Lymphoid Leukosis or Marek's - implications for flock?

Discussion in 'Emergencies / Diseases / Injuries and Cures' started by katelk, Dec 1, 2014.

  1. katelk

    katelk Chillin' With My Peeps

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    I am waiting for the final report of a necropsy being done on a 9month old pullet that died. So far all I know is she had a huge tumor on her ovary and tumors on her kidneys and heart.
    They are investigating to see what caused this, but said it may be LL or Marek's.

    My concern is what does this mean for the rest of my flock if she had one of these?
    I breed my own birds and have on occasion sold what I have hatched. I always wait until they are several months old before selling.
    I, of course, am concerned about being able to eat the eggs and meat.
    I have done some research online and am more informed about Marek's.
    I would, however, appreciate it if someone could break it down for me though.

    Will I be able to still breed my birds with either disease?

    Will I need to stop selling birds and close my flock?

    Will LL eggs and meat be ok to eat (I was able to find that it's ok in Marek's)?

    If I can still breed, how often/likely will my chicks have either disease or die from it?

    Thanks for any info or advice!
     
  2. chooks4life

    chooks4life Overrun With Chickens

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    Quote: http://www.merckmanuals.com/vet/poultry/neoplasms/mareks_disease_in_poultry.html

    https://www.backyardchickens.com/a/the-great-big-giant-mareks-disease-faq
    Quote: https://www.backyardchickens.com/t/894589/moving-forward-breeding-for-resistance-to-mareks-disease
    Quote: "Lymphoid leukosis occurs naturally only in chickens. Experimentally, some of the viruses of the leukosis/sarcoma group can infect and produce tumors in other species of birds or even mammals. The infection is known to exist in virtually all chicken flocks except for some SPF flocks from which it has been eradicated. Tumor mortality commonly accounts for ~1%–2% of birds, with occasional losses of ≥20%. Subclinical infection, to which most flocks are subject, decreases several important performance traits, including egg production and quality. The frequency of infection has been reduced substantially in the primary breeding stocks of several commercial poultry breeding companies, particularly egg-type breeders. In recent years this control program has expanded, and infection has become infrequent or absent in certain commercial flocks. The frequency of lymphoid leukosis tumors even in heavily infected flocks is typically low (<4%), and disease is often inapparent. As much as 1.5% excess mortality per wk has been reported in commercial broiler-breeder flocks naturally infected with subgroup J avian leukosis virus."

    Note: humans have tested positive for leukosis and Marek's antibodies too. Theoretically this should not be a concern but if you have immunosuppressed people in your family, or use a lot of artificial antibiotics in yourself or your animals... Or live in a high-radiation area i.e. within the scope of a pylon or transformer... Personally I would not be mixing the two under such circumstances, sometimes viruses do cross species and all of those sorts of conditions make it more likely to happen. Especially also in cases of combined vaccines, overpopulation, etc.

    "Recently, recombinant avian leukosis viruses with the envelope of subgroup B and long terminal repeat of subgroup J have been isolated from field cases of myeloid leukosis in commercial layers. Another recombinant avian leukosis virus with the envelope of subgroup A and long terminal repeat of subgroup E was shown to be a contaminant in commercial Marek's disease vaccines. Thus, recombination between two different subgroups of avian leukosis virus can occur in field conditions and cause economic losses."

    http://www.merckmanuals.com/vet/poultry/neoplasms/lymphoid_leukosis_in_poultry.html

    There's a lot of random chit-chat and back-and-forth in those threads unfortunately but that's par for the course. Hope this helps.

    Best wishes.
     
  3. katelk

    katelk Chillin' With My Peeps

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    So basically if it is LL or Marek's I am screwed and will never be able to breed and sell birds again?

    I do not still have the hens than mothered the group that pullet came from. The rooster has produced a bunch of perfectly fine birds. That was the first bird that was ever symptomatic or anything.

    Where I live everyone around me has chickens. I can even see into one of my neighbor's chicken yard from my own chicken yard.

    Especially something that can be carried on the wind like Marek's seems as if it would be impossible to eliminate, even if I culled my whole flock and started over.
    So what am I to do? It seems as if this means my chicken keeping may as well come to an end unless I am constantly worrying about losing birds and breeding on a harmful disease. Is this correct?
     
  4. chooks4life

    chooks4life Overrun With Chickens

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  5. katelk

    katelk Chillin' With My Peeps

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    Thank you for the follow up. That makes me feel a bit better. I am relatively new to chickens and this one was the first that has ever died. I am a bit emotionally attached to them so having to lose anyone is difficult to imagine. One reason I sell most of what I hatch is so I don't have to trim down my flock that way.

    I feel like if I try to sell to people now, no one will want my birds. I would certainly be wary if someone told me the bird I was buying had a disease.

    The links and everything that I have read I guess made it seem like it was the end of the world lol. I understand what you are saying now about breeding for resistance and getting rid of anyone who breeds weak ones.

    When telling someone you are trying to sell to, what would you even say? Unless they know a lot about it, maybe even if they do, wouldn't they run the other way?
    I'd never secretly sell them, I will just have to eat what I can't sell I guess.
     
  6. chooks4life

    chooks4life Overrun With Chickens

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  7. katelk

    katelk Chillin' With My Peeps

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    @chooks4life -

    I just got the final diagnostic report on the pullet. Apparently they could not tell for certain whether it was LL or Marek's. Here is what it said:

    Diagnosis
    Disseminated lymphosarcoma

    Final Diagnosis Comment
    This bird has disseminated lymphosarcoma or lymphoma. The is the endstage condition of two viruses, Marek's virus and Avian Leukosis virus. In specimens with this degree of decomposition it is extremely difficult to distinguish between the two etiologies. There are histologic lesions and factors suggestive of each condition. The lack of nerve involvement, lack of paralysis, and age of the bird are suggestive of Avian Leukosis virus. The histologic enlargement of the Bursa of Fabricius, perivascular distribution of tumor cells within the liver, and presence of tumors are suggestive of Marek's virus.


    What do you think of this?
    Am I interpreting this correctly in that I still have no idea what caused this?

    Thanks!
     
  8. chooks4life

    chooks4life Overrun With Chickens

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    Very interesting... Was the bird vaccinated against Marek's? If so, she should not have developed tumors, but, it still wouldn't necessarily stop her dying from it.

    I see she wasn't paralyzed... But can you describe her behavior before she died? Any wry-neck type movements, any wasting not related to food intake, was she better and worse cyclically or just steadily worse?

    All of that's not necessarily going to prove anything since both diseases can be atypical or asymptomatic as regards anything but internal examination (which has clearly failed to provide solid results so far anyway). But it can help point to one or the other.

    It does look like yes, you still have no idea what caused this. If you have any other birds looking unwell, or marked for culling, to which you are not particularly attached, culling a fresh one to get tested may give you sure results.

    There are many contaminants in the environment that can cause cancers like this, too, it's possible it's neither disease, but given the prevalence of both diseases and your environment with neighboring flocks I'd probably assume it's one or the other.

    Your chook could also have gotten into some overdose of a carcinogenic chemical at some point or another and this could be the end result, in areas people have inhabited for many decades the ground is often contaminated with long-banned but persistent chemicals which still kill animals, often just managing to strike one out of a number just to make it even more confusing as to what's actually happened, lol...

    Best wishes.
     
  9. katelk

    katelk Chillin' With My Peeps

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    Before she died, her behavior was nearly completely normal. I noticed no more than a week prior that she was just walking slowly and standing around more than normal. She seemed to be more lethargic or depressed. She was still eating, but not much. Although whenever I would bring treats or kitchen scraps she would perk up a little and actually run and grab some with everyone else.

    About a week prior to death, I picked her up and looked her over. Her behavior was different, but so little so that my husband didn't even notice it. She felt fine as far as I could feel and see and I tried to shake it off as me being paranoid.

    After she died just a week later, she was extremely emaciated. She felt to have no meat on her bones at all. I was shocked when I picked her up right before she died. That morning she was acting the same, but a big, young roo tried to mate her and she just collapsed and never recovered.

    So no paralysis, no odd movements (other than just walking slow and seeming depressed), her wasting could have been food related. She went downhill extremely quickly in that one week or so.
     
  10. Eggcessive

    Eggcessive Chicken Obsessed Premium Member

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