Dumb Marek's Question

[LarryPQ]

OK--So I have the unfortunate happenstance to remember most things I read, which means things can get jumbled since no one in the Lareebrain is actually filing anything.

In my research about Marek's, I recall coming across the idea that keeping a turkey who has had the turkey marek's will help prevent deadly lesion outbreaks within the chicken flock.

There was plenty of reasoning behind the thought process, but scientifically speaking it rubs me all the wrong way. Too many variables.

Malarkey or possible low-tech solution?

 

[CheerfulHeart2]

Let's discuss the science then. My 30 sec search on Marek's tells me it is a virus. It seems like it infects both Turkey's and Chickens. So, i suppose it is possible that a turkey with antigens would be resistant to reinfection, but what reason is there to believe that the antigens from the turkey would transfer to the chickens?

 

[LarryPQ]

The reasoning was thus:

The Marek's vaccine is really the turkey herpes version. Like giving people cow pox for small pox.

Marek's is transmitted via dander.

So if the infected (or vaccinated) turkey was in with the chicken flock, the virus would be shed via the turkey dander, and the chickens build up a resistance, just as if you had poked them.


ETA--see? a little to close to SOUNDING true to be true.

Here is a quick synopsis that should be mostly true:

Marek's is a form of herpes, which can present itself in three forms. #3 is the most virulent, and the most deadly. It creates the lesions on the brain, which cause the "drunkenness" . It also has auto-immune symptoms, which make the sick bird more susceptable to other diseases: so a chicken dying of mareks may often be KILLED by something stupid and treatable like cocci.

Once a chicken exposed to Marek's, it is always a carrier. The herpes is transmitted via the shed dander. Vaccinating your entire adult flock once the disease has presented----is a waste. Your chickens will either live, die, or get one of the 2 lesser forms (lesions in the throat, or lesions in the eye--gray/inconsistant iris). The best you can do is make SURE to vaccinate & quarantine any new birds coming in. Otherwise you are on complete flockdown until all your current birds have passed.

Mareks can also live in the soil for up to (I read recently) 65 weeks.​

 

[edselpdx]

Quote:
I haven't done the research to know if the Marek's vaccine is a live (disabled virus) vaccine or a killed virus vaccine, but that doesn't really matter.

Here's the problem: Immunity to a virus is caused by exposure to the virus (either dead virus or live virus which has been altered in a lab so it can't reproduce and infect the animal) in the vaccine. The turkey's immune system reacts to the "shape" of the virus and then develops a "memory" for that virus; the turkey is never infected with a live virus that can reproduce or be shed in the dander. The next time the turkey comes into contact with a real live virus particle, its immune system already 'recognizes' the virus and kills it before it can reproduce. So, the turkey never sheds virus particles in its dander. If it did shed real live virus particles, it would infect, rather than immunize the chicken, whose immune system has never "memorized" the "shape" of the virus in the first place.

Vaccinations aren't infectious, but Markek's is.

If you have two or three children, you wouldn't just vaccinate the oldest one and wait for the immunity to "spread" to your other children, right? Same goes for your turkeys and chickens.

 

[CheerfulHeart2]

This is an interesting discussion.

 

[LarryPQ]

edselpdx-- You have hit the nail on the head! This is why I have been so bothered by the idea a vaccinated turkey would be good for the flock as a whole.

So what about a non-vaccinated turkey, who has the turkey version of Marek's? Then the virus WOULD be replicating, and being shed in the dander. This situation would be "ok". We WANT the chickens to get the turkey version, since it is not fatal to the chickens.

 

[tls_ranch]

I heard that old time breeders of Seabrights raised white turkey poults in with their seabright chicks to prevent mareks. Apparently seabrights have little resistance to mareks and this was probably before the mareks vaccine was available.

I believe the turkey poult would have to be infected with the turkey mareks to "vaccinate" the chicks by close contact. The chicks would have to have time to develop immunity before exposure to chicken mareks or it wouldn't work. So, to make the turkey thing work you would need a sick turkey or at least one that is a carrier of the turkey mareks.

 

[edselpdx]

If turkey Marek's does not sicken chickens (like cowpox is to smallpox in humans), then yes, you would theoretically have to have a turkey-Marek's infected (not vaccinated) turkey to "immunize" your chickens. Sounds like a chicken Marek's vaccine is a whole lot easier on both you and the turkey.

 

[High Roost Ranch]

Ever since we had poultry when I was a kid, and again these last 10 yrs as an adult, turkeys have always co-mingled with my poultry. I do NOT vaccinate my young birds for Mareks, I never have. To my knowledge, I have never had a diagnosable Mareks case in my poultry. My chicks are raised indoors, then are moved outdoors at about 6 weeks of age in the warmer months. When they are about 4-5 months old, I move them to ground pens usually. I don't know if what I'm doing is right or wrong, but it's worked for me. I'm a believer in natural immunity.

 

[edselpdx]

Quote:
Congratulations on never having had known Marek's in your flock. I doubt that has anything to do with natural immunity, but rather luck in not having your birds exposed (or possibly having an infected turkey as described above). Vaccines CREATE natural immunity. Exposure to a small dose of the non-infectious Marek's virus in the vaccine stimulates the birds natural immune system; that is how vaccines work. The problem is that exposure in chickens to "wild" chicken Marek's virus doesn't create chicken immunity, it causes chicken disease. Marek's can be a chronic carrier condition, or it can kill your flock. Once it's in your flock, any survivors will pass it to all other chickens who arrive, and take it with them when you sell the animal, not spread immunity like the above-hypothesized turkey.

I have chickens. I don't have any turkeys. Vaccination was the right choice for me.