was it was? It was it?
I think the mystery was concluded to be like it was skabyab It was definitely scaly, really bad scabies, and like probably combined with just the general grossness.
That accompanied everything. I can only imagine.
I mean, I feel like I remember quotes from our typhoid episode and it was just like pooping near water sources and stuff like that. Pooping and holes was our very first episode. Yeah, but probably applies. It was also, Yes, scabies was also prevalent during World War One.
Blah blah words.
You know that's jumping ahead of things.
Hi, I'm Aaron Welsh and I'm Aaron Alman Updike.
And this is this podcast will kill you.
If you haven't guessed it. We're talking about scabies. It's all just skabes today.
Gabies, scabies. I am really excited for this because we haven't done something like this in quite a while.
It feels I mean, you know how when we were doing Neurovirus, you were like, I was so nauseous recording this episode. I have never been so itchy. Really. I actually did have lice and it really made me feel like I was like, do I do I have Lisay, I'm like I I was so so so, like I'm surprised that I don't have wounds from how much I was scratching. My last reading about Scutty's, I did not feel that itchy.
And I don't know why.
I don't know. Maybe because the.
History, I mean, but there were like a lot of excerpts about the itchiness. I guess maybe I didn't read as much about like the these widespread outbreaks, but people certainly talked a lot about the the itch and also like how enjoyable. Like that's something that I found really strange, is that, like that's not the first firsthand when I was talking about how enjoyable it was to itch or to scratch the itch. Yeah, that's not the only time I encountered that sentiment.
How interesting.
And then somebody else was like anyone who actually had scabies probably does not agree with this, and.
Like so that's like just what doctors would say about it back then. But like, yeah, I don't know, I mean, maybe I do.
I will say that when I had really bad poison ivy, that first hit of the hot water from the shower head and it would just it, It would scratch it in such a delightful way, but then it would lead to uncontrollable itching. Yeah. Yeah, so maybe I can relate anyway, Speaking of itching and scratching, it's quarantiny time, It's quarantin any time. What are we drinking this week?
We're drinking the itch Itch.
The itch is. You know this episode is coming out early Decement. I feel like it's nice cozy times, so we're doing a cozy drink to hopefully soothe any sort of itchy feeling or to have it is. Essentially, it's like gingerbread vibes, is what we're going for us. We've got rye whiskey, We've got a little bit of orange juice, a little bit of ginger ale, and then like a spiced syrup with molasses and spices.
It's going to be so yummy and cozy so that you can cuddle up by the fire and scratch your itches. You can find the full recipe for that quarantine as well as our non alcoholic plusy Burta on our website, this podcast witha dot com, and on all of our socials. Are you following us there? Because you should be following us on social media.
You should on our website, you can find all sorts of things, from transcripts to the sources for each and every one of our episodes. You can find links to bloodmobile, to bookshop dot org, affiliate account, to our Goodreads list, to merch to Patreon, to promo code. So if you ever hear about something on the podcast where you're like, oh, what was that thing that you just advertised for, go to our website try to check it out and other things that exist there. I'm sure it's.
Great, And if you haven't already, please rate, review, and subscribe on your podcaster to this podcast because it helps other people find it and we love it and appreciate it. So thank you so much, thank you, thank you, thank you. On to a topic of today, great love it. We'll take a quick break and then talk about the biology of scabies. I have to just start this way because it was one of those moments of you know, when you see something in one place and then you can't
stop seeing it everywhere. Yeah, we just recorded our episode on strep pyogenies and scarlet fever. So ready for this, I'm ready. The first paper I read about scabies. It was a review in The Lancet from two thousand and six. It was a great paper. They start off, literally start off the paper saying, I'm going to quote here quote. Scabies is a neglected parasitic disease that is a major
public health problem in many resource poor regions. It causes substantial morbidity from secondary infections and post infective complications such as acute post streptococcle glomeriolonephritis. Oh g, I know, and now everyone knows that is. It's when your kidneys get attacked by your own self after a strep infection, which is a major complication of scabies infection. So let's get into it, shall we. Yeah, okay, but like.
Why is it just because strap is one of is on many people all the time.
Yeah, it's because impetigo, which is the main superficial skin infection caused by strep, is the main risk factor for post strip glomery leonephritis, and scabies is a major risk factor for a whole bunch of like secondary skin infections. But skin infections are mostly caused by either staff or strap. And so if it's strip, then you get this. Oh
my goodness, it's terrible, let's get into it. Yeah, so scabies is an infection of your skin, but it's an infection of your skin not with a bacteria, not with a virus, but with a mite called Sarcopdi's SCABYI variant hominus. And I feel like people might not know what the heck a mite is. So a mite is an arachnid, which means it's more closely related to spiders and ticks than like mosquitoes or other insects. But I feel like when you look at pictures of especially these particular mites,
they look more like tartar grades like water bears ampletely do. Yeah, they're kind of cute.
Yeah, maybe not as cute as like a lause, but pretty cute.
Yeah, I don't know. I kind of feel like they're cuter than a laus but your around, judge. So they have this like little head. You can barely even see that they have a head. They kind of just have these little chompy mouth parts, and then this really big, fat, chunky body with these little rolls of like toddler legs that don't look like they should be able to touch the ground. And then they have little hairs coming off of them. Yeah, and I don't know. They're kind of cute.
But when I say that, they're right now, right, especially.
All of the like generated images that aren't like real pictures of them under a microscope.
They're really like the face app what's it called.
Yeah, one of the Instagram face filters put it.
Yeah, they've got Once you put filter on the mite, it is it is much cuter than the laus. I take back my earlier claim. They do have a lot of spikes on them.
They have a lot of little hairs. Yeah, but this.
One, oh, that must be computer generated. Yeah, it's like on the skin. It's very cute.
And I'm like, oh, right, it looks like a little teddy bear, like a toddler. They're very cute. Anyways, they're also incredibly tiny and aarin you asked before we recorded, can you see these mites? And that paper that two thousand and six review paper in The Lancet described them as quote at the limit of human visibility. And of course every paper sites how big they are. But I have a real hard time conceptualizing how tiny something is when you give me a number. So here is your concept,
Aaron of how small they are? Ready?
Okay, great.
Size twelve font. We all know that size, right did you know that that size? Like font sizes are based on measurement, and size twelve font is a unit of measure called a pika. I learned a lot on Wikipedia. It's just over four millimeters. That's how big size twelve font is. These mites are size one font.
I'm not sure what you mean by twelve, Like, what do you mean.
If you typed on a piece of paper and printed out size twelve font, Yeah, it would be four millimeters each letter.
Oh, each letter would be four millimeters.
Got yeah, okay, yeah, so mites are if you type into your computer and change it to size one font, that's how big a mite is.
So okay, But like like an H or like a C, or like a period or a specific of questions? Yeah, like I mean, because an H is very different than a period, So like what so.
Not a period? Like a letter? Like a letter, like a like a typical letter in a in size one font. Type it into your computer. You can see it if point four millimeters and there's a range, so maybe like an M or a H. I don't know, there's a range and the males are half that size. So the males are even tinier.
Okay, I'm doing it with a t because that was the first one that came up. There, you go one. I can't see it, Yeah, I do, man, I can see it exactly.
I wrote the word scabies in size twelve and then I wrote it in size one next to each other, just to keep that in my mind for this whole episode. So they are very very very very small. Point four millimeters is the average size for a female mite, and the female mites are the ones who actually cause disease. So these mites, Sarkopdi's scabyi variant hominus, is a human
specific mite. There are a lot of different mites in the same genus sarcop Di's that cause disease in other animals, and much like our friends the lice, they tend to be very species specific, so every species of animal has our own species of mites. We also have lots of other mites that live on us, called Dermodex mites, and these tend to not cause disease, but Sarcopti's sure does, and their life cycle goes a little something like this.
Adult males and females find each other on our skin, They mate and then the male dies and the female then burrows herself into our skin. And conveniently, we've talked about our skin layers relatively recently on our Retinoid's episode. So these mites are staying incredibly superficial only in that epidermal layer, so that very first layer of our skin, and even within those layers of the epidermis, they only go to like about the middle part of our epidermis,
So they're really superficial. But in order for something so tiny to burrow underneath our skin, they spit out an enzyme that essentially dissolves our skin cells, and then that's what they eat, So they feed on our dissolved skin goop.
Yeah, it's kind of like maggots in that way.
Sort of. Yeah, exactly, just really small and they're really efficient. They burrow pretty quickly. It takes them about thirty minutes to make their little nest. And in their little nest, in their burrow in our epidermis, they lay a whole bunch of eggs.
How much is a whole bunch?
I knew you were going to ask, so we'll do some air and math to tell you exactly they lay. Some sources say like one to three or two to four, so we'll call it an average of two eggs every day. And those eggs take like three or four days to hatch, and they live underneath our skin for about four to six weeks.
And after the eggs hatch.
They lay two eggs a day every day for four to six weeks. Oh I see yeah, yekay, So that's about if you call it an average of two eggs a day for an average of five weeks, it's about seventy or so eggs that eat each female might is depositing.
And then at the end of that four to six weeks they're just like peace out. Okay, yep, they die they okay. A few questions here, give it to me. When they hatch, where do they hang out there? Do they have to find their own burrow? Do they just go down the skin a bit?
Like?
What what's going on?
Great question? So when they hatch there, of course like larvae or they call them like protonymphs. So they have to eat our skin goop and then molt and grow two more times before they become adults. And then they will go out onto the surface of our skin and find a mate of their own. And that process takes a couple of weeks, so like ten to fourteen days to go from hatched egg to adult, and in theory, they could do this on your body or on another human body if they're transferred to another host.
Because the female is laying eggs continuously for that chunk of time. This can be like a growing infection. It's not self limited, it can be.
But the average might burden is surprisingly only about five to fifteen mites per person, which is a lot lower than something like the LUs burden can be, and it's honestly a lot lower than I expected. A lot of this probably has to do with our immune response to the mites, and we'll get into that in a little
bit more detail. However, there is also a condition called crusted scabies, and in that situation, a person can be infected unfortunately with hundreds, if not thousands, of mites because they essentially can just grow and continue to grow unchecked by our immune system.
Okay ooh yeah, how does that. We'll get it to play into this, Okay, okay, yeah.
If there's any good news aside from the fact that most of the time the mite burden is relatively low, transmission also tends to require body contact and is not as much reliant on foemtes, so like bedding or clothing or things like that, which you might think of with things like body lice, it's a little bit easier to transmit that way. Yeah, they only live for a couple
of days max. Off of the body, but most of the time, because the mite burden is relatively low, there's not a lot of transmission that happens from things like bedding or clothing. It usually takes fifteen to twenty minutes of skin to skin contact for mite transmission to happen. Got it.
Yeah, and it has to be the female mite.
Yeah, it's the female mites that are causing the disease. That are the ones actually burrowing into our skin and causing disease.
What proportion of eggs are male and female?
I have no idea, What a fun question.
No clue. Can scabies? Sorry?
I love it. I love I can see on your face that you're just like I have so many questions I do.
Can scabies mites? Are they known to transmit any pathogens?
Excellent questions. No, not any pathogens to humans that we know of, thank you. Okay, So, as this might burrows into our skin. As I kind of alluded to, it really does kind of set off our immune system in a way that's really important. We heard in our first time to count just how itchy scabies can be, but I just said that the mite burden itself is usually
relatively low. And it turns out that the itchiness and the main symptoms that people get from a scaby's infection are actually caused by a hypersensitivity reaction to the mites, to the mites themselves, and to the feces, to the poop that the mites are leaving in their burrow, just like fleas, right, fleas can do that poison ivy. Arin, you mentioned the itch from poison ivy and how you like very specifically have like reactions to hot water and
things like that. This is the same type of hypersensitivity reaction, which also means that this itch is no not limited to the places where the mites are. The itch is everywhere. It's a generalized, incredibly itchiness because it's hypersensitivity reaction everywhere.
The mites themselves most often infect places like your wrists, the like interwebs between your fingers or toes, the areas underneath your waistband, armpits, groin places like that, places that are kind of like little areas that are easy for them to like nestle their way in. And sometimes you
can see the areas where scabies actually infest. And when you can see them, they're described as like this one little kind of nodule or vesicle, this one area where where the mite has actually made its burrow, and then a little curvy, very short, little curvy burrow that just looks like either a red or a dark or a gray or a purple kind of line. And then maybe a little vesicle in the place that the mite is
now living, like at the end of her barot. Okay, but most of the time you can't see that at all, and what you see instead are scratch marks all over a person's body from itching. You can see other like nodules that appear are other bumps that are all a part of your immune response to these mites and to all of the antigens that these mites are producing. And the itch tends to happen weeks after the initial infection.
It's not like right away unless you've been infected with mites before, in which case immediately will you feel itchy. As soon as that might makes her home.
Yeah that I mean, it makes sense, Yeah, it makes sense. It does because I had no idea weeks to mount an immune responses.
Yes, wild yeah yeah yeah.
Now there is another phenomenon I mentioned crusted scabies, and this is what happens when there are very large numbers
of mites that can establish an infection. But in this case, there's very often an association with some kind of immunodeficiency, whether that's HIV, whether it's topical or systemic steroid use, whether it's people who are on immunosuppressive medication because of an organ transplant, or maybe they are malnourished, lots of different potential reasons that you could end up with crusted scabies.
But these situations are very very severe because what happens is that there are so many mites that you end up with these severe plaques where the skin is growing, it becomes hyperkeratotic, which is that very thick, very scaly like flax and scales, and these can flake off and they harbor a lot of mites, which is why it's more easy for things like bedding or clothing to serve as a source of infection in these cases, got it, okay.
In all cases of scabies, there's a very high risk of secondary infection, which means everywhere that you're scratching and there's a break in the skin, it's really easy for bacteria like streptococcus and staphylococcus to get into those wounds and then cause either skin infections or especially in the cases of crusted scabies, more severe infections like bloodstream infections
and sepsis and even death. So scabies is kind of a big deal, especially because, as we'll talk about later, it's still really really prevalent.
There seems like there are many different options for treatment. There are what are those options and is there any are there like treatment resistant mites or scabies?
Yeah, there are so most of the treatment options, and there are a lot of different kinds. Most of them are topical, which means that there are lotions creams that you're putting on all over your body because again, you're not sure exactly where the mites are most of the time, so the treatment really has to go kind of everywhere. And there are things like permethrin that's what we use
most commonly here in the States. Benzyl benzoate is another one or sulfur compounds, and these are all generally very effective, but there are a number of different things that can contribute to either of them being difficult to implement, Like some of these require multiple applications multiple times a day for multiple days in a row, which can be sometimes difficult to do, and some of them can cause a lot of other skin reactions, like they can be itchy,
they can cause stinging and burning and be really uncomfortable to put on. Then there is also insecticide resistance, especially to things like permethrin. So yes, we do see some resistance, and this is something that can also be induced, like if you are repeatedly applying it, especially maybe not to all surfaces of your body things like that, then you can have resistance start to appear. But most of the time we still rely on topical treatments. There is an
oral treatment as well. Everyone's heard of it now, it's ivvermactin.
I knew you were.
Ivremectin is a phenomenal option. We've talked about it on this podcast before because we use it for a lot of other parasitic diseases, especially worms, that's what it's mainly used for. This tends to be used for things like crusted scabies, which requires both oral and topical treatment because
it's so severe. It also can be used as a second line if you treat someone with a topical and it doesn't seem to go away, or in areas where you have really, really high prevalence of scabies, then sometimes oral i'veremectin is used as what's called mass drug administration, so giving it to an entire community to try and really wipe out scabies. There's a couple of things that are important to know about scabies and the treatment for scabies.
First is that again sometimes people don't have symptoms of scabies for weeks because it takes weeks for that itch to first appear. But even after someone is treated, it can take weeks for their symptoms to get better. And that's again in part because so many of these symptoms are due to our immune response to the mite antigen. So these treatments are wiping out the mites, but they're
not necessarily treating the symptoms of the itch themselves. Okay, reinfection can also happen because, especially when we use topical treatments, mites can hide in some places like under the fingernails, and so That's why sometimes it's hard to know are the symptoms still there because the mites are still there or just because the symptoms haven't gotten better in a
couple of weeks. But usually if it's not better in a couple weeks, then you have to think is there a reinfection or was it not scabies to begin with?
Gotcha? So Aaron, Yeah, why why do we scratch? Why do we itch? Why do we scratch? Why do scratching relieve an itch?
Oh? I have no idea. I actually can't believe that's the first time that you've asked me that question. I know, like we've talked about itching before. I don't know what does it? What does it do? I mean, it's got to be releasing some like neurotransmitters, right, that are that are interacting with whatever the receptors are that are causing us to feel that itch. H Then scratching somehow does something to help relieve that. But I don't know. Yeah, and like what think interesting episode?
Yeah? Just itching?
Yeah?
I yeah, because like if if it's something that's immune mediated, something that's like driven by you know, like we we control that, our bodies control that? Is it adaptive?
Is right? Evolutionarily, and now I'm thinking, like what is the what.
Is the benefit out of an itch? I mean there's probably many different things, like if there's maybe if you feel a mosquito or something on your body.
I don't know, right, Oh, that's such an interesting question. I don't know, and I need to look into it. I didn't research itching, Aaron, which I had.
Well, just like it's you know, like how it is described as pleasurable at first, or like to scratch its preasurable at first, and like why does it feel good to have your back scratched, your arms scratch?
You know, like what Yeah, those head scratchers and head scratchers, those are Yeah, I don't know. What an interesting question, Aaron. We're gonna have to look into it.
Yeah, we will.
Okay, Well, but I would like to know, Yeah, where did these gabies come from? I mean, like, are you gonna answer that? I don't know. They're just with us.
I'm gonna answer something. Okay, let's take a quick break and we'll see what I talk about today. You can't define the word scabies without mentioning the might that causes the itch, and in that same vein, you can't describe that might sarcopti's scaby i hominus without including that it causes skin infestations in humans. The might and the itch are indivisible, entwined, inseparable, but that hasn't always been the case.
I love that. Aaron I was like, yeah, I'm feeling that that's not how it always was. You know.
I love a leading statement.
I love it.
For centuries, the itch and the might stood separately in the eyes of medicine, with no clear causal relationship between the two. And I call out medicine specifically because that's where the confusion remained about the cause of scabies until shockingly late in the history of medicine. Among the lay people, the peasants, the commoners. Stavies was well known for thousands of years to be caused by a creature, and that it was the creature moving from person to person that spread the itch.
I'm I love this story already. I am bought in.
When the night was finally widely recognized by medicine to cause the itch with a capital eye as it was kind of known. It was like scabies was known as the.
The itch, right. It was all the things that itch you, this was the one.
The one yep, capital I, and this recognition marked a huge turning point in the history of science and medicine. It called into question concepts like the humoral theory of disease or spontaneous generation where life just comes spontaneously out of the maggots on the meat in organic material exactly.
Yeah, yeah, which.
Both of which had been accepted as truth or at least had been leading causes of you know, explaining the world around us for hundreds, if not thousands of years. The recognition of the might causing scabies led to contentious rivalries with public humiliation, prize money, and medical demonstrations. It could even be argued that the might itch connection primed the scientific world to accept Louis Pester's germ theory of
disease in the following decades. Stop it eron, I know, would you have believed that this little might had this much up its little mighty sleeve. I certainly had no idea.
I love it.
But before we get into this might revolution as I am calling it, let's travel back to where it all began. But where and when that is we don't fully know. It's course surprise. One hypothesis suggests that humans and early human ancestors have been infected for millennia with this might,
and that other Sarcopti's scabyie varieties evolved from our human might. So, for instance, the might that causes one type of mange in dogs and other canids was thought to jump from humans to dogs after domestication, but another hypothesis suggests the opposite happened, that when we welcome dogs into our lives, we also welcomed a hitchhiking MTE that adapted to live on us and cause us to itch.
Okay, I don't know.
As far as I could tell, how humans and mights got acquainted with one another has yet to be fully resolved, and maybe it will be by the time we do our mange episode, which we will be doing at some point in the future. Don't worry, we did not. This is not mange erasure, this is not wombat might erasure. We're going to cover all of the wildlife animal mange scabies situations. Yeah, And as to the question of when people first described scabies the itch, it's also less than
fully resolved. So some people point towards a line in Leviticus in the Old Testament suggesting that the Hebrew term zarath, which meant some sort of skin malady, actually meant the itch or scapies, or was referring to that. Others say that it was the ancient Romans who distinguished scabies from other skin conditions, and in fact the term scabies comes from the Latin scaberry scabbery, meaning to scrape or to scratch.
Much later, the mite genus name Sarcopti's comes from the Greek word sarks for flesh and Coptian for to smite or cut. The ancient Romans also proposed what would have been and actually remains, as you mentioned, aaron an effective treatment for scabies, sulfur with liquid pitch. Others still say, nah,
the Romans got it wrong. It was actually an ancient China that the first true scabies description was made, And not only that, but unlike the Old Testament and ancient rom which just made note of the skin condition itself, the itch itself, this early medical text from China in the five hundred CE included mention of the parasite quote the itchy scaby sores always contain a tiny worm. We can extract it with a needle and see its worm like shape when it.
Is dropped into water end quote, Well, that's weird.
I think when we think of worm, we think of like earthworm, and I think that's not necessarily what because worm pops up a lot in descriptions.
Of scabies over the years, but does not I mean because the burrows are sometimes described as like surpiginous, which to me, I mean that's like snakelike. But I think of that as kind of wormy. But is a worm not always kind of like long and wiggly, I.
Mean, if it's so tiny, like can you even tell?
It's just like, oh, that's what That's why I think is weird. I mean, I mean because our other demodex mites are longer, their bodies are like great little kind of more tubular, tabular total, but these mites are just so round. I just but I don't know, maybe worms are different.
Also, this is translated so like I don't know if like worm, if that is the closest approximation too, yeah, yeah, yeah. Unfortunately, as is the case for so much of the history of medicine, information from the non Western world rarely makes it into reviews about this topic, and so it's really like, is you know, is the worm the closest approximation is
that the right translation. I don't really know whether that perception in terms of the worm causing the itch remained the predominant view, right like that's but we do have that text. In any case, in European medical writings, the mite wasn't really mentioned alongside scabies, like scabies was just itch, right, bitch. The itch was thought to be caused by what other than a humoral imbalance, imbalance and thus treated with all sorts of horrid little things like purges, foul smelling salves,
blood letting, and so on. Meanwhile, though in the non medical crowd, people knew what was up, like peasant women quote unquote knew that you could extract little bits from the skin to relieve the itch, a practice disregarded by medical men for being vulgar. A medical text from the eleventh century in the Middle East says, quote the little flesh worms which crawl under the skin of the hands, legs, and feet, and there raise pustules full of water, are
called sirones, as, sooa, bat and asa. So small are these animals that they can hardly be seen by the keenest.
Of vision and h I mean, I would agree with that, that's true, size one font.
Size one. Saint Hildegarde of Bingen do you remember her from our Migraines episodes? So she wrote about her visions, and some people have said that these were migraine aura, not actually like you know, or like aura inspired these visions, right right, right, So she wrote around the twelfth century that quote, there is another mint which is large. It
is hot rather than cold. This should be crushed and placed above and around the place where the seren or snevelzen are hurting the person with their nibbling, and they will die as the coldest of the same mentha major is rather bitter and therefore kills the above mentioned little worms, which are born in the human flesh end quote. So
the little spontaneous generation there a little bit of worms. Yeah, worms are a thing, Yeah, I guess so, yeah, it might just be like bugs, you know, like little critters.
Yeah, maybe that's what they mean by worms. Huh. Yeah. Interesting.
And these passages I think are really interesting because they show two things.
Right.
They show that people definitely observed the mites, even if they called them worms in association with the itch, right, But they didn't necessarily make the link that they caused the itch. Hmm, Like there's not necessarily a causal relationship.
Right there, then the itches there, but they're also like if you get rid of them, you'll feel better.
But also in some of these it seems like they're describing the miight as arising from the itch, if that makes sense, like a product of the itch.
Interesting. Yeah.
Over the next few centuries, a few passages here and there allude to the possibility that the might could be the cause of this itch, but they were overshadowed by the predominant belief that the might was not related to scabies, and that scabies was caused by a humoral imbalance. As to how it could be contagious, which it was recogne to be, that was explained simply by that the bad scabies humors contained in the blood could reach the skin and transfer it to other people.
That way, I got to love when you have an explanation for everything that just false.
It's honestly, it's pretty wid But the tide started to turn in the seventeenth century with two major advancements. Number one, the first known depiction of an infectious organism, and number two, the quote first comprehensive description of an infectious organism causing disease.
End quote scabies.
Scabies is the first one comprehensive description of an infectious organism causing disease scabies skate bees, according to this book and a few other things I've I've come across in papers.
Yeah, wow, yeah, I never knew that here.
I me either, I never suspected scabies. It kind of makes sense.
And though because they're bigger exactly, so they're easier. Like, yes, you still need a microscope to really see them. Well, but like if you have better eyes than me, maybe you can see them without or even just like a magnifying glass, which they had back then.
But like what about like lice and like, yeah, that's.
Fair, but I mean it sounds like scabies where it could feels like it could have been.
Either yeah exactly. Yeah, well okay. So in sixteen fifty seven, using an early microscope, physician August Houptmann published a description of the scabies mite, including an illustration a little oval, six legged, tiny thing with four long hook things coming out of its rear. It's very interesting drawing.
Two with only six legs. I mean, let me see if I can find a picture of this Aaron. Okay, oh, it's so cute. It's very cute. Yeah, it really doesn't look that much like a.
Very detailed, but it's it's stuck, a little thing shooting out of a I don't know, I.
Don't know what those are.
It's cute, though not perfect, but it was the second advancement that would really get things going. In sixteen eighty seven, Italian physician Giovanni Cossimo Bonimo, who was twenty four at the time, and scientist Diacento Cestoni, who was fifty wrote a letter to Francesco Reddy, a well known naturalist, and in this letter, Bonomo described how, while working as a physician on a ship carrying enslaved individuals, he saw men removing small little bits from each other's skin to help
relieve their itch. He also saw poor women picking out little pieces of material from their kid's skin using a needle. And what makes Bonomo's observations unique is not that he was the first physician to witness this practice and note it. It's that he thought there might be something more to it and actually followed it up with research. He enlisted the help of his father's colleague Sistoni, who had the
good fortune of possessing a microscope. Using this microscope, they examined the material that came from their patient's itchy skin and found mite after mite, even mites laying eggs. Like they watched mites laying eggs. Whoa, And they noted that these creatures behaved like insects, and they reproduced, they laid eggs, and they lived in burrows in the skin, causing the itch not coming to life because of the itch not there randomly. These mites, they hypothesized, were the direct cause
of the itch which had haunted and plagued humanity for millennia. Wow, they weren't the first to describe this though, right, Like, they literally watched people picking mites out of each other's skin.
Right, Everyone was like, well, yeah, dude, we knew this.
Get with the program, like welcome, welcome to the club. So I think in that it's not necessarily fair to say that they were the first to make this connection. But they were the first, in a scientific formalized setting, the first to describe this might, it's life cycle, its characteristics, and to link it to the itch that these mites caused.
How interesting arin right?
Yeah, And this makes it the first official description of an infectious disease and its causative agent. And again this is sixteen eighty seven, so well well before germ theory.
Right, way way way before.
Yeah, it's it's pretty cool. Yeah, but also, like, what the heck took so long?
Right? If everyone else knew it, why did it take.
So long for someone to actually note it down? Like, first for a scientist to write about this might itch causal relationship, and second for the scientific community to embrace it. Because even though Bonomo enlisted the help of a renowned naturalist in getting this observation out there, he was like, hey, can you, like, I'm going to release this pamphlet, can you you put your name on it and maybe write a few extra things, and then that'll help get a
wider distribution so people think it's legit. Yeah, people were like nah, it was largely rejected for another one hundred years. There are several reasons I think contributed to this, and the first one is practical. So, like you said, erin the mites burrow is not directly where the itchy sores tend to arise, a little bit farther away, so it's not as clear that the two would be linked.
Okay, fair, yeah, oh true.
But the other main reason is simply the conservative nature of science. For millennia, learned men discarded the wisdom of peasants or women or non learned folks in general as not scientifically valid without giving it due consideration, and this superiority prevented them and still does in some ways today from exploring ideas outside of the box. And science in general is pretty rigid when presented with new information that conflicts with established facts, which is not necessarily a bad thing.
Any new data, especially data that challenged the laws of nature, like the humoral theory of disease, should be checked and replicated and only then integrated into the body of knowledge. This is part of what makes science trustworthy, this need for a consensus. Of course, that's no excuse for closed mindedness and gatekeeping, which unfortunately are other hallmarks of science.
So the concept that a tiny bug caused this dreadful itch went against everything that scientists knew and learned about how diseases worked. Bonomo and Sistoni anticipated this rejection, and so this is why they had this ready lend his name to this pamphlet. But I want to read you a quote from this because I think it is well, it's just really it's interesting, okay.
Quote.
Having frequently observed that the poor women, when their children are troubled with the itch, do, with the point of a pin, pull out of the scabby skin little bladders of water and crack them like fleas upon their nails, and that the scabby slaves in the bangyo at Leghorn do often practice this mutual kindness upon one another. It came into my mind to examine what these bladders might
really be. I quickly found an itchy person, and asking him where he felt the greatest and most acute itching, he pointed to a great many little pustules not yet scabbed over, of which, picking out one with a very fine needle and squeezing from it a thin water, I
took out a very small white globule, scarcely discernible. Observing this with a microscope, I found it to be a very minute, living creature, in shape resembling a tortoise of whitish color, a little dark upon the back, with some thin and long hairs, of nimble motion, with six feet a sharp head with two little horns at the end of the snout end.
Quote, I love that a tortoise a little to I could see that.
Yeah, yeah, And they go on to describe how they looked at more mites, They talk about treatment and contagiousness, and they deliver this direct conclusion quote from this discovery. It may be no difficult matter to give a more rational account of the itch than authors have hitherto delivered us like, you can't do better than this, essentially.
Right, yeah.
It being very probable that this contagious disease owes its origin neither to the melancholy humor of Galen, nor the corrosive acid of Sylvius, nor the particular ferment of Van Helmont, nor the irritating salts in the serum or lympha of
the moderns. But it is no other than the continual biting of these animal cules in the skin, by means of which some portion of the serum oozing out through the small apertures of the cutess, little watery bladders are made, within which the insects, continuing to gnaw the infected, are forced to scratch, and by scratching, increase the mischief and thus renew the troublesome work, breaking not only the little pustules but the skin too, and some little blood vessels
and to making scabs, crusty saurs and such like filthy symptoms.
End quote. So I there are so many little pieces in that description that I loved, Aaron right, like, so so so many.
I just the the increase, the mischief, thus the.
Mischief, Like it's like they're little and they're biting there, like it just it's so many pieces of it, and it does make so much logical sense too, even though like they're technically a little bit wrong because it's like hypersensitivity reaction, but like it is such a logical It is such a logical description of what they saw and what is going on.
Yeah, And I love how they're like, it's not the humors, bro, it's not it's not that humor.
It's not the other humor you were thinking about. No, I already thought it, right, They're just like it's this, and like they keep going with it. They're not just like, yeah, there's a mite in the skin, clearly, They're like, no, dude, the mite is there and it's biting, and then it keeps biting and it makes a little pustul and then you itch at it and then you scratch it and then you push it in further, and then it keeps biting, and now you've broken the skin. Like they just they
they keep going and going. It's so good and.
It's all laid out there, so it's so straightforward that it must have been widely accepted and settled things once and for all.
Right, But no, of course, never, ever, ever, ever.
The resistance largely came in the form of, well, but the worms have nothing to do with the itch. They grew up out of the disease tissue, like you with maggat rotted meat.
Right, what a weird Like I know that we have to like take our modern brains out of this, but like, what a weird thing to think.
It's a hard it's harder to do when you're literally confronted with ample evidence of this, right exactly millennia, Yeah, I mean, but yeah, and those voices of resistance found out this well reasoned explanation for nearly one hundred years after this pamphlet was published.
Wow.
Eventually, though, with more interest in the might and the itch, the accepted knowledge began to shift, and a good number of these publications directly mentioned how they observed quote unquote like peasant and village elders extracting the might from the skin, saying that this knowledge has existed and has been passed down for a very long time, but it's only just now finding its way into the scientific literature, and it would take a final push to put the last shred
of doubt to rest. In the early eighteen hundreds, wow, I know. Right at the Hotel Saint Luis and Paris, which was a scabies hospital, two factions emerged about the cause of the condition. On the pro mite side was the director Jean Louis Alibert and on the other Francois Vincent Raspaio. Things came to a boil when a challenge was issued find the might and receive your reward, which was three hundred francs, or fail and live with your
shame forever. So Raspail set up a public demonstration this is the anti mite side, where he pretended to find the mite and was like, oh my gosh, it's actually here. This is incredible, and it was like, pich I planted it. It's just a cheese mite. So he had someone plant a cheese mite. Like too much time on your hands.
Oh my god, I just what I know?
Can you imagine it.
Also, I love imagining someone in the eighteen hundreds going, so.
This is like a public demonstration, Like, I want to know how well it was attended, was it advertised? Was he just like on just like randomly on the sidewalk on a Tuesday.
I also now want to know more about cheese mites.
So I agree, Okay, there's so many mites in the world.
What if it's how many mite?
And I guess. So that was the I suppose the humiliating moment for the pro mite side that was like, just kidding, it's a cheese mite.
I mean, it seems humiliating for him, but I wasn't there, so I don't know.
All right, no, let's see benefit of the doubt for the full scenario. But the pro miters would get the last laugh. In eighteen thirty four, when medical student Simon Francois Renucci was like, you know what, I'm I am going to find this, like I know that this that' scabies is caused by a mite, and I'm going to show everyone. And so he gathered a bunch of doctors together and was like, I'm doing this demonstration here, and he pulled a mite from a patient in front of
everyone and was like, here it is. I found it. It's a little bits in the borough, a little bit away. There's a great illustration of this historic moment with Renucci holding up the mite for all all to see, which just like cracks me up because I'm like, I can't see it in size one font but it's like triumphantly with his arm in the air and this demonstration this like I found the mic here, here it is in this person. I don't know how it took so long
for this to happen. Yeah, this was the start of a monumental shift away from the humoral theory of disease. And this isn't like, this isn't the thing that made people go, oh maybe we should question right, a combination of things, right. It sort of was like it was part of the transition away from that. The rest of the eighteen hundred saw Ferdinand rittervon Hebra, who I mentioned
in our Loopus episode. So he was an early scientific dermatologist, because like, I come across these names and I'm like, some familiar where are you coming from? And then I just like search our transcripts. He distinguished the might cause scabies from other itchy skin conditions which had been called scabies in the past, and that was probably part of what led to this like long confusion. It was just like if you're itgy, it's called scabies.
Right right right? It was the itch, but it it is the might yes, yeah.
And then this also helped on the treatment front to determine which ointments were or were not effective, and the early twentieth century marked a jump forward in our understanding of scaby's epidemiology. As you can imagine, scabies mites love a war, they love chaos, and World War Two, with its crowded barracks, offered a great opportunity for these little guys to infest to their hearts content and infest they did,
and they didn't just get under the soldier's skin. By the nineteen forties, between one and two million people in the British Isles had scabies. This was a problem in need of a serious solution, and Kenneth Mellanbie, who was a British entomologist, felt up to the task. So he directed a series of experiments where he exposed human quote
unquote volunteers who were primarily conscientious objectors. So this was like they refused to join the war effort, and so he proposed this as like, oh, show your service to the country in another way. Yeah, And it's interesting because I think there has been, of course some criticism of this,
you know, even with the ethics at the time. I do think it's relevant to note that he was morally opposed to experimentation on what he felt were not true volunteers, like people in prison or people who couldn't really say no, like children and so on. So that part is interesting to me. But I also don't know how much power conscientious objectors had to say no.
Yeah, I don't know enough.
I don't know the context enough for that. But in any case, he directed a series of experiments where he exposed these conscientious objectors to various items like blankets, towels, pants, shirts, socks, underwear that had been used by people infested with scabies, to see how long it would take to cause an infection.
For centuries, scabies had the reputation of being super duper contagious, like all you had to do to get it was touch a blanket used by a person with scabies, look at someone who had skabies, like it was just like whoa the most contagious thing. Ever, but Melanie's experiments showed
that this was not the case. He found it near impossible to get any of his volunteers infected, much to their relief, I imagine, And when they did get infected eventually, it took weeks for symptoms to show how which, as you mentioned, Aaron, yep, and it was much sooner though if you had had scabies before, so it'd be like six weeks or twenty four hours, right, that's it. Yeah, And he even tried it on himself.
Quote.
My own experience was typical. I allowed a mite to burrow into my own wrist and observed it almost like a pet, for two months. Each day the tunnel was enlarged, eggs were located in the burrow, but I had no skin reaction. It was only in the fifth week that a redness was observed around the might and that skin irritation became obvious quote interesting. He also found that scabies could only be transmitted by a female mite, not eggs, not immature mites, and that female mites don't live very
long out like outside of the human body. And this meant that the Ministry of Health could better spend their time and money, tracking down contacts of affected individuals and treating them rather than destroying or disinfecting blankets and bedding.
Oh my gosh, Yes, that's so good public.
Hell right resource management. Despite his work, the misconception of scabies as a super contagious condition remains to this day, and I think it contributes to the stigma that scabies carries with it. Scabies as a medical condition is extremely uncomfortable and can be dangerous in some occasions. But that's just one part of the story. For the hundreds of
millions of people around the globe that developed scabies every year. Shame, social isolation, avoidance, These are common experiences in people with scabies, and they can discourage a person from seeking treatment or informing other people about exposure. And while we have treatment that is for the most part effective, while we have control measures, we still need to really improve on actually putting those in place, which means decreasing the stigma associated
with scabies. And so on that note, Aaron, can you tell me where we are with scabies today?
I would love to right after this break. Globally, the World Health Organization estimates that at any given moment, two hundred million people worldwide are affected by scabies, with over four hundred million people affected cumulatively each year. It's like four hundred million cases each year. And it's everywhere. It is, everywhere that humans are, there is scabies. But even with all of that knowledge, our data is actually really cuddy, and there is a real need for better evaluation and
better monitoring. While scabies exist everywhere, it exists differently in different places across the globe. In most high income countries, we see it in sometimes in outbreaks in places like hospitals, nursing homes, among homeless populations, though it can also occur sporadically,
right like anybody can potentially get scabies. But in developing and underresourced areas of the world, both urban and rural areas, prevalence can sometimes be as high as ten percent, and in some regions, in some studies, prevalence has been as high as twenty to thirty percent and over fifty percent in children, who tend to be even more affected than adults.
So this is a huge, huge problem worldwide, not only because like we've talked about a lot so far, like this is a very potentially painful, very bothersome infection, super super itchy Also, the itching is much much worse at night, and that is something that I could not find data on as to like why does the itch? Why is the itch so much worse at night? But it is. But scabies is also a massive risk factor for things like secondary bacterial infections, and I mentioned it at the
very very top. But this causes also not just the infections themselves, but then morbidity and mortality from things that happen as a result of those infections. One paper estimated that up to ten percent of kids with scabies end up with renal damage, and that renal damage is not from the mites, it's from the bacterial infections that get in because of the mites. Right, Like, I had no idea that it was such a big deal me either. It's also really common to misdiagnosis in the US and
across the globe. In one paper, up to forty five percent of people in the US, even at dermatology offices, were misdiagnosed the first time that they came in and saw physician. Is what is a common misdiagnosis? It could be eczema, it could be just a topic dermatitis, it could be just any kind of nonspecific itchyness, got it lots of different things and also interesting and very depressing. Fact. Again, I just scaby's felt so much bigger to me than
I realized. The Global Burden of Disease study, which is this big study, I've cited it multiple times, they try and look at like overall burdens of a whole bunch of different diseases. So a report from twenty fifteen on scabies specifically estimated that scabies contributes more disability adjusted life years than something like atrial fibrillation, which is really common and most people have probably heard of it, so it
has a huge amount of disability associated with it. But this paper also estimated that mortality due to scabies was zero, which if you think about it, is not entirely true because we know that especially crusted scabies can contribute to super imposed infections that can lead to sepsis that absolutely can be deadly, and things like poststrep glomerial neephritis or rheumatic heart disease can also be a consequence of infections
that are a concepts of scabies. So it's just overall a much bigger deal, and the World Health Organization knows that luckily, and so as of twenty seventeen, scabies are actually considered a neglected tropical disease along with a number of other ectoparasites, and their twenty thirty targets are to
do a few different things to try and really address scabies. First, they're trying to integrate mass drug administration anywhere that prevalence of scabies is higher than ten percent, which sounds, I mean, sounds both low and high. Like imagining ten percent of a population infected with scabies sounds awful, but it also in terms of like mass drug administration campaigns, seems low. But I think part of that is because people can be asymptomatic and treatment can take such a long time
and things like that. So anywhere that which also means that we need better data because we don't necessarily know everywhere where prevalence might be ten percent or greater. And it seems like that is where most of the research on scabies is actually happening, and where the focus really seems to be is on epidemiological level research like where is it, what is the prevalence really and how can we then use public health measures to get control of
this disease? Because we have treatments, we have options, we're just not maybe implementing them in the most effective way currently. So that's where we stand with scabies today.
It's such a huge it's such a huge problem.
It really is. I just I feel like I did not recognize it. I think also, Aaron, you mentioned the stigma that's associated with it. That's a huge, like it is very real, and that is real everywhere across the globe. That's real in developing countries. That is definitely real here in the US. I have seen that firsthand, where if somebody comes into a hospital with scabies, they are treated differently than somebody who doesn't have scabies. And that's a problem.
Mm hmm. There's a lot of I think preconceived notions about scabs that then leads to this sort of treatment that is perpetuates stigma and shame and isolation and all these things.
It's seen as like something that is dirty or something like that. Exactly.
Yeah, it's like literally any person can get scabies.
If you have skin, human skin, you can get scabies. Yeah, yeah, that's that's what it is.
Bottom line.
Well, if you'd like to learn more about scabies, we have a lot of information for you. We do.
I have a handful of papers, but the place where I got most of my information was a great book which I already mentioned, called The Itch Scabies by Eryl Craig, and it's all about scabies. So there's a lot of information there. And then there's again I want to shout out that paper by Cropy from two thousand and six called the Army Itch, a dermatological mystery of the American Civil War.
I have a number of papers, I said already. There was a Lancet article review from two thousand and six just called scabies. It was great, really nice overview. There was one from the Journey All of the American Academy of Dermatology from twenty twenty called Ectoparasites scabies. That was another good one. And honestly, there's a bunch of other papers that are reviews. There's that Global Burden of Disease
study from twenty fifteen. And we'll post the list of sources from this episode and every single one of our episodes on our website, This podcast will Kill You dot Com under the episodes tab.
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And thank you to you listeners. We hope you're not too itchy after listening to this episode.
H and we hope you learned something about scabies.
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