Mareks in vaccinated chick?

[tjanssen002]

Sadly we had to cull one of our girls this morning. She was a 10 week Bard Rock bantam and was showing signs of Mareks (paralyzed legs and wings, drooping/weak head/neck). She has been noticeably smaller than the rest of the girls (same age) for the last 3 weeks or so, and especially in the last couple weeks she was struggling to get to the food/water on her own. When we initially noticed her stumbling/paralyzed feet (little over 2 weeks ago), we thought it might be a vitamin deficiency so started giving her extra vitamins (rooster booster, nutridrench) and noticed a little improvement after a couple days. It didn't last so we quaretined her and her condition worsened to the point she was completely unable to move on her own (we even found her upside down a few times) and we made the decision she wasn't going to get better.

From what I've read, this sounds like Mareks. The only problem is the hatchey said that they would all be vaccinated for Mareks. Is it possible for chicks to still succumb to Mareks if they've been vaccinated? Could this have been something else? I'm just worried about the rest of the girls and hope they don't come down with the same thing.

It's our first time raising chickens. We had 5 chicks (we think 2 Bards, 1 brahma, 1 crele old english and a RI red) ordered online, and kept inside in a new brooder (there are chickens next door, though). They've been on super chick feed their whole lives. We haven't noticed any of the same behavior from the other chicks.

 

[Theorrin]

vaccines dont prevent just makes it less likely

 

[U_Stormcrow]

Yes. The Marek's vaccine is generally effective at preventing the worst outcomes of the disease but much less effective in preventing the Marek's infection entirely.

Is it possible the others will succumb? Yes, but unlikely if they are not showing signs at present, and are not subjected to significant stresses in the future.

Have you considered reaching out to your state lab for a necropsy in effort to obtain a confirmed diagnosis?

and out of an abundance of caution, until/unless you get a confirmed diagnosis, you should consider all of your birds to be suspected carriers of the disease, and maintain a closed flock.

 

[MaeM]

Also, I hate to be that person, but how do you know they actually vaccinated all the birds? I ask this because I got two birds with Marek's, they told me they were vaccinated, but the vet said it was unlikely. I don't know what to think, but I guess it's true that some people can lie about it in order to sell the chicks.

 

[U_Stormcrow]

Also, I hate to be that person, but how do you know they actually vaccinated all the birds? I ask this because I got two birds with Marek's, they told me they were vaccinated, but the vet said it was unlikely. I don't know what to think, but I guess it's true that some people can lie about it in order to sell the chicks.

I hate to be that person, but...

One) A lot can go wrong when vaccinating birds, some of it not in the control of those doing the vaccination. Mareks vaccination is particularly prone to this, since it is a tiny dose, only day old birds, and it first has to be diluted to appropriate concentration. Also, the vaccine is apparently rather temperature sensitive. Further, if the birds are then exposed before the vaccine has a chance to trigger a significant immune response (such as by introduction to a marek's positive flock...), all bets are off.

Two) As BYC experiences make clear again and again, a lot of Vets seem to know very little about poultry.

This is a case where its easy to point fingers, but very difficult to point fingers correctly.

 

[Eggcessive]

It would be best if you could contact your state vet lab to find how to send her body to them for a necropsy. Then you could find out if it was really Mareks or something else. It is possible to still get Mareks even when one is vaccinated. But so many other things may look like symptoms of Mareks. If it is too late to get the necropsy on this pullet, then do it if you see another one later with similar symptoms. Here is a list of most state vets, and you should call them if just to find out how to get a necropsy on a backyard chicken:
https://www.metzerfarms.com/poultry-labs.html

 

[tjanssen002]

I appreciate everyone's comments. I can't really know if they were actually vaccinated effectively (especially since they were ordered online and shipped), but figure we bought from a reputable hatchery. I guess that is another thing to keep in mind. We already buried her under a bush (I had some planting to do), so won't be sending her in. Thanks for the list of labs - I was having trouble finding one in AZ. It looks like there is one about 4 hours away, so I will keep that in mind if symptoms pop up in our other girls. It's tough not knowing what you're getting into when starting a new hobby and reality hits you in the face. A community like this helps.

 

[U_Stormcrow]

Happy we were able to provide useful, if not necessarily positive, information.

I raise my own, maintain a closed flock, and am thankfully Marek's negative (and routinely tested for several other things my flocks are negative for, as part of the NPIP program). I still lose freshly hatched birds with some regularity to all kinds of events. Some in my control, most not.

Under a bush is a good place. Sadly, dealing with loss is part and parcel of this hobby. So, at times, is accepting that the reasons for that loss are unknown and sometimes unknowable. Much respect for having the courage to come on here as your first post and ask the question.

@Eggcessive btw is one of BYC's resident experts on poultry illness and injury - what I don't know would fill books, and does! I'm more active on the feed forums.

 

[Eggcessive]

I believe that AZ is one of the more expensive places to get a necropsy. CA, on the other hand is under $30. If you live close enough to take the bird in personally rather than ship, it is less. Most people don’t have necropsies done, unfortunately, but some may if there are future deaths from unknown reasons. I have gotten chicks from a hatchery a couple of times who were vaccinated. No Mareks here, but since have found out the vaccine is not always helpful in preventing it. Mareks virus can mutate, and become more virulent, while the vaccine is “leaky.” Hopefully, no more problems in the future, but you know where to get help if needed. There also is a lab in CA who will send you materials to collect a small blood sample from a trimmed toenail, and you would send in back for a Mareks PCR test. Here is a link for them that you can save:
https://www.vetdna.com/application/forms/aviansubmittalform.pdf