Mareks Vaccine


Squeaky Wheel
11 Years
Feb 11, 2008
Waterloo, Nebraska
There has been discussion on another board regarding Mareks. I think there is a lot of misinfortion out there. I know people on this board have discussed it also. Yesterday, I e-mailed Dr. Fulton at MSU. He specializes in poultry. He was very helpful when we were hit with Mareks last year. This is
what I asked him:

Last year I had a bird with Mareks. You
very kindly advised me about her health issues via
e-mail. I thank you very much for that. I would like
to ask you about vaccinations. I hatched 23 chicks
this year in an incubator and vaccinated all for
Mareks. I have poultry acquaintances that are sure
that having these chicks vaccinated will infect any
bird they ever come in contact with for the rest of
their lives. I believe it is so predoninate in the
environment that I would be crazy not to vaccinate.
As an expert, would you please tell me if these
vaccinated chicks will turn out to be "Typhoid
Mary's." Would you please tell me what the risks of
vaccination are and if vaccinated birds are a real
threat to others?
Thank You For Your Time

He very kindly sent me a prompt response. This is what he said:

Dear Jody:

I understand your and your poultry pal's concerns but you are right in your thinking about Marek's disease. Marek's disease virus is everywhere. In fact, the vaccination of poultry for Marek's disease is a race to see which virus is going to win in the bird.....the vaccine virus or the disease causing virus. While it is true that Marek's disease vaccinated birds are infected with the vaccine virus for life,
I am not aware of them shedding the vaccine virus. The good news is that the vaccine viruses do not cause disease so your chickens are safe and not "Typhoid Marys." The other vaccines used in poultry do not cause
"Typhoid Marys" except for almost all vaccines used to protect against Infectious Laryngotracheitis. Chickens vaccinated with those vaccines can shed the vaccine virus and the vaccine virus will make non-vaccinated chickens sick.

As for vaccinating your chickens for other diseases, I only recommend vaccinating chickens against diseases you have had or that are in your area. In most cases, that only includes fowl pox. Please note that chicken pox is a human disease and not a chicken disease. The virus that causes chicken pox in humans does not cause disease in chickens
nor do humans get it from chickens.

Hope this helps,

R. M. Fulton, D.V.M., Ph.D.

There is a lot of misinformation out there on the web regarding vaccinations and Mareks. People get the effects of one vaccine confused with another, etc. If birds vaccinated for Mareks are so contagious, why are they allowed in the shows? The virus in the Mareks vaccine is not the same one that causes the disease. It is just similar enough to create immunity. We all should check our sources regarding such things before passing on misinformation. Last year when my flock had an issue with Mareks, I contacted local vets and vets at poultry departments of universities with ag departments.
They all told me the same thing. And all of the university people told me that Dr Fulton was the foremost authority on it. I think I can trust my sources.

I hope that Dr. Fultons response can help people on this board as well as the other forum I posted it on.
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12 Years
Jan 22, 2008
Thank you for that post. I was starting to worry because the chicks I have coming will be vax for Mareks and I was starting to worry after reading that they shed the virus for life. That puts me at ease.


Premium Feather Member
13 Years
Jan 11, 2007
British Columbia, Canada
Thanks for posting that. I know the confusion comes from the chicks that get sick with Mareks after being vacinated. He put that very well, it's a race with the 2 viruses to see which will get the chicken. If the vacine virus wins then the chickens will not shed, and will not be sick. If the disease wins the race the chick MAY get sick, and will be a carrier which sheds the disease to others. If the chick is not vacinated it will get exposed as the disease is everywhere, and it will probably get some symptoms depending on age, and will be a carrier which spread the disease.

Great set of choices..... Anyway best bet is to vacinate rigth at hatch time, and keep chicks strictly isolated from all chickens for a week at least, 2 is better.


Squeaky Wheel
11 Years
Feb 11, 2008
Waterloo, Nebraska
Some people give boosters to adult birds if they were vaccinated as chicks. I have no idea of the dosage or if it is necessary or effective. If your chickens were not vaccinated as chicks, it will not do them any good to be vaccinated as adults. They would have already been exposed in the environment. Mareks disease is caused by a herpes virus that is prevailent in the environment. It often stays latent in the chicken and rears it's ugly head in times of stress. The virus will not manifest itself in all chickens, however, it has a high mortality rate in the birds it does.


In the Brooder
11 Years
May 3, 2008
I've been all over here this morning! These symtoms resemble what we've seen in the disable auracana. She has poor balance, left side issues. Left wing droops most of the time and her legs seem weak She seems happy, but just might fall over. She is separate and has been for about 3 weeks now. She has good appetite.

She has her own pen with a house, good water and feed. DH made sure she didn't HAVE to hop up onto the pallet her little house sets on or even hop into the house. He has quite a step arrangement.

Edited: A couple questions for the experienced:

1. How do you handle the recovered chickens being around other chickens. Is this so prevalent that the fact that they are always 'carriers' makes little difference to the others?

2. Do the recovered chickens have future episodes and seizures?

2nd edit: I just saw that picture of a chicken's foot with Marek's. That isn't our foot! Her feet are fine, she just folds up and almost falls over.
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Flock Mistress
12 Years
Jan 1, 2008
Yes and a good one to sticky too!

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