Moving Forward- Breeding for Resistance to Marek's Disease

[seminolewind]

Hey Sassy, I'm late on the welcome, but welcome!

If I'm going to lose one, it's usually spring or fall. I had 2 demises and 1 euthanized the past few months. The euthanized one was suspected Marek's wasting. The first demise actually turned out to be Aspergillosis. This last one so far looks like enteritis caused by Capillaria, but I haven't gotten the final report yet.

It is frustrating and upsetting. I've cried many tears.
It's ironic that if someone has always vaccinated their birds, and sells some, they could inadvertently pass Marek's along and they would have no idea. It's unfortunate that the vaccine prevents the side effects from killing the chicken, but does little else to help us understand or know if a chicken has it.

I would not worry about weak or susceptible birds, or vaccinating them and let them go on to breed more. Vaccination only protects against the side effects of tumors or tumors affecting nerves that may not be seen. A weak bird is a weak bird.

Breeding for resistance takes about 10 generations. I had 2 chicks with unvaccinated parents , hatched by an unvaccinated silkie who was in with the "Typhoid Mary" , in fact her daughter. They died at 8 months old. The same parents had another chick hatched by the silkie, and has survived so far. She's about a year old, and lives with 3 older unvaccinated birds.

Since the carrier silkie came to my flock, I have had numerous hatches without problem. I have also hatched batches of chicks for other people without problem. 3 years ago, I hatched 5 under a silkie, and 5 in the incubator, and added them in with the silkie. They all got paralysis, some gasping, no depth perception, one by one, were euthanized. All 10 gone.

Like what Chooks was getting at, those eggs must have come from a pristine 100% disease free place and they all died - I feel that if they had had some parental exposure, a few might have survived.

 

[seminolewind]

Random thought... What's the chances the vaccine is enabling non-resistant, but not completely susceptible (middle of the road type) birds to pass on their semi-effective yet semi-apathetic immune response to Marek's by preventing the fatal symptoms in enough of them for non resistant birds to pass on their weak responses? Seems quite likely to me.

In which case vaccinating would be a further cause of problems, not the solution it's touted to be by some (lol at the 'experts' who call vaccination a preventative); I think it should be judiciously used in some flocks and not in the rest of them. Used right, the vaccine could help preserve rare breeds, but further controls would be necessary to somehow ascertain that we are in fact breeding towards resistance, should that be something the owners of such flocks choose to do. It seems futile, saddening, and not a little crazy, to spend one's time as a poultrykeeper living in fear of a disease which isn't even fatal to many.

There's other diseases which are fatal to susceptible individuals but which the vast majority of the rest of the species is infected with and passes on, all without harm; one day Marek's may be the same. But at this rate it'll be brought about at the expense of rare breeds unless we figure out a better way to manage it, or a complete cure for it.

Chooks, scary picture!!! But I think all things are relevant. I agree, vaccinating does mask resistance. But I try to think of vaccinating a chick saves that chick from dying a terrible dragged out death. Nothing more and nothing less.

Since Marek's has known to have been around for 100+ years, and all scientists have managed to find a way to prevent 90% of vaccinated chicks from suffering the symptoms, but still be getting , exposing, carrying, spreading Marek's, I see it becoming an "every chicken" problem before I see it eradicated. So I feel the best thing I can do at this time is vaccinate a chick to prevent it from dying of Marek's.
I've cried over too many deaths to think about breeding for resistance. To get there I'd have to suffer even more deaths. My mental health would be at stake.

I do think I've seen something interesting happen. I hatched a batch of chicks for a farm last year. Lived here for 4 months before they went to live there. All are fine. In fact I got a rooster back at 6 months old and now he is a year old and fine. And they also got 4 (exposed)hens from me as well. I also gave a rooster to my neighbor a few years ago who is also fine.

It may be a correlation between a chicken's unvaccinated survival improving if , some time after hatching, goes away and comes back. Maybe it gives the immune system a chance to grow if given a break from bombardment. If you have an exposed flock and add an adult chicken, they seem to do okay . Something worth looking into, I think.

 

[speckledhen]

Hello speckledhen. Soooo sorry to hear that! I have actually read quite a few of your threads, and have always found them entertaining and well written! I also have gotten a feel (from your threads) on how much you love your birds and the biosecurity measures you take.

Dr. Davis is a nice man. I have talked to him face to face a couple of times, and I think he's of the "vaccination is the only way" camp, though I never had the fortune of reading a brochure! Did you get the MD result from a necropsy? Or is it a suspicion? I am of the thought that I am fine with having birds that are asymptotic/carriers, it's the symptomatic birds that I cull. I, like you, do not mollycoddle my birds. I have culled all the symptomatic birds from my flock, and the "death rate" has actually been zero for the past 2-3 months. Thankfully.

It is really frustrating. And upsetting. I can't tell you how many nights that it has kept me up...but I have to move forward! I don't want to give up, I don't want to start over with hatchery birds, and I don't want to mask genetically weak/susceptible birds. I hope things start to look up for you, and that you can find peace with it like I have!

Hope everyone else (and their chickens) is well too!

No, I have not had any birds taken for a necropsy, just a suspicious liver on a hen who died unexpectedly, first odd one I had ever seen with all the hens I necropsied over the years. And now I have another year old hen acting "off" very suddenly. BUT, no lameness, nothing of that sort. And I may not be dealing with it at all, but if you know me, you know I must be prepared and get my head on straight about it before I'm in the trenches with you, if it comes to that. I'm a researcher by nature, just have not spent the time to research this one, but it's time to do that. So, I have been speaking with Dr. Davis by email today. I do think you're right, that he's a vaccination kind of guy. I do not believe I could go that route.

I, like you, do not want hatchery stock and I do not want to mask symptoms of weak birds, either! How many times on this forum have I told someone not to give a new bird in quarantine antibiotics? It might mask symptoms of an underlying problem you MUST see! So, you and I are very much on the same page. Right now, I'm just figuring out what page I'm on with this disease. It was rather confusing to me previously, the traditional vets saying one thing, the folks in the trenches saying something else. It's maddening that you can be so careful, (and to me, it's still right to be careful in reasonable ways) and it is all for nothing, at least as far as Marek's is concerned.

I am an advocate of culling respiratory disease carriers because I feel that contagious respiratory disease is a different animal than Marek's. You can't really breed for resistance with those respiratory diseases, IMO. Think about it-they do not stay in the soil permanently like Mareks does, you can start over, and fairly easily. With Marek's, you are fighting a losing battle if "burn the house to the ground" and yet, the ground itself is still there. I am just beginning to see that in this situation, breeding for resistance may be the only way to go that will ever truly work. I will not just drop all biosecurity measures because mine are not crazy insane, just reasonable and, to me, right and normal. I don't want to fight everything, don't want to just open the door to it all and give up.

I've read that Mareks is a disease of younger birds, while LL is for slightly older birds. Most of mine are positively ancient by either standard and have lived on this property since hatch so if it's here, I'd say most would probably be resistant to whatever is here.

As Karen said, I have had a closed flock. Many years ago, I bought that one rooster who had favus, lice and malnutrition but nothing else. He was in quarantine for 5 weeks before adding him to my original flock. Then a friend whose flock had never had even a sneeze gave me an 8 week old EE hen she hatched from a breeder's eggs who was working on a new Ameraucana color variety. She was also in quarantine for weeks-that is my 6 1/2 year old June. No other birds have ever been added that were not hatched here, either from NPIP breeders or from my own birds or direct shipped to the feed store from the hatchery. I've only been to two shows over the past 9 years, just to walk through and look, not to show my birds. Like sassy, if Mareks is here, I would have no idea where the heck it came from. I can say I did all the things I knew to do to keep my birds safe. If that wasn't enough, my conscience is clear and we move on. So, thank you folks for letting me join in your conversation.

Sassybirds, what part of GA are you in, if I may ask?



Karen, this is very interesting:

Quote: And what was this farm's take on Marek's? I'm wondering what happens if eventually, it ends up here. I cannot let any birds go from here again, can I? I can't let chicks hatch because I can't keep all of them. This is one part that bothers me a great deal. I rarely hatch now except with a broody (and they insist or they starve themselves so much).


And you said this, which I do relate to, having lost SO darn many to internal laying issues:

Quote: Not Mareks, but I understand this so well. Hugs to you, friend.

 

[chooks4life]

Chooks, scary picture!!! But I think all things are relevant. I agree, vaccinating does mask resistance. But I try to think of vaccinating a chick saves that chick from dying a terrible dragged out death. Nothing more and nothing less.

Since Marek's has known to have been around for 100+ years, and all scientists have managed to find a way to prevent 90% of vaccinated chicks from suffering the symptoms, but still be getting , exposing, carrying, spreading Marek's, I see it becoming an "every chicken" problem before I see it eradicated. So I feel the best thing I can do at this time is vaccinate a chick to prevent it from dying of Marek's.

I don't blame you or have any disagreement, 'to vax or not to vax' is a very personal question, depends entirely on individual circumstances. If I kept rare breeds or only pets I'd probably vaccinate.

While I like some purebreeds and believe in the importance of conservation of them, I don't envy those in that position. Mongrels have many benefits for me when compared to the alternatives. One of the many benefits is that they're descended from generations of unprotected birds; they're not bulletproof but I sure do sleep easier at night than some folks! ... Those folks definitely have my sympathy though.

I've cried over too many deaths to think about breeding for resistance. To get there I'd have to suffer even more deaths. My mental health would be at stake.

I do think I've seen something interesting happen. I hatched a batch of chicks for a farm last year. Lived here for 4 months before they went to live there. All are fine. In fact I got a rooster back at 6 months old and now he is a year old and fine. And they also got 4 (exposed)hens from me as well. I also gave a rooster to my neighbor a few years ago who is also fine.

It may be a correlation between a chicken's unvaccinated survival improving if , some time after hatching, goes away and comes back. Maybe it gives the immune system a chance to grow if given a break from bombardment. If you have an exposed flock and add an adult chicken, they seem to do okay . Something worth looking into, I think.

That is interesting, especially since from what I've read, Marek's can affect any age birds but has a strong preference for pullets and those around 6 weeks and onwards, within the first year of life, whereas they all seem stronger after that, or possibly it's just that those most susceptible die within that period. Interesting to think perhaps they can survive if not exposed within that time period.

Best wishes.

 

[speckledhen]

Everyone on both of the vaccination sides has some good points. I have not made any set-in-stone decisions about what I would do if it reared its ugly head here, but I want to get my head on straight as soon as possible.

The one thing that bothers me about vaccinating from the get-go, the first birds you get and all after that, is the vaccine doesn't stop the disease, only the worst ravages of it. So, you sort of have an "ignorance is bliss" situation, not knowing you have Marek's positive birds and you are buying and selling over time, with the positive, yet asymptomatic, birds shedding the virus all over the place. Unless, I am mistaken, and vaccinated, yet positive, birds cannot shed the virus? I didn't see where the vaccination would/could stop the positive birds from shedding. I'd like to get that part correct. Of course how would you know not to sell your birds, how would you know they even had the virus, if they did not have symptoms? You couldn't.

sassybirds, here is Dr. Davis's brochure in it entirety since you don't have it. Sorry about the form. He sent it to me in a word doc but I only have WordPerfect on my computer so DH had to convert it and email it back to me:


Quote: Some of this bugs me a little, though--to reduce stress, keep them not too hot or too cold? I don't even regulate my own house temperature to that degree.

Plus, the last suggestions are what I've always done with my flock and no symptoms up until this point, though we know that the disease is certainly in our state, so does that mean I could have an entire flock of infected HAPPY birds?

Also, he says in this article, "to prevent infection, vaccinate....", but we know that vaccination does not prevent it at all, so I think the wording is not exactly the way it should be, but maybe that's what he meant to say? He's been very nice in corresponding with me through emails, I must say. I was worried when Dr. Bohanan wasn't available because you never know with a new guy what personality you'll encounter. But, he's been very helpful.



I pressed him for a further explanation of the vaccine protecting against the actual virus or just tumors and this is his reply (I think I have it now)


Quote:
to me

No, the vaccine prevents birds from ever being infected in the first place (not just the tumors). However, it has to be a cell-associated vaccine that is stored at 170 degrees below zero (in liquid nitrogen)… and it has to be given at day-of-age, at the hatchery. And it has to be given within 20 minutes of thawing/mixing it. You can purchase Marek’s vaccines from Animal Supply houses, but this is not the same vaccine that they use at the commercial hatcheries (because nobody has liquid nitrogen on hand in their home to keep it that cold). The vaccine that you can buy, yourself, is better than not vaccinating at all. However, it does not provide the protection that the vaccines used at the hatcheries do.
So, chicks vaccinated at the hatchery with the type of vaccine they use will not likely get Marek’s. The only way they would is if (1) someone at the hatchery did not handle the vaccine properly; or, (2) the Marek’s virus circulating in a flock is one of those highly pathogenic strains that the standard vaccines will not protect against.

I hope this explains it.

 

[seminolewind]

Normally, when one is exposed to a virus, the body builds "an army" to fight it off. If a bird is exposed to Marek's, the army does not get built Fast enough. So the vaccine is an attempt to "trick" the body into building that army before it's ever exposed to the real thing. (Immunity or resistance)
Same thing as the flu vaccine. It's exposure to a disarmed virus, so that the army (immunity/resistance) is already built when the real thing comes along.

Marek's is spread by bird dust and dander. If one has it, chances are the rest of the flock has it as well because dander is everywhere.

Younger chickens (under a year) tend to present with paralysis. Older chickens tend to present with wasting. The most common age to show symptoms is 6-12 weeks. Most common. Any age can die from Marek's. My first chicken was 18 months old when exposed and displayed all the classic symptoms: paralysis, wasting, grey eye, loss of depth perception (can't aim and pick up food), finally loss of neck control. The vet did not see any tumors, therefore he was not diagnosed properly.

The symptoms you hear the most about are the classic symptoms ; the easily recognized. Absence of those symptoms does not mean that a bird does not have Marek's.

Marek's exposure is any bird exposed to a bird carrying the virus. The exposed bird becomes a carrier as well. Whether or not they are vaccinated, birds that are exposed can carry the virus and pass it to others. Therefore, a vaccinated bird can still carry and give Marek's to others if the vaccinated bird has been exposed to Marek's. But the bird did not get the virus from the vaccine.

Fighting Marek's is like fighting a ghost. Everything said about Marek's is in terms of most common, likely, unlikely, probably, etc. Paralysis can be caused by other ailments as well, such as a vitamin deficiency, botulism, Aspergillosis.

Since the hatcheries have a better vaccine than the ones we buy, many people quarantine vaccinated chicks for longer periods than the 2 week minimum.

I've also found that some of my Marek's vaccinated (by me) and exposed youngsters tend to have poor resistance to common bacteria, such as Coccidiosis, eye infection, enteritis.

The vaccine does not prevent Marek's. It prevents the tumors and nerve damage caused by the virus.

Yes you can have an entire flock of happy birds that carry the virus. In fact, birds with paralysis or wasting still have a smile on their face (seem to behave normally) Most likely not huddled and puffed up standing in a corner. Marek's has nothing to do with NPIP testing.

 

[speckledhen]

Quote:

You expressed my thoughts exactly with the "fighting a ghost" comment, Karen. I was becoming frustrated and looking for the words and you found them for me.

I mean, what am I going to do? Say, well, my birds seem healthy, but everybody is talking about Marek's so I'd better put one down to have tested!? Who can fight a ghost?

Seems to me that, aside from any outer signs, other things can mimic internal organ damage of Marek's, like e coli, staph, LL, Avian Vibrionic Hepatitis or maybe even a poison that gets into the system to kill the liver and subsequently, shuts down the bird's entire system. So, I'd guess until and unless there is reason to worry about it, we have to just keep on keeping on and cull suffering birds as they happen and if it's suspicious, have a necropsy done. Thankfully, so far, my only long-suffering hens have been the ones with EYP/salpingitis/internal laying infections. Stupid hatchery crap, I really hate to think of going back there if worse came to worse.

Quote: Absolutely right! I wish I could get this through the heads of the folks who think that NPIP means disease-free. It does not!


Quote: This is what I've always read. But, Dr. Davis just told me that the "good" vaccine, the cell-associated one, does prevent it, when properly given at the hatchery, unless it's one of the particularly virulent strains. See, even the veterinarians have said different things about it.

 

[tridentk9]

Seems like I read that the different strains of Marek's tend to have different symptoms. Another comment elsewhere was that many birds get another virus first.

Here we go. Infectious Bursal Disease fits many of the symptoms brought up. It also gives Marek's and other diseases an in. Ahh- the link ... http://waddl.vetmed.wsu.edu/animal-disease-faq/infectious-bursal-disease

 

[speckledhen]

Seems like I read that the different strains of Marek's tend to have different symptoms. Another comment elsewhere was that many birds get another virus first.

Here we go. Infectious Bursal Disease fits many of the symptoms brought up. It also gives Marek's and other diseases an in. Ahh- the link ... http://waddl.vetmed.wsu.edu/animal-disease-faq/infectious-bursal-disease

One good thing about this IBD that I did read was this:

Quote: Thank goodness for that, at least.

 

[seminolewind]

The strains of Marek's are virulent, very virulent (VV) very very virulent (VVV), etc.

The vaccines that the hatcheries are 3 different vaccines in one including a Turkey Marek's virus, and an altered most common chicken Marek's virus, and one highly virulent altered virus. The vaccine we commoners get is just the Turkey Marek's virus.

The difference in symptoms has to do with where in their body the virus strikes; legs, brain, respiratory and other nerves, eye, etc. It will probably follow the path of least resistance.

I haven't seen any have another virus first. What I have seen is that some exposed birds are more prone to having coccidiosis .

No vaccine prevents a chicken from getting Marek's virus. Vaccines will only give better or not better Protection against Development of the tumors/nerve damage. The older a chicken is the more likely they become more resistant.

I, and others keep a support group going, and share knowledge and experiences. There is life after Marek's. It's just doing some things in a different way. My chickens are pets. I will continue to only add vaccinated and quarantined birds. I have a very hard time with them dying and will not expose myself to more death than I need to. I had to stop hatching because I ended up with 7 roosters that can go to be food, but who wants to eat a skinny bird? I have 12 nice healthy vaccinated hatchery hens, and 5 I've vaccinated, so half of mine are vaccinated and about half are unvaccinated and older but 2 are a year old. So I'm having a lull.

Changes we make? Adding only vaccinated and quarantined day olds. Not giving away any birds. (The farm I hatched for had no chickens and was informed) . Being careful not to bring any bird stuff to other homes. I had picked up some geese at a friend's house last year. Hubby and I showered and changed our clothes right before we left. And we did not go near her chickens. My hatchery chicks went into an unused spare room and we gowned and gloved for 3 weeks to enter because surely it's all over my house.

If you want to sell chicks, incubate at a friend's house. I shared some hatchery chicks with someone and she met me at the door prior to me opening the box and she picked the ones she wanted. Or sell eggs. Or buy them.

Anyhow. Living in fear does not change things. Be happy with the chickens you have. Never stop trying to find a different reason a chicken died. Think about your flock history. If Marek's is in your flock it is likely that at least one will be symptomatic. If in doubt, have a dead chicken tested . Or send live chicken blood and some feathers to Texas A&M for PCR testing.

Cynthia, I learned biosecurity from you 7 years ago. I broke my rule once

. But with your past and current practices, it's More likely that you don't have it. If you have it, surely one will tell you in their own way. Worrying does not help matters and takes away from the pleasure you have from them now.