Marek Vaccine

[Stephine]

I'm trying to understand that. Natural immunity comes from exposure. But if isolated and do not get exposed, they do not come into contact with the virus to develop the antibodies.

What am I missing here?

Maybe a more mature immune system can fight the virus off more easily? There are many diseases in humans for example that are a big problem for an infant, but not so much for an older child or adult… I am not claiming to be an expert.

 

[Stephine]

Maybe a more mature immune system can fight the virus off more easily? There are many diseases in humans for example that are a big problem for an infant, but not so much for an older child or adult… I am not claiming to be an expert.

should add: the immune system doesn’t have to get trained on the virus itself, it can get trained on similar enough viruses that are less harmful. The vaccine itself (at least one of them) is based on a Turkey virus similar to Marek‘s but not (as?) harmful to chickens.

 

[Wyorp Rock]

Ah, okay! I have seen it in different places for avian medicine online, but here it is in Gail Damerow‘s „Chicken Health Handbook“.

Yes, I've seen her have the same type of wording on blogs for hatcheries, but in her own blog, she doesn't mention chicks being isolated for 5 months gaining "immunity". She advocates vaccination but readily admits that it's not perfect either, birds can still show infection from the virus.
https://gaildamerow.com/why-do-some-chickens-resist-mareks-disease/

And let's be absolutely practical here. Could you raise and protect chicks for 5 months and ensure that they are NOT exposed to Marek's whatsoever during that time?
They would have to be in a building with ventilation pulling air out, you'd have to suit up each time they were tended to and they certainly couldn't be outside getting fresh air/sunshine since "Marek's is everywhere". They'd have to be raised in a bubble, then what do you do when you do put them outside and they are exposed to every other pathogen, parasite, bacteria that they were sheltered from for 5 months.

The above is probably a bit overboard, but where does common sense come into play...

None of its perfect, so I would recommend everyone to research heavily, read the published studies on the vaccine and make a decision from there. Also read posts from others who have Marek's + flocks, what they do/don't. It may surprise you that some still will not vaccinate, while others only will.
And, some have had great success introducing breeds/strains of birds that are touted to already be genetically "resistant" to the Virus while others have lost them and findings show they succumbed to the disease. So..."immunity" imho, is not a term I'd use. "Resistant" is "better".

 

[JacinLarkwell]

I will say, while it could easily be a multitude of other things, none of my birds that were over a year old when I got my infected chicks show any signs at all of Mareks. I have to assume they are infected because they're in the same pens as the birds that brought it, but the only ones I've lost to it that i know of are ones under a year

 

[BonnieBlue]

should add: the immune system doesn’t have to get trained on the virus itself, it can get trained on similar enough viruses that are less harmful. The vaccine itself (at least one of them) is based on a Turkey virus similar to Marek‘s but not (as?) harmful to chickens.

That makes more sense. A more developed immune system having more resistance.

Seeing the word "immunity", makes me think exposure and developed antibodies.

 

[BonnieBlue]

I will say, while it could easily be a multitude of other things, none of my birds that were over a year old when I got my infected chicks show any signs at all of Mareks. I have to assume they are infected because they're in the same pens as the birds that brought it, but the only ones I've lost to it that i know of are ones under a year

My girls are just over six months. If I can get them to spring without marek's, they should be much more resistant. If (big if) I can get in a position to move, I am shooting for next summer, and that is when I would get a few more chicks. The five I have now would be a year old then. It would make sense to get vaccinated for any additional, and hope the older ones had developed a resistance.

 

[Stephine]

Yes, I've seen her have the same type of wording on blogs for hatcheries, but in her own blog, she doesn't mention chicks being isolated for 5 months gaining "immunity". She advocates vaccination but readily admits that it's not perfect either, birds can still show infection from the virus.
https://gaildamerow.com/why-do-some-chickens-resist-mareks-disease/

And let's be absolutely practical here. Could you raise and protect chicks for 5 months and ensure that they are NOT exposed to Marek's whatsoever during that time?
They would have to be in a building with ventilation pulling air out, you'd have to suit up each time they were tended to and they certainly couldn't be outside getting fresh air/sunshine since "Marek's is everywhere". They'd have to be raised in a bubble, then what do you do when you do put them outside and they are exposed to every other pathogen, parasite, bacteria that they were sheltered from for 5 months.

The above is probably a bit overboard, but where does common sense come into play...

None of its perfect, so I would recommend everyone to research heavily, read the published studies on the vaccine and make a decision from there. Also read posts from others who have Marek's + flocks, what they do/don't. It may surprise you that some still will not vaccinate, while others only will.
And, some have had great success introducing breeds/strains of birds that are touted to already be genetically "resistant" to the Virus while others have lost them and findings show they succumbed to the disease. So..."immunity" imho, is not a term I'd use. "Resistant" is "better".

Not arguing with any of this. I am certain Damerow has good sources to base her statements on. The fact she doesn’t mention it in her blog doesn’t mean much if she writes about it in her book. Wouldn’t quibble too much about the term immunity - there are grades of immunity, doesn’t all have to be absolute. Our people vaccines don’t all guarantee absolute immunity either. Immunity similar to the Marek‘s vaccine in this case might be the benchmark.
And I agree, as a strategy it would be difficult to do, though I am pretty sure there are Marek‘s free flocks out there and while success of course isn’t guaranteed, there are definitely ways you can improve your chances of keeping young chickens Marek‘s free for a few months.
I can’t swing it - I have chickens for fun and superior egg quality, and we have a rental cottage on our farm, and the renter is living a normal life with frequent visitors who all walk by the chicken area. I do what’s most practical for me and that’s buying vaccinated chicks…
The reason I talked about the Marek‘s 5 months thing at all was to reassure the OP that her older chickens would be safe if they have been Marek‘s free so far…

 

[Stephine]

Yes, I've seen her have the same type of wording on blogs for hatcheries, but in her own blog, she doesn't mention chicks being isolated for 5 months gaining "immunity". She advocates vaccination but readily admits that it's not perfect either, birds can still show infection from the virus.
https://gaildamerow.com/why-do-some-chickens-resist-mareks-disease/

And let's be absolutely practical here. Could you raise and protect chicks for 5 months and ensure that they are NOT exposed to Marek's whatsoever during that time?
They would have to be in a building with ventilation pulling air out, you'd have to suit up each time they were tended to and they certainly couldn't be outside getting fresh air/sunshine since "Marek's is everywhere". They'd have to be raised in a bubble, then what do you do when you do put them outside and they are exposed to every other pathogen, parasite, bacteria that they were sheltered from for 5 months.

The above is probably a bit overboard, but where does common sense come into play...

None of its perfect, so I would recommend everyone to research heavily, read the published studies on the vaccine and make a decision from there. Also read posts from others who have Marek's + flocks, what they do/don't. It may surprise you that some still will not vaccinate, while others only will.
And, some have had great success introducing breeds/strains of birds that are touted to already be genetically "resistant" to the Virus while others have lost them and findings show they succumbed to the disease. So..."immunity" imho, is not a term I'd use. "Resistant" is "better".

Just came across this article https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2643530/ Thought you might be interested. As an aside, here, too, scientists talk about varying levels of immunity, not one absolute. But you are right, in laymen’s terms it is probably better to say resistance, because the term immunity might be more linked to the legal meaning in many people’s minds.

 

[Amelise]

@Wyorp Rock @Stephine @BonnieBlue

I have this book and the quote shown by Stephine makes more sense with the full paragraph. In this paragraph from “The Marek’s Virus” section Damerow says:

“The virus is not transmitted by means of hatching eggs. In fact, a newly hatched chick is briefly protected if the mother hen transmits a high antibody level through her eggs. Chicks should be brooded away from mature birds, however, since the first few weeks of life are the most critical time for infection. Chicks that are isolated until the age of 5 months develop a natural immunity that helps them overcome the Marek’s virus as adults.” (Pg 261-262).

I thinks Damerow meant to isolate the chicks from adults birds, not the Marek’s disease, but I’m not completely sure.
How would the birds gain immunity to a virus they’ve never been in contact with? The author insinuated near the beginning of the book that exposing very young and growing chicks to soil will help them build immunity, so I doubt she meant isolating them from the virus itself.

 

[Stephine]

@Wyorp Rock @Stephine @BonnieBlue

I have this book and the quote shown by Stephine makes more sense with the full paragraph. In this paragraph from “The Marek’s Virus” section Damerow says:

“The virus is not transmitted by means of hatching eggs. In fact, a newly hatched chick is briefly protected if the mother hen transmits a high antibody level through her eggs. Chicks should be brooded away from mature birds, however, since the first few weeks of life are the most critical time for infection. Chicks that are isolated until the age of 5 months develop a natural immunity that helps them overcome the Marek’s virus as adults.” (Pg 261-262).

I thinks Damerow meant to isolate the chicks from adults birds, not the Marek’s disease, but I’m not completely sure.
How would the birds gain immunity to a virus they’ve never been in contact with? The author insinuated near the beginning of the book that exposing very young and growing chicks to soil will help them build immunity, so I doubt she meant isolating them from the virus itself.

No, the birds do need to be protected from the Marek‘s virus. The immunity does happen, but not from direct exposure to the virus. I don’t know if they actually know how it happens or if it has just been an observation. Maybe there are enough viruses in the environment that are similar enough to Marek‘s to cause a good immune response, but different enough not to make them sick. This is known for the turkey virus - maybe there are others? Maybe the immune system in general works better after that time?
But exposure to the Marek‘s virus directly is a bad idea.
She does talk about how it is possible for chicks to build resistance with exposure in their first two weeks of life, while they still have protection from their mother’s antibodies. She also says it might not work. New exposure after the first two weeks it’s definitely a bad idea.