MG Mycoplasma Gallisepticum Need professional opinions (and personal opinions too!)

Discussion in 'Emergencies / Diseases / Injuries and Cures' started by Bazy, Oct 30, 2014.

  1. Bazy

    Bazy Chillin' With My Peeps

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    The possibility of contracting this disease in my flock from a new bird terrifies me. I hatch other people's eggs with my own and keep them quarantined for six weeks. I quarantine any new birds buildings away from my birds with bleached quarantine shoes to change into at the entrance..I put young cockerels in with new quarantined birds to see if they catch a carried disease for four weeks before integrating with my flock.

    I have never had any type of disease in my flock. I vaccinate against mareks, and fowl pox.

    Here is my question:

    Since my flock is totally disease free, could I vaccinate all of them against MG...chicks to adults? My goal is to keep a new carrier bird from slipping by all my safety precautions. The vaccine is over $100, but I don't know if it's reasonable to vaccinate birds that have already been put outside. I don't care about the cost...I just don't want to have to start over if there is an outbreak because I sell and trade birds and hatching eggs.

    Is the vaccine effective in older, healthy birds?
     
  2. Amina

    Amina Chillin' With My Peeps

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    Hi! I totally understand your concern. I'm thinking about this for my own flock too, because I intend to hatch other peoples' eggs in the spring.

    You can reduce the transmission of MG through hatching eggs by heat treating the hatching eggs first, before normal incubation. It reduces viability of the eggs a little bit (~10%), but I think it is definitely something to consider.
    http://www.jstor.org/discover/10.23...2&uid=70&uid=4&uid=3739256&sid=21104442077451

    Keep in mind that for many diseases, available vaccines do NOT prevent your birds from becoming infected and becoming carriers. They just prevent symptoms. This is true in the case of Mareks - birds exposed to Mareks will still become carriers, but they will not develop tumors from Mareks.

    The MG vaccines out there are actually weakened live MG strains. Vaccinated birds remain carriers of the weakened strain for life. One of the available vaccine MG strains is still fully pathogenic to turkeys. There are two others that are not so pathogenic to other poultry species though. So if you do choose to vaccinate for MG, I would go with the kind that is not pathogenic to other species. Even if you don't have turkeys, your customers might. I think the kind that's less risky for other species is also a bit less effective as a chicken vaccine though, unfortunately. I can't remember right now where I read that, but I can look it up later if you're interested.
    http://www.merckmanuals.com/vet/pou...lasma_gallisepticum_infection_in_poultry.html

    I am unclear on whether birds vaccinated with these strains can become asymptomatic carriers of pathogenic MG strains. Maybe somebody else here knows??
     
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  3. Amina

    Amina Chillin' With My Peeps

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    You might want to read this as well: http://www.oie.int/fileadmin/Home/eng/Health_standards/tahm/2.03.05_ AVIAN_MYCO.pdf

    What I gather from this is that there are 3 available weakened live vaccines: F-strain MG, strain 6/85, and ts-11. The idea is that you're infecting your flock with a non-pathogenic strain of MG, so that if they are later exposed to pathogenic MG, they won't be able to catch it since they are already infected with the non-pathogenic kind.

    F-strain provides the best protection for chickens, but it's possible for other birds to catch this strain. If a chicken catches it, no big deal - it won't make them sick. But it would make turkeys sick.

    Strains 6/85 and ts-11 are safer for other poultry than the F-strain. These two strains are very hard for other birds to catch, and they're not pathogenic to other species.

    There's also a live vaccine for MS that works about the same as the ts-11 vaccine for MG, in case you decide you're interested in that one too.

    Vaccination on commercial poultry farms is done around 12-16 weeks of age, but it can be done in older or younger birds. The birds do need to be at least 2-4 weeks old for the vaccination to be successful, and of course vaccination must be done before they might be exposed to pathogenic MG.

    There are different preferred ways of administering these live vaccines:
    F-strain - intranasal or eyedrop
    ts-11 - eyedrop
    6/85 - aerosol spray


    There are also inactivated vaccines, which I didn't know about previously. These are basically whole MG cells that are killed and mixed with oil. These are called MG bacterins. These inactivated vaccines are administered by injection. Birds can't be vaccinated before 1-2 weeks of age, or they may not be protected against MG. The downside of using this vaccine is that, although your birds won't have symptoms of MG, they will still be infected by MG if they are exposed to it. They would be asymptomatic carriers.
     
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  4. Bazy

    Bazy Chillin' With My Peeps

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    So the end result is the vaccine most effective for chickens could make carriers of the disease that could infect other birds, or the vaccine could mask (minimize) the symptoms of an infected, vaccinated bird and render them a carrier of the actual disease communicable to other unvaccinated chickens or other fowl.

    In short, vaccinating them would only mask the disease should they ever contract it and quite possibly, unknowingly send carrier birds to other flocks?

    Maybe it's better to know you have the disease and depopulate than to create bigger problems by vaccination that could result in sending carrier birds into the population...Carrier birds that would be asymptomatic under stress. I am relying now on the stress factor to cause the symptoms to manifest while in quarantine.

    (Thank you so much for helping me work this out and think it over)
     
  5. Amina

    Amina Chillin' With My Peeps

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    Personally, I kindof like the idea of vaccinating with ts-11 or 6/85. Those live strains do help prevent infection by pathogenic strains, and those particular vaccine strains are difficult to spread from bird to bird even in the cramped conditions of a factory farm. I'm not sure if we as backyard chicken keepers have access to those vaccines, though. When I searched for mycoplasma vaccines available, the only one I found was the inactivated kind. Personally I wouldn't want to use that unless I knew I had an infected flock that I intended to keep closed. I think there is just too much risk otherwise of unknowingly having carrier birds, since the inactivated vaccine will prevent symptoms but not infection.
     
  6. Amina

    Amina Chillin' With My Peeps

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    I'm glad I could help you think this through!
     

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