Mareks diagnosed in “vaccinated” pullets

ChocolateMouse

Free Ranging
7 Years
Jul 29, 2013
5,603
17,960
707
Cleveland OH
https://www.backyardchickens.com/articles/the-great-big-giant-mareks-disease-faq.66077/

The short short version is;
  • Depending on what test was done during the necropsy a vaccinated chicken may come up as having died from Mareks because of the reaction of the vaccine. If it was diagnosed through tumors it's probably accurate, but bloodwork may not be.
  • Chickens require a certain number of months in a mareks-free environment to build up their antibodies, so exposing them to mareks early can cause the disease to manifest later despite the vaccine.
  • The vaccine, depending on which one it is and which strain you have, may be very ineffective even when administered effectively.
  • The vaccine does never prevents the infection from taking place, it prevents the symptoms from developing.
  • Vaccinated birds still "catch" mareks when exposed. Your "healthy" vaccinated birds are carriers for life too and can spread it to and kill unvaccinated birds.
 

nobrainslesscash

Chirping
Jun 7, 2011
4
6
62
https://www.backyardchickens.com/articles/the-great-big-giant-mareks-disease-faq.66077/

The short short version is;
  • Depending on what test was done during the necropsy a vaccinated chicken may come up as having died from Mareks because of the reaction of the vaccine. If it was diagnosed through tumors it's probably accurate, but bloodwork may not be.
  • Chickens require a certain number of months in a mareks-free environment to build up their antibodies, so exposing them to mareks early can cause the disease to manifest later despite the vaccine.
  • The vaccine, depending on which one it is and which strain you have, may be very ineffective even when administered effectively.
  • The vaccine does never prevents the infection from taking place, it prevents the symptoms from developing.
  • Vaccinated birds still "catch" mareks when exposed. Your "healthy" vaccinated birds are carriers for life too and can spread it to and kill unvaccinated birds.
Thank you so much. This is terrific information. So is the vaccine a bad idea? According to Meyer’s billing, they got strain 3, and the necropsy did show tumors. I had it done at UC Davis’ San Bernardino lab.
 

Folly's place

Enabler
Premium Feather Member
10 Years
Sep 13, 2011
24,133
41,806
1,156
southern Michigan
Welcome!
The vaccine is very helpful, IF the chicks are totally isolated from exposure to infection for two weeks or so, to build up their resistance to the tumors that kill Marek's infected birds. Actual isolation is hard to do at home, because it's the dust, feathers, and dander that carry virus particles around an infected property.
It's possible that your chicks weren't vaccinated, if there was a mix-up at the hatchery. Something that would be hard to prove, but talk to the pathologist about it. Big hatcheries are processing thousands of chicks daily sometimes, and screw-ups could happen.
I'm sorry that you are dealing with this disaster!
Your birds will all be infected, and your property, so be very careful about biosecurity, and don't take this virus elsewhere. I hope that this spring's chicks will have a better outcome too.
Mary
 

ackie

previously jwehl // dogs & cats & squirrels oh my!
Nov 3, 2020
5,131
15,965
556
Atlanta GA
Thank you so much. This is terrific information. So is the vaccine a bad idea? According to Meyer’s billing, they got strain 3, and the necropsy did show tumors. I had it done at UC Davis’ San Bernardino lab.
My understanding is basically that you either want a wholly unvaccinated or a wholly vaccinated flock. Unvaccinated birds, if exposed to Mareks, are more likely to get sick and die, limiting the amount they can spread the virus, as opposed to vaccinated ones that are just asymptomatic spreaders living their normal chicken lives. If everyone is vaccinated, that's (in a perfect world) not going to lead to deaths, but the scientist in me says it helps the virus thrive. On the flip side, if your flock is unvaccinated, you will inevitably have more losses if Mareks does show up, but the virus will kill the hosts and eventually, with a lack of hosts, die itself.

(Though I'm not entirely sure how to properly clean an already infected environment of it.)
 

EggSighted4Life

Crossing the Road
5 Years
Apr 9, 2016
14,342
19,982
832
California's Redwood Coast
Hi all, has anyone else had an issue with chicks from Meyer Hatchery getting Mareks? I bought nine chicks in June and paid for Mareks vaccines. Now at six months, three have died. State lab necropsies state cause of death as Mareks! I’m heartbroken and scared for my other hens. Any info much appreciated...
Hi there, welcome to BYC! :frow

Very sorry for your loss and experience. :hugs

You've already gotten lots of great information. I want to say thank you so much for taking the time to try and get answers! I hope your remaining hens will thrive and they usually do once they get past they get past THIS point.. :fl

Another keeper (has a degree in avian science) I spoke with in the bay area that doesn't vaccinate either said fall is when it hit's his spring birds hardest... here in California. He keeps Cemani, and says some of the chicks fail due the stress/process of vaccinating presuming that breed appears to be bit more fragile than others. So for him.. it's a toss up to which is the higher reward value.

Breeders, who vaccinate all their birds.. may be spreading the virus without knowing it. That doesn't equal responsible breeding to ME.. and NPIP does NOT test for or report Marek's since layers in the industry are vaccinated and broilers are processed before onset. :(

but the virus will kill the hosts and eventually, with a lack of hosts, die itself
Not completely accurate.. I got Marek's diagnosed.. I lose a few young birds each year.. and those that don't succumb, thrive. I cull anyone at the FIRST symptom.. to keep live viral shed minimal. In other words, just like Covid.. the virus will kill SOME hosts and have ZERO effect on others. While another set of hosts may experience some symptoms like limping but appear to recover.

Marek's is said to be everywhere.. world wide. One gene was identified that gives resistance to Mdv.. I breed for resistance, vaccinated birds not welcome here, to hide the disease.. but it can exist in the environment for a very long time without a CHICKEN host... Though agree about letting it kill itself out, SOMEHOW.. oh.. by creating NATURAL herd immunity.. stop the virus when everyone left is genetically immune to it's SYMPTOMS. A complicated and complex subject, that will continue to learn about. Virology, poultry disease "morals"! :confused:
 

Folly's place

Enabler
Premium Feather Member
10 Years
Sep 13, 2011
24,133
41,806
1,156
southern Michigan
Our flock contains both unvaccinated birds hatched here, and vaccinated chicks from hatcheries. This has worked for us for 25 years, and so far we've been lucky to not have Marek's disease in our flock. I necropsy every bird who dies unless it's a predator attack.
If Marek's disease does arrive here, my unvaccinated birds will have issues that can be seen on PM, and then I'll be managing things differently, and no birds will leave here.
Mary
 

Cali_chkmama

In the Brooder
Nov 5, 2020
7
13
20
Hi all, has anyone else had an issue with chicks from Meyer Hatchery getting Mareks? I bought nine chicks in June and paid for Mareks vaccines. Now at six months, three have died. State lab necropsies state cause of death as Mareks! I’m heartbroken and scared for my other hens. Any info much appreciated...

We are currently experiencing a Marek's outbreak in our flock and it's devastating. Got chicks from Tractor supply unvaccinated. Kept inside brooder for about 5-6 weeks, and moved to outside coop.

We've been having one show signs every week or two and we had 15 birds to start. I have an older flock that is vaccinated and only lost a few here and there over the years to unidentifiable causes, but this is definitely textbook range paralysis mareks.

We got chicks from tractor supply and I stupidly forgot to ask if they were vaxxed. I believe the hatchery was in Iowa when I researched. Also the straight run was MOSTLY roos which was disappointing. I think the hatcheries toss more roos in to the chain feed stores just to get rid of them.

So now we've been removing and culling then as soon as they start to show signs. They are about 5 months old now. I'm praying we don't lose the whole flock, if anyone has any experience it input it would be greatly appreciated!
 

Poultrybonkers

Crowing
10 Years
Mar 22, 2011
4,306
2,906
426
My Coop
My Coop
A
We are currently experiencing a Marek's outbreak in our flock and it's devastating. Got chicks from Tractor supply unvaccinated. Kept inside brooder for about 5-6 weeks, and moved to outside coop.

We've been having one show signs every week or two and we had 15 birds to start. I have an older flock that is vaccinated and only lost a few here and there over the years to unidentifiable causes, but this is definitely textbook range paralysis mareks.

We got chicks from tractor supply and I stupidly forgot to ask if they were vaxxed. I believe the hatchery was in Iowa when I researched. Also the straight run was MOSTLY roos which was disappointing. I think the hatcheries toss more roos in to the chain feed stores just to get rid of them.

So now we've been removing and culling then as soon as they start to show signs. They are about 5 months old now. I'm praying we don't lose the whole flock, if anyone has any experience it input it would be greatly appreciated!
Tsc doesn't vac chicks it would cost them more then they sell them for and they sell males as str run
 

New posts New threads Active threads

Top Bottom