Eupedia Forums
Site NavigationEupedia Top > Eupedia Forum & Japan Forum
Results 1 to 8 of 8

Thread: Did the steppe people bring leprosy as well as the plague?

  1. #1
    Advisor Achievements:
    VeteranThree Friends50000 Experience PointsRecommendation Second Class
    Awards:
    Posting Award
    Angela's Avatar
    Join Date
    02-01-11
    Posts
    15,307
    Points
    279,553
    Level
    100
    Points: 279,553, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 99.6%


    Ethnic group
    Italian
    Country: USA - New York



    1 out of 1 members found this post helpful.

    Did the steppe people bring leprosy as well as the plague?

    So asks Iain Mathiesen.

    See: Ben Kraus-Kyora
    "Ancient DNA study reveals HLA susceptibility locus for leprosy in medieval Europeans"


    https://www.nature.com/articles/s41467-018-03857-x

    I thought it was a hot weather disease, no?

    "Leprosy, a chronic infectious disease caused by Mycobacterium leprae (M. leprae), was very common in Europe till the 16th century. Here, we perform an ancient DNA study on medieval skeletons from Denmark that show lesions specific for lepromatous leprosy (LL). First, we test the remains for M. leprae DNA to confirm the infection status of the individuals and to assess the bacterial diversity. We assemble 10 complete M. lepraegenomes that all differ from each other. Second, we evaluate whether the human leukocyte antigen allele DRB1*15:01, a strong LL susceptibility factor in modern populations, also predisposed medieval Europeans to the disease. The comparison of genotype data from 69 M. leprae DNA-positive LL cases with those from contemporary and medieval controls reveals a statistically significant association in both instances. In addition, we observe that DRB1*15:01 co-occurs with DQB1*06:02 on a haplotype that is a strong risk factor for inflammatory diseases today."

    "
    A recent ancient DNA (aDNA) analysis has revealed a high level of M. leprae genome conservation over the past 1000 years, indicating that the leprosy epidemic during the European Middle Ages was unlikely to be due to particularly virulent strains2. Instead, other factors such as malnutrition, co-infections, and host genetics may have increased disease susceptibility in the medieval period. At present, leprosy is virtually absent in Europe, but still remains a big health problem in South-East Asia (e.g., India), North and Central Africa (Central African Republic, Democratic Republic of the Congo), Oceania (Indonesia, Papua New Guinea) and the Americas (Brazil, Mexico)3. All 10 modern human M. leprae genomes sequenced up to now fall in five distinct phylogenetic branches that show a specific geographic distribution pattern2."

    "
    Leprosy was endemic during the Middle Ages in Europe, where it reached its greatest prevalence between AD 1200 and 14001. "

    "
    Among the St. Jørgen samples, branch 3-strains were most abundant (n = 9) and very similar to extant strains recently identified in European red squirrels21 (Fig. 3). Interestingly, modern branch 3-bacteria have the ability to infect at least three different hosts including humans and squirrels21"

    It's the damn rodents again.

    "
    The comparison of the rs3135388-T frequencies from the 69 LL cases with the DRB1*15:01 data from modern controls revealed a statistically significant association. To strengthen this finding, we further analyzed whether the allele frequency in the cases was different from that of medieval controls. The controls (i) were selected from sites that were geographically close and dated earlier or contemporaneous to St. Jørgen, (ii) showed no osteological evidence of the severe LL form of the disease and (iii) were M. leprae DNA-negativ."

    "Notably, the medieval control frequency was slightly but significantly higher than today (p = 0.024, OR = 1.41, Table 1), possibly indicating weak selection against this allele during or since medieval times. This observation raises the question of how leprosy might have led to reduced reproductive fitness given that affected people, at least in modern populations, rarely die from the disease. "
    Mathiesen's question is based on this:
    "
    Note that the rs3135388 T allele was introduced to Europe by Bronze Age Steppe migrations.

    [IMG][/IMG]

    I don't know what to think about this. Did steppe samples from the Bronze Age show signs of leprosy? Was there no sign of it in Europe before the Middle Ages.

    If it's true it must have been like the Apocalypse and the four horsemen:Pestilence, War, Famine, and Death.





    Non si fa il proprio dovere perchè qualcuno ci dica grazie, lo si fa per principio, per se stessi, per la propria dignità. Oriana Fallaci

  2. #2
    Regular Member Achievements:
    1 year registered1000 Experience Points

    Join Date
    18-03-17
    Posts
    271
    Points
    1,811
    Level
    11
    Points: 1,811, Level: 11
    Level completed: 87%, Points required for next Level: 39
    Overall activity: 9.0%


    Ethnic group
    swiss,italian
    Country: Germany



    i'll probably have to read it a bit more carefully but from my understanding the steppe had a higher frequency of an allele that is weaker against leprosy. so if we take in consideration that the allele was later negatively selected due to leprosy we could assume that they did not have leprosy or not more than HGs and farmers.

  3. #3
    Regular Member Achievements:
    1000 Experience Points1 year registered

    Join Date
    05-01-18
    Posts
    238
    Points
    2,205
    Level
    13
    Points: 2,205, Level: 13
    Level completed: 19%, Points required for next Level: 245
    Overall activity: 6.0%


    Ethnic group
    Irish/British
    Country: United States



    1 out of 1 members found this post helpful.
    Can't blame everything on the Indo-Europeans:

    The DNA comparison showed that one type of leprosy found in Europe 1,000 years ago is the same as one present in the Middle East now.
    This strengthened the view that the disease spread during the Crusades, said Johannes Krause, from the University of Tübingen, Germany, one of the authors of the work. This was a period when Christian armies fought for control of what they called the Holy Land.
    It remains unclear which direction the disease spread, but "lines of evidence suggest an Asian origin of the disease", as the earliest evidence of leprosy comes from a 4,000-year old skeleton found in India.
    "It's clear that leprosy has created a strong selective pressure on the immune system. The European Caucasian populations have acquired resistance to leprosy, they have certain characteristic mutations in genes that make them less susceptible," Prof Cole told BBC News.
    Google "Medieval skeletons give clues to leprosy origins" (still can't link)

  4. #4
    Advisor Achievements:
    VeteranThree Friends50000 Experience PointsRecommendation Second Class
    Awards:
    Posting Award
    Angela's Avatar
    Join Date
    02-01-11
    Posts
    15,307
    Points
    279,553
    Level
    100
    Points: 279,553, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 99.6%


    Ethnic group
    Italian
    Country: USA - New York



    Quote Originally Posted by CrazyDonkey View Post
    Can't blame everything on the Indo-Europeans:





    Google "Medieval skeletons give clues to leprosy origins" (still can't link)
    I agree with that, which is why I said I wasn't sure what to make of this. However, once again, it isn't "native" to Europe, and may have come by way of the steppe.

    Also, the other diseases to which it makes people more susceptible have a higher incidence in northern Europe, where there is more steppe ancestry.

    Anyway, they need to do a lot more research. What we can be grateful for is that we know have medication to treat it, as it's a horror of a disease. I can't think of one worse except possibly plague, although imo that's probably better: at least you die quickly.

  5. #5
    Moderator Achievements:
    1 year registeredTagger Second ClassThree Friends25000 Experience Points
    Awards:
    Most Popular

    Join Date
    21-10-16
    Posts
    1,725
    Points
    26,601
    Level
    50
    Points: 26,601, Level: 50
    Level completed: 6%, Points required for next Level: 949
    Overall activity: 5.0%


    Ethnic group
    Multiracial Brazilian
    Country: Brazil



    0 out of 1 members found this post helpful.
    Wow what did those steppes have that so many diseases sprung up from there? I mean, usually I had read that the appearance of awful diseases was most often related to close contacts of humans with many animal domesticates in overcrowded and insanitary conditions, especially in pre-modern fortified cities and villages, where people most often lived packed onto each other, often with animals within their homes. Was the mobile living of steppe peoples in huge, open grasslands, without big crowded settlements, with a lot of available land, and practicing a very extensive kind of pastoralism, conducive to make their homeland become such a pool of diseases? Or was it just bad luck from living somewhere full of disease-prone rodents?

  6. #6
    Moderator Achievements:
    1 year registeredTagger Second ClassThree Friends25000 Experience Points
    Awards:
    Most Popular

    Join Date
    21-10-16
    Posts
    1,725
    Points
    26,601
    Level
    50
    Points: 26,601, Level: 50
    Level completed: 6%, Points required for next Level: 949
    Overall activity: 5.0%


    Ethnic group
    Multiracial Brazilian
    Country: Brazil



    Quote Originally Posted by Ailchu View Post
    i'll probably have to read it a bit more carefully but from my understanding the steppe had a higher frequency of an allele that is weaker against leprosy. so if we take in consideration that the allele was later negatively selected due to leprosy we could assume that they did not have leprosy or not more than HGs and farmers.
    Exactly, I was also not sure how to interpret their conclusions. If steppe populations had higher level of genetic susceptibility to leprosy, I'd assume that, just like Native Americans weren't genetically adapted to resist Old World diseases, that would more easily correlate with leprosy not being particularly common in the steppe, otherwise they would've been subjected to negative selection for a long time before their arrival in Central Europe. We expect people where a certain disease has existed for centuries or milennia to have lower levels of a gene mutation that makes one weaker to it. I honestly didn't understand their point...

  7. #7
    Advisor Achievements:
    VeteranThree Friends50000 Experience PointsRecommendation Second Class
    Awards:
    Posting Award
    Angela's Avatar
    Join Date
    02-01-11
    Posts
    15,307
    Points
    279,553
    Level
    100
    Points: 279,553, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 99.6%


    Ethnic group
    Italian
    Country: USA - New York



    Quote Originally Posted by Ygorcs View Post
    Wow what did those steppes have that so many diseases sprung up from there? I mean, usually I had read that the appearance of awful diseases was most often related to close contacts of humans with many animal domesticates in overcrowded and insanitary conditions, especially in pre-modern fortified cities and villages, where people most often lived packed onto each other, often with animals within their homes. Was the mobile living of steppe peoples in huge, open grasslands, without big crowded settlements, with a lot of available land, and practicing a very extensive kind of pastoralism, conducive to make their homeland become such a pool of diseases? Or was it just bad luck from living somewhere full of disease-prone rodents?
    I think rodents are a big, big, part of it.

    This is from the CDC. I've hiked out west, and read all the advisories. Not a good idea to hike in shorts and camisoles. I always wore jeans, socks, boots and a loose, long sleeved cotton top. It's also important to check yourself for flea bites, and don't feed the cute animals. Despite the fact that I love rabbit, I also don't eat the wild ones out there.

    "The bacteria that cause plague, Yersinia pestis, maintain their existence in a cycle involving rodents and their fleas. In urban areas or places with dense rat infestations, the plague bacteria can cycle between rats and their fleas. The last urban outbreak of rat-associated plague in the United States occurred in Los Angeles in 1924-1925.Since that time, plague has occurred in rural and semi-rural areas of the western United States, primarily in semi-arid upland forests and grasslands where many types of rodent species can be involved. Many types of animals, such as rock squirrels, wood rats, ground squirrels, prairie dogs, chipmunks, mice, voles, and rabbits can be affected by plague. Wild carnivores can become infected by eating other infected animals.
    Scientists think that plague bacteria circulate at low rates within populations of certain rodents without causing excessive rodent die-off. These infected animals and their fleas serve as long-term reservoirs for the bacteria. This is called the enzootic cycle.
    Occasionally, other species become infected, causing an outbreak among animals, called an epizootic. Humans are usually more at risk during, or shortly after, a plague epizootic. Scientific studies have suggested that epizootics in the southwestern United States are more likely during cooler summers that follow wet winters. Epizootics are most likely in areas with multiple types of rodents living in high densities and in diverse habitats."
    https://www.cdc.gov/plague/transmission/index.html

    I used to think that since rats thrived in urban areas, that would be the areas where it might develop, but apparently they think that it's epizootics which are the big problem and for that you need as they say, " multiple types of rodents living in high densities and in diverse habitats."

    Arid grasslands are the perfect environment, apparently.

    I do think farming was wonderful for the spread of disease too, especially enteric diarrhea, which I'm sure played havoc with infants, and particularly as they didn't boil the milk that came from their animals. Probably turning it into cheese would be ok, but drinking it for an infant spreads TB among other things. I think TB in general is connected to domestic animals, isn't it? That was still a scourge in the last century, and resistant strains keep popping up.

    As to this comment:
    "Exactly, I was also not sure how to interpret their conclusions. If steppe populations had higher level of genetic susceptibility to leprosy, I'd assume that, just like Native Americans weren't genetically adapted to resist Old World diseases, that would more easily correlate with leprosy not being particularly common in the steppe, otherwise they would've been subjected to negative selection for a long time before their arrival in Central Europe. We expect people where a certain disease has existed for centuries or milennia to have lower levels of a gene mutation that makes one weaker to it. I honestly didn't understand their point..."

    I'm not sure I'm getting it right but they seemed to be saying that the selection against it is quite weak, so, I don't know how that factors in. It seems to me that if people were exposed to it, they'd probably get it again. What may have happened is that the isolation, while cruel, was effective, and it just wasn't around as much to infect people. Certainly, the other diseases tied to the locus are still pretty prevalent. The other thing is that you can live with leprosy for decades, even though you might wish you were dead. It's not like plague where you could be dead for twenty-four hours.

    I think they need to find the first leprosy samples, or at least early ones, in the steppe during the Bronze Age, but not in Europe, in order to come to conclusions like that.

    Oh, it just occurred to me, influenza also comes from the east, but in that case from poultry in heavily farming China.

    I don't know about small pox, or the much milder chicken pox.

  8. #8
    Regular Member Achievements:
    1000 Experience Points1 year registered

    Join Date
    05-01-18
    Posts
    238
    Points
    2,205
    Level
    13
    Points: 2,205, Level: 13
    Level completed: 19%, Points required for next Level: 245
    Overall activity: 6.0%


    Ethnic group
    Irish/British
    Country: United States



    Quote Originally Posted by Ygorcs View Post
    If steppe populations had higher level of genetic susceptibility to leprosy...
    From the quote I provided (my brackets):

    The European Caucasian populations [R1b?] have acquired resistance to leprosy, they have certain characteristic mutations in genes that make them less susceptible," Prof Cole told BBC News.
    It is pretty clear from the article I quoted that leprosy in Europe in the Middle Ages was brought back by the Crusaders. If the Indo-Europeans brought anything it was "mutations in genes that make them less susceptible".

    Now where and when such mutations were selected for is an open question: "the earliest evidence of leprosy comes from a 4,000-year old skeleton found in India."

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •