Quote:thats a great chart, thanks for posting it.
I feel like I am too much a newbie to mareks - just since Oct this year and am still learning too much to feel confident about saying anything regarding your situation.
there is confliction with info .. im still trying to work out some of the info that's on this chart. like the Cytology of tumors or category of neoplastic lymphoid cell T or B something that was not mentioned on my report and reading it makes my eyes cross.
There is a lot of conflicting symptoms with Marek's. To have a bona fide Marek's positive, a pathologist needs to look at the bird's symptoms and flock history, examine the tumors, and send blood/tissue for a pcr. A pcr takes a portion of dna that's otherwise too small to test and it multiplies enough from the sample to get enough to diagnose.
My last hen was a one year old hatchery vaccinated BO, who must have been skinny under all those poofy feathers. I just found her dead one morning. No warning. I do think she was always slightly paler than her sister, but didn't think much of it. She had tumors but None in her Sciatic nerves ! Now according to some , it matches LL much more than Marek's. But the pathologist said she had to wait for the pcr to come back before she could have a diagnosis because the tumors from Marek's , LL, and 2 other viruses are very much alike.
The biggest problem in diagnosing Marek's without a necropsy is that Marek's doesn't play by the rules. The symptoms are "most likely" or "least likely". My first one was an 18 month old rooster than got paralysis one day. He must have had some leg weakness weeks before because I was led to believe he would wait for me to tuck him in.-Not!. He lived on my patio and the paralysis made it's way up to his neck. His left eye got gray. He sat on occasion with one leg forward and one back but not always. Then he lost his depth perception and couldn't connect to the food. I had him put down and cried every day all thru Christmas. The other 9 silkies were fine and lived long.
My next one was a 2 year old hen who I found with a "broken leg" and casted her and put her in a sling, She wasted, ate little, and lost her depth perception. I euthanized her. Within the next week I lost 8 six week olds , one each 5-7 days from paralysis and loss of depth perception and neck control. The first chick I thought broke her leg (?). The second one told me that there was a problem here.
Long story short,symptoms are not the only thing to consider. You need a flock history, a necropsy, and some dna. That's the confusion about Marek's symptoms.
Now you can add to that all the illnesses your vaccinated chickens can die of because Marek's exposure alone has weakened their immune system.