Moving Forward- Breeding for Resistance to Marek's Disease

[chooks4life]

The way I see most vaccines like Marek's or the human influenza vaccine is that it's a tiny more harmless exposure that signals an immune response so the animal or human immune system has a jump start before the real thing comes along. I don't see that as artificial. Vaccines are not doing the work of the immune system. It's not the vaccine that fights off a virus, it's the immune system that does all the work-hopefully earlier or faster . in viruses like Marek's or Influenza, the viruses grow faster than the antibodies against them are produced. The vaccine gives the immune system an early edge at producing antibodies.

I'm aware of all this, but obviously it's a point of view difference... I see it as artificial interference, you don't. Each to their own and all that. I understand your reasoning on it, though I disagree... Here's my reasoning on it, and of course you are free to disagree.

Natural infection with MDV, or early exposure to it, doesn't prevent them developing the tumors if they're that susceptible; however the vaccine does prevent that, in most cases. That's not a natural progression of immunity or resistance there, as it's assisting susceptible animals to survive it.

Because the vaccines contain artificially altered viral material, that's also, by definition, not natural, and the body does not respond the same way to vaccines that it does to natural raw virus... Again, quite a discrepancy there between what naturally occurs and what doesn't.

It's akin to the difference between the early inoculations for smallpox, and what occurs now. One example is infecting with live virus without altering it, just using it in very small doses, the other example is using altered strains or forms of the virus, rarely in live form.

Marek's is not the only virus that has been around for 100 years and still requires a vaccine. The playing field is unfairly tipped towards the virus winning. Meaning the virus multiplies faster than the antibodies are formed.

All true, but according to most of the research material I've been reading, the very vaccines themselves are blamed for its increasing virulence. (Though I do think the increasing virulence is due to multiple factors including natural evolution or adaption of the virus itself).

The fact remains that the vaccines are not a solution except in the somewhat short term preservation of susceptible animals. Over the long term, (meaning over a decade at the very least, over normal chicken lifetimes anyway), vaccination is not a real solution per se. It's damage control that appears to be causing damage in turn.

One day they may develop vaccines for MDV that are the solution and can utterly eradicate it, but right now they aren't a solution, and it does seem they're making the problem worse; that's still not a reason not to use them for pets, commercial flocks etc, I've got no objection to make to that; as someone's signature says (I forget who) 'we do the best we can with what we have and what we know'. Well, it's something like that anyway, you get the idea.

I think breeding resistance or vaccination is a choice depending on what your goal is. At this time I want my pets to live a long time.

I wasn't arguing that it's either/or, with only breeding for resistance or only vaccinating being the sole answer, I was addressing a few previous posts wherein it was stated that 'everybody should vaccinate'.

I fell that what might work as well as the vaccine is limiting exposure for the first eight months. Such as removing the chicks during the first 2 weeks of mom's passed on resistance for 5 weeks away, then again at 4 months for 4 weeks away. And give their antibodies a chance grow strong away from more virus concentrated areas of the property. I think I'd be willing to do that.

Good luck with that. I wish some research would center on what backyard breeders can do, in terms of limiting exposure or so forth, we need a more over-arching plan of attack against this disease. I never limited exposure with mine, but I do think it's quite likely America and the UK have nastier forms of many diseases we Aussies have, simply due to the population density, combined with the sheer prevalence of reliance on vaccines and antibiotics.

Best wishes.

 

[chooks4life]

Regarding that vaccine we discussed before (the one that does transmit the virus between vaccinated and unvaccinated birds in which neither had been otherwise exposed to the virus), some more info (from a biased source, admittedly, but still worth looking into):
Quote:
I've just realized how my posts are coming across to some, re: reactions such as 'jumping at ghosts' etc... When I noted that study before, it was as a curiosity, not trying to make out that it's a common or serious threat; I just found it interesting that so many people state it cannot transmit horizontally from vaccinated birds to unvaccinated birds, when in fact it can in some cases. I don't believe in stating absolutes that are incorrect, no matter how unlikely they are; if they're possibilities, they're worth noting.

I'm interested in collecting all info on the disease, especially when it comes to clarifying those aspects being repeated as universal truths when they are in fact not 100%. Just because something is very low likelihood, doesn't mean it should be stated to be impossibility; to do so rules out potentialities and closes minds to options that very well may require consideration, especially in those unexplained cases.

I'm not attempting to panic the masses, lol, just collecting info. In my search for the hard and fast truths about the disease, as per the commonly repeated 'laws' of Mareks', I'm not finding an awful lot of absolutes.

Best wishes.

 

[ChickCrazed]

I strongly suspect that you aren't experiencing Marek's in your birds; or, if you are, it is latent and you have a good strong flock with a lot of natural immunity. But that is just a gut feeling. I don't know your flock-- only you do.



Bingo. A lot of necropsy work is just a guess. Sometimes it is a more educated guess than others. Not to belittle necropsies... they are very useful tools in learning what is going on. But they are only one part of the puzzle. You need many parts in order to see the whole picture. And sometimes we never do get to see the whole darn thing.
When sending a bird for necropsy, if you suspect Marek's, it might be good to request that tissue samples be taken from suspect organs for further testing (this day it is mostly going to be PCR). Organ tissues and lymph tissues are going to be the key areas to look for the virus. Thymus, heart, sometimes liver, etc. Some places will charge extra for this. I am sorry that some folks have had a less than stellar experience with Perdue. That is unfortunate. CA seems to have a really good state program in place....


Forgive me if you mentioned, was the cocci detected via the necropsy, or did you diagnose (because of obvious infection/bloody stool/etc)? It's worth mentioning that many necropsy reports will find at least some cocci in the intestinal tract, since most adult birds will have small amounts as part of their natural 'fauna'. Like you mentioned, it is opportunistic and will turn into a full blown event if the chicken is weakened or gets a secondary problem (or the cocci is the secondary problem..!).


There might be merit to the UV idea... many viruses break down when exposed to sunlight. Herpesviruses are particularly resilient when in the environment because of the way they fully encapsulate themselves (darn them). I can't find any studies done on Marek's in particular (maybe you can!) but I have found studies done on other species of herpesvirus. They are not... terribly helpful to our application, I'm afraid. Unless I misunderstand them....

This one suggests that UV exposure seems to trigger a flare up of symptoms in humans that have Herpes simplex. It is unclear if the UV does something to the virus to help it, or if the UV does something damaging to the host (or host's cells) to cause the virus to take advantage of it. Some studies suggest that disturbances such as a wound, stress (we know this) or sun exposure reactivates the latent virus... http://www.progressivehealth.com/herpes-sun.htm

http://www.nature.com/nrneurol/journal/v3/n2/full/ncpneuro0401.html

Of note; this is suggesting that UV exposure benefits human herpes simplex virus when it has already infected a host. This is different than 'free virus' in the environment. I am unclear on if the virus, loose in the environment (not in a host) is adversely affected by UV radiation or not.

This is interesting. Not totally related, but it is insightful for those that might wonder why we can't kill the virus in an infected (human/animal). It is an older article but still interesting. http://www.reuters.com/article/2008/07/02/us-herpes-treatment-idUSN0229815620080702

It is also very important to note that UV light usually used for sterilization tends to be much more potent (has a higher energy level) than environmental UV light. This higher energy UV light is damaging to humans and animals alike, so one would need to use care to only do it when no birds were present (as you mentioned).

In short-- I am unclear on this. Does it help? Hurt? Do nothing?

Yes, Purdue was terrible. The first necropsy was mailed to the U of Missouri and they were great. Purdue was my only option the second time around because of the timing, I couldn't get an overnight mailing pulled off because of the weekend so I had to drive the body to Purdue. I requested Purdue save tissue and send it out for a PCR and they never did.

The pullet who died was displaying classic Coccidosis symptoms, puffed up and not moving. The necropsy found that she was thin and had large numbers of cocci in her, so it seems to support the diagnosis but who knows for sure. The cockerel that had the paralysis did have some cocci in his intestines but the crack staff at Purdue didn't specify how large a problem it was. My most recent death had Coccidosis symptoms, but I did not get a necropsy this time around since I have found out so little on the previous ones.

I will probably necropsy my next death again in the hopes that at some point I will find out something. I do agree that they can be useful but I would make sure you are prepared in advance on where you are taking them and make sure they are willing to run the tests you want.

 

[speckledhen]

Regarding that vaccine we discussed before (the one that does transmit the virus between vaccinated and unvaccinated birds in which neither had been otherwise exposed to the virus), some more info (from a biased source, admittedly, but still worth looking into):

I've just realized how my posts are coming across to some, re: reactions such as 'jumping at ghosts' etc... When I noted that study before, it was as a curiosity, not trying to make out that it's a common or serious threat; I just found it interesting that so many people state it cannot transmit horizontally from vaccinated birds to unvaccinated birds, when in fact it can in some cases. I don't believe in stating absolutes that are incorrect, no matter how unlikely they are; if they're possibilities, they're worth noting.

I'm interested in collecting all info on the disease, especially when it comes to clarifying those aspects being repeated as universal truths when they are in fact not 100%. Just because something is very low likelihood, doesn't mean it should be stated to be impossibility; to do so rules out potentialities and closes minds to options that very well may require consideration, especially in those unexplained cases.

I'm not attempting to panic the masses, lol, just collecting info. In my search for the hard and fast truths about the disease, as per the commonly repeated 'laws' of Mareks', I'm not finding an awful lot of absolutes.

Best wishes.

That's what this thread is for, collecting information. Never helps to bury one's head in the sand. We should know it all, no matter how obscure the information, no matter how remote the chance of something happening, you just add the qualifiers for the situation. So, though I certainly wouldn't want to hear that vaccinated birds could ever shed the virus to unvaccinated, doesn't help to ignore a remote possibility if it exists. It's one of those remotely possible, but not very probable things you just have to file away in the MD encyclopedia we're forming in each of our brains.

I realized that I had two vaccinated hatchery pullets in that main laying flock for a few weeks, raised here in the bantam pen with other chicks hatched here. I sold them as they approached laying age because I realized they didn't suit my goals and I needed to make room. Had to call Ladyhawk, who got two others I bought at the same time for her and gave to her, to verify my memory that they were in a vaccinated shipment. Going on the supposed known fact that vaccinated birds did not shed the virus, I made the purchase at the feed store the morning they got the shipment in from the hatchery of the Buff Orpingtons and New Hampshires. And they probably did not shed anything, being the remotest of possibilities. We need to know this stuff so keep posting!

 

[chooks4life]

That's what this thread is for, collecting information. Never helps to bury one's head in the sand. We should know it all, no matter how obscure the information, no matter how remote the chance of something happening, you just add the qualifiers for the situation. So, though I certainly wouldn't want to hear that vaccinated birds could ever shed the virus to unvaccinated, doesn't help to ignore a remote possibility if it exists. It's one of those remotely possible, but not very probable things you just have to file away in the MD encyclopedia we're forming in each of our brains.

^ THIS. Good wording, too, that's exactly what I'm getting at.

I find sometimes I forget possibilities just because a source I trusted worded them a certain way, and later on it almost comes as a surprise to recall they aren't absolutes, since that was how I remembered them due to phrasing. Important not to forget those possibilities, even if they're incredibly slight.

I realized that I had two vaccinated hatchery pullets in that main laying flock for a few weeks, raised here in the bantam pen with other chicks hatched here. I sold them as they approached laying age because I realized they didn't suit my goals and I needed to make room. Had to call Ladyhawk, who got two others I bought at the same time for her and gave to her, to verify my memory that they were in a vaccinated shipment. Going on the supposed known fact that vaccinated birds did not shed the virus, I made the purchase at the feed store the morning they got the shipment in from the hatchery of the Buff Orpingtons and New Hampshires. And they probably did not shed anything, being the remotest of possibilities. We need to know this stuff so keep posting!

Thanks, good to know you see a use for the random and unlikely sorts of info I'm finding lately. I was kinda wondering if I was merely being a nuisance. I do tend to get a bit enthusiastic about new information, lol.

On the topic of needing your recollections of those hens verified, don't you keep a livestock journal? I find them indispensable, though to be completely honest on the scale of necessities they tend to fall lower than they ought. It's easy to forget how important they are until they are suddenly utterly necessary, which realization tends to only occur in retrospect, as it goes... lol.

Best wishes.

 

[speckledhen]

Quote: No, not really. I post most stuff on BYC and go back to find it there, or in my Chicken Health picture folder. I don't have that many birds and haven't had that many issues over the past 9 years other than EYP and internal laying crud.

 

[Nambroth]

My position is to use what we have. It is not harmful, and helpful. When I till a yard, I like to let the hot late summer sun on it for a time before I cover it with hydrated lime. After the rain washes the lime in, I will plant it.
I like to let the sun in the houses. I believe in it. Because of our summer heat, I try to get as much of the morning sun as I can. I do not like a dark poultry house, or a stuffy house. Of course there needs to be shade to.
It would do nothing for an active infection of any kind. It certainly would not limit Marek's. What it can do is help with bacteria etc. that can become a secondary infection, and help limit exposure. A bird may tolerate a low level of exposure but succumb at a higher level.

I believe that a house that gets sun and good air flow is a cleaner house. I realize that this is elementary, but I emphasize it.

I apologize; I realize that my response above looks as if I am suggesting natural sunlight/UV exposure might be harmful. I also think that sunlight is beneficial, not only in its cleaning properties, but also for the general health and wellbeing of chickens and people alike. I was only trying to learn if intense UV radiation could help clean a poultry house of Marek's virus or not (and I couldn't find an answer). Again, my apologies.

 

[tridentk9]

 I try to set all of my housing up where sunshine hits every bit (less the ceiling) at some point during the day. I doubt this is helpful for an active infection of any sort, but I do believe it is important. Full spectrum lighting certainly has value, and the sun is free.

LOL-George you read my mind. I was thinking a brooder pen that could be taken apart when not needed, or at the least the roof off, specifically to let the sun in. While heat doesn't kill MDV the sun should help.

Taking apart the brooder pen should help get all the dander out and allow more complete use of disinfectant. Worth noting again and again is that disinfectants rarely work well unless the area is clean prior to application. Depending on the disinfectant, some have a limited life once diluted, others need a minimum contact time and some need rinsing.

And one of those thoughts in the middle of the night... Just because the chicken has Marek's Disease does not mean it has died of Marek's Disease.

 

[seminolewind]

I sent Fern for a necropsy, here's the preliminary;

Purpose of Test Diagnostic-Necropsy
Animal Information Chicken ; AVIAN - Chicken; Female; 5 Years

History Printed Suspected Marek's virus. Hen wasted and had paralysis + lethargic. Tx with safeguard wormer & sulfadimethoxine, Baytril. Euthanized my giving 30ml vodka and Ax.

Pending Tests Test: Virology Virus isolation avian system Number of specimens in which test results are pending: 1 Test: Molecular Biology Avian Influenza Matrix RRT-PCR Number of specimens in which test results are pending: 1 Test: Molecular Biology Avian Paramyxovirus-1 (APMV-1) Matrix RRT-PCR Number of specimens in which test results are pending: 1 Test: Histopathology Microscopic Examination Number of specimens in which test results are pending: 1

Lab Findings
Necropsy Specimen Test Name Chicken - AVIAN - Chicken - Female - 5 Years Animal-Dead - 1 Gross Exam Poultry (N.GEP) The body of a 5-year-old, Barred Rock chicken is submitted for standard necropsy on October 7, 2014. The chicken is in fair body condition with diffusely decreased subcutaneous and visceral adipose tissue. Autolysis is mild.

The subcutaneous and visceral adipose tissue is diffusely bright yellow. The lungs are diffusely mottled pink to dark red and are slightly rubbery. The liver is diffusely, massively enlarged, firm, and tan to yellow. The spleen is diffusely, mildly enlarged. The mucosa of the small intestine is multifocally red.
Icterus.
Page 1 of 2 - Preliminary (10/8/2014)

- Bronson Animal Disease Diagnostic Laboratory - Accession No: K1410399
Necropsy Specimen Test Name Lungs: congestion, diffuse, mild, acute. Liver: hepatopathy, diffuse, marked, chronic. Spleen: splenomegaly, diffuse, mild, chronic. Small intestine: enteritis, multifocal, mild, acute.


I guess she doesn't have any tumors, so far.
So far looks like liver failure and enteritis.
Thoughts?

 

[speckledhen]

Quote: Yes, this. For example, my hen had a massive reproductive infection, exacerbated by a worm infestation (my fault for not changing wormers). So, if she had signs of Marek's, did she die of Marek's or is it a sort of accidental finding incidental to a necropsy that showed she was dying from a massive infection that so many of my other hens have died from? And would she have died from latent Marek's without the stressors of infection and worms? Good point!

I have my best random thoughts as I'm coming out of sleep in the morning. Wish I could think as well when I'm trying to!