Marek's - I'm so confused

[msyfoopoo]

I am doing a bunch of reading about this because it is possible the bird I sent in for necropsy had the disease (haven't heard back yet, but am a "worst case scenario" planner). So, my question (I have a million, but will limit to just 1 ) is this: can a flock vaccinated for Mareks, so showing all signs of health, be carriers of the disease? For example, a breeder I work with vaccinated all his birds. Is it possible that they can still be carriers and he would never know? (I'm definitely not looking to blame anyone if my bird comes back positive - I know it can be transported on the wind just as easily!)

 

[ronott1]

I am doing a bunch of reading about this because it is possible the bird I sent in for necropsy had the disease (haven't heard back yet, but am a "worst case scenario" planner). So, my question (I have a million, but will limit to just 1 ) is this: can a flock vaccinated for Mareks, so showing all signs of health, be carriers of the disease? For example, a breeder I work with vaccinated all his birds. Is it possible that they can still be carriers and he would never know? (I'm definitely not looking to blame anyone if my bird comes back positive - I know it can be transported on the wind just as easily!)

the vaccine is primarily to stop the cancer that comes with mareks at age 2. They can still get mareks.

I have read that Mareks is environmental and almost all chick are exposed to it by day 3 or so of age. One researcher has found that mixing vaccinated and not vaccinated flock members will develop a strain of mareks that is more lethal for the initial infection. I think we are seeing that with flocks that have a lot of death with the initial infection.

Anecdotally, before the vaccine it was very rare for chickens to die from the initial infection. Now we see it much more often.

 

[msyfoopoo]

A chook CAN be a carrier of the Marek's whether vaccinated on not. The vaccine only helps the bird fight the disease. Read the article by nambrth (sp) on this site to answer your questions. It is long, but the best for we backyard owners. Once a chicken is exposed, they will always be a carrier, vaccinated or not. They might or might not come down with symptoms. Your non-sick birds are fomite, i.e physical carriers of Marek's, as opposed to your sick bird which is an infected carrier.

Blame no one. It can be picked up anywhere. You will never know. There is currently no way to test a live chicken to see if they are a carrier. Observe bio-security so that you don't carry if off your property to someone else's flock.

 

[orrpeople]

Thanks @ronott1 - I've been hearing that California is fairly rampant with it... not sure if that's just hype, but the hypothesis is that dry, warm, windy weather may cause the virus to multiply and spread much quicker. Could also be the lack of a truly accurate vaccination, vaccinations causing mutations, and the list is a mile long...
So, another question I have is that if you are still hatching out chicks,and you have a closed flock, what are you doing with all of them?

 

[orrpeople]

A chook CAN be a carrier of the Marek's whether vaccinated on not. The vaccine only helps the bird fight the disease. Read the article by nambrth (sp) on this site to answer your questions. It is long, but the best for we backyard owners. Once a chicken is exposed, they will always be a carrier, vaccinated or not. They might or might not come down with symptoms. Your non-sick birds are fomite, i.e physical carriers of Marek's, as opposed to your sick bird which is an infected carrier.


Blame no one. It can be picked up anywhere. You will never know. There is currently no way to test a live chicken to see if they are a carrier. Observe bio-security so that you don't carry if off your property to someone else's flock.

Yep - pretty much been reading all yesterday, all night, and all morning (like I said, I'm a worst case scenario girl! I raise Bielefelders just in case we ever need food and eggs in the event of...well, anything!! Lol) I have been super conscientious about my flock, which makes this possibility even more frustrating.
I also need to wait for the report. I'm not good at that either.

 

[msyfoopoo]

BTW - don't focus on age. They can come down with symptoms at any age.

 

[orrpeople]

BTW - don't focus on age. They can come down with symptoms at any age.

Yup. That's what I'm reading. The vet I spoke with at the pathology lab yesterday said 80% diagnosed cases in California are 4-9 months old, 20% are older. Thus, we get the idea that younger birds are more susceptible. Younger birds may be more likely to contract it, but all ages are susceptible.

 

[microchick]

@ronott1 my flock until this summer were 100% not vaccinated, the original flock bought in 2015 bred by a NPIP breeder for resistance. My initial infection with Marek's killed somewhere around 10-15 birds within a very short period of time.....starting somewhere around the first of this year with several deaths prior to that. All with the exception of two birds were all under a year of age so I wouldn't say that the mixing of vaccinated and non vaccinated birds is absolute for the development of a strain of Marek's with a high mortality rate with initial infection.I can only assume that the strain of Mareks that has infected my flock has come in from a wind born vector from an outside flock. Whether or not the strain developed as you suggested is anybody's guess but IMHO, having vaccinated and non vaccinated birds together does not guarantee a more deadly strain of Marek's developing in your flock if they are exposed to the disease. But it does make me wonder how rapidly one of these more deadly forms of Marek's can travel from a flock where maybe this has occured.

Right now I have four standard sized birds with Ocular Marek's Disease but my whole flock is exposed and carriers. Thankfully, I haven't had a recent loss. The last bird that died was a 9 month old bantam cockerel who suffered a suddened death without symptoms of disease.

I did add two female SDW OEGB pullets to the flock in May that were vaccinated. They are at POL and so far doing well. Knock on wood.

My birds seem to decline more during early spring when breeding pressure is on them more than any other time of the year.. Since I can only assume that the initial infection of my flock occured sometime before they were 2 years of age, and I have no idea how infection occured, I'm anxious to see what happens in Feb of 2018 to my flock. That was when the steady losses began this year.

I am planning on bringing in vaccinated and breed resistant Egyptian Fayoumis this spring. They will be brooded away from the coop for 8 weeks and will be used to cross breed with my resistant bantams. Since Fayoumis are genetically resistant to Marek's it's about the only way I can hope to breed resistant birds from my survivors.

 

[ronott1]

@ronott1 my flock until this summer were 100% not vaccinated, the original flock bought in 2015 bred by a NPIP breeder for resistance. My initial infection with Marek's killed somewhere around 10-15 birds within a very short period of time.....starting somewhere around the first of this year with several deaths prior to that. All with the exception of two birds were all under a year of age so I wouldn't say that the mixing of vaccinated and non vaccinated birds is absolute for the development of a strain of Marek's with a high mortality rate with initial infection.I can only assume that the strain of Mareks that has infected my flock has come in from a wind born vector from an outside flock. Whether or not the strain developed as you suggested is anybody's guess but IMHO, having vaccinated and non vaccinated birds together does not guarantee a more deadly strain of Marek's developing in your flock if they are exposed to the disease. But it does make me wonder how rapidly one of these more deadly forms of Marek's can travel from a flock where maybe this has occured.

Right now I have four standard sized birds with Ocular Marek's Disease but my whole flock is exposed and carriers. Thankfully, I haven't had a recent loss. The last bird that died was a 9 month old bantam cockerel who suffered a suddened death without symptoms of disease.

I did add two female SDW OEGB pullets to the flock in May that were vaccinated. They are at POL and so far doing well. Knock on wood.

My birds seem to decline more during early spring when breeding pressure is on them more than any other time of the year.. Since I can only assume that the initial infection of my flock occured sometime before they were 2 years of age, and I have no idea how infection occured, I'm anxious to see what happens in Feb of 2018 to my flock. That was when the steady losses began this year.

I am planning on bringing in vaccinated and breed resistant Egyptian Fayoumis this spring. They will be brooded away from the coop for 8 weeks and will be used to cross breed with my resistant bantams. Since Fayoumis are genetically resistant to Marek's it's about the only way I can hope to breed resistant birds from my survivors.

I may have not articulated well.

The strain has been created and is out there now in the wild. It was not created in your flock but likely came from somewhere. Going to the fair for example or going to visit someone with a flock. Wild birds can move it around too. It is a virus and one that is easily spread.

The point that I did not state clearly is that this new one will kill with the initial infection when they did not before. It is something that the poultry industry made worse because they wanted to lower hens killed by mareks cancer a couple of percentage points.

If I were you, I would vaccinate any chicken that came to my place since the bad strain is there. At my place, I only get mareks cancer and have only seen that one time so I do not vaccinate.

Hopefully a better vaccine will be made available to us too. The one we can get now is not very good

 

[microchick]

Thanks for clarifying that, Ron. I'm in complete agreement with you. I know the bantams that I started using my neighbor's eggs, non vaccinated Amish birds, have seen losses but not nearly as high as with my 'resistant' bred birds.

It makes me wonder if there is a degree of resistance in thise older flocks. They came from a farm within the 5 mile danger zone that you read so much about.

If so it just helps strengthen the idea of breeding for resistance in a Marek's flock.