# Mareks and MG



## Maryellen (Jan 21, 2015)

So if the only birds tested for mareks were the only ones vaccinated for it does that mean its a false negative?

And the MG... well... a whole issue in itself


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## seminole wind (Aug 22, 2015)

I think the lab test distinguishes between the disease and the vaccine. And Marek's vaccine would show no tumors compared to the disease.

With the mg, I think it's a matter of getting mg-free eggs, and eggs from a Marek's bird would not be spread thru an egg.


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## Maryellen (Jan 21, 2015)

The one hen died of worm.overload. 
No one is showing any symptoms still. And i really dont believe i have mareks here. The lab work doesnt say vaccine or otherwise so how would i know?


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## Maryellen (Jan 21, 2015)

The one necropsy said no tumors just worm overload.


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## dawg53 (Aug 25, 2015)

If one bird had worms, most likely they all do. Wasnt this way back ME?


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## Maryellen (Jan 21, 2015)

I still am on the fence . No chicks died here in all the years ive been hatching. Everyone who bought my chicks say they are alive amd healthy and pumping out eggs.


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## Maryellen (Jan 21, 2015)

I have right now 12 easter egger chicks in my living room . I got them 4 weeks ago. I took sand from the coop and put it in a dust bowl for them. From the supposed infected coop with the bredas. No chick has died in the past 2 weeks from the sand from the coop. 
Now wouldnt they have died if i had something in my adult birds once i brought the sand in?
Thats the confusing part. So if the bredas were vaccinated by the breeder and the ameracaunas too from the other breeders then they would show false positive


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## dawg53 (Aug 25, 2015)

Sorry, I cant help you with Marek's. That's Karen's ball game. However if it were MG, I seriously doubt chicks would even survive.


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## Maryellen (Jan 21, 2015)

Thats what i think dawg, these 12 chicks should have died when i brought the sand in from the breda coop. I took it off the coop floor, picked out any dried poop and gave the chicks a pan of sand to dust bathe... all 12 .... not one dead chick. Its been 2 weeks... plus im not doing any changing of clothes, shoes or amything. Plus the dogs go in the coop and run so they would carry it too.. these chicks are growing like weeds.


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## Maryellen (Jan 21, 2015)

So if the bredas were vaccinated for both they would test positive for both, just like dog vaccines .


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## Steinwand (Sep 23, 2017)

I'm extremely interested in Mareks. How do I keep it out of the flock and if i can't what does that mean also what are mareks ramifications how do I vaccinate, and if I do have mareks or my flock gets it in the future what does that mean for NPIP certification


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## Steinwand (Sep 23, 2017)

I may have overlapping questions please forgive


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## Maryellen (Jan 21, 2015)

Npip is for testing for avian influenza and pollurum. To test for other diseases costs extra.
Seminolewild is an expert on mareks so i cant help.
MG is a respiratory disease that comes in from wild birds and infected chickens. Im just learning about both so i dont know much.


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## Maryellen (Jan 21, 2015)

If your birds test positive for any diseases you lose your npip status


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## seminole wind (Aug 22, 2015)

My unvaccinated chicks were symptomatic starting from 6 weeks to a year. Most of all paralysis and/or wasting. They looked like they were eating but weren't really picking up anything. All appeared happy. Some chicks had panting or grey eye. It depends where the tumors attack.

The only way to avoid Marek's is to keep a closed flock. Only eggs you hatch yourself from anywhere or hatchery chicks. The vaccine does not protect from Marek's exposure and exposed birds will carry Marek's vaccinated or not. The vaccine prevents the tumor growth and symptoms.

You can vaccinate yourself when chicks are a day old. Then the chicks have to be quarantined for at least 3 weeks. The vaccine works by it being a kind of sterile exposure that won't give them the illness but the immune system thinks it's real and builds antibodies that protect the chick. As far as I know the necropsies do tell the difference by first having tumors present on organs and a positive exposure.


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## chickenqueen (Jan 9, 2016)

ME,have you thought about having them tested by a different lab such as by students at an university or private lab that does their own tests?I wouldn't put all of my eggs in the state basket.Don't say anything about the mareks or mg and see what they come up with.


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## Maryellen (Jan 21, 2015)

CQ thats exactly what im going to do. Im going to have a different vet test one of the bredas and see what it comes back as.


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## Maryellen (Jan 21, 2015)

If anyone knows how to read reports ill email the results from the georgia lab. I cant understand some of it


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## seminole wind (Aug 22, 2015)

I'd like to see it [email protected]

You can always call the lab and ask about Marek's testing and true positives vs false positives.


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## Maryellen (Jan 21, 2015)

Ill email you karen thank you!!!


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## seminole wind (Aug 22, 2015)

Here's an article by some UK magazine. I know the testing done here is pcr testing.

Differentiating field strains of Marek's disease virus and live vaccine virus in the commercial poultry house is essential to effectively control the disease, as Poultry World discovers

Vaccination has been successful in providing lifelong protection of chickens against Marek's disease since the 1970s.

But it doesn't stop them from becoming infected with virulent strains of the herpesvirus that causes the disease.

The ability to detect and measure the vaccine and the virulent virus, and to distinguish between them, is important for monitoring and thereby maintaining effective protection.

"There are several important reasons to be able to make this distinction," says Stuart Andrews, poultry technical manager of Zoetis.

"We need to be able to confirm effective administration and replication of the vaccine virus, and to identify any causes of poor vaccination uptake. It is also helpful to be able to confirm the presence or absence of virulent virus, and to monitor its levels in the poultry house environment."

*Different strains*

Marek's disease is highly contagious and caused by virulent serotype-1 strains (MDV-1) of the herpesvirus.

Three closely related strains: MDV-2, herpesvirus of turkeys (HVT) and CVI988/Rispens - which do not cause disease in chickens, have for more than 40 years been used as live vaccines against Marek's disease.

If the chickens have been vaccinated using MDV-2 or HVT, real-time quantitative PCR testing can be used to easily distinguish them from virulent MDV-1 strains, because they are genetically different.

However, if the chickens have been inoculated using CVI988/Rispens vaccine, it is very difficult to tell the difference because the vaccine is genetically so similar to virulent MDV-1.

Laboratory tests currently involve a lengthy two-stage procedure and are frequently inconclusive.

*New tests*

At the Pirbright Institute's Compton Laboratory in Berkshire, researchers have been collaborating with Zoetis over the past 12 years to develop a new method to distinguish and measure CVI988 vaccine and virulent MDV, targeting a specific area of the virus genome.

"There are major advantages of the new quantitative PCR tests which we believe will help the poultry industry counter the constant challenge from Marek's disease," said Dr Andrews. "While there are two assays run on each sample - one detects CVI988 vaccine and the other virulent MDV field virus - each test is rapid and easy to perform.

"Each test is highly specific for the target virus, so both the CVI988 vaccine virus and virulent MDV field strains can be quantified, allowing comparison between samples."

Dr Susan Baigent, who developed the test, said a major difficulty in tackling Marek's disease is the ease with which the virus is spread.

"Although the vaccine protects the birds, it doesn't stop the virulent virus replicating in them and being shed from the skin and feathers. Hence the virus can readily contaminate the litter and dust within the poultry house, and then spread to other houses through being carried on the air, on people and even vermin.

"Levels of vaccine and virulent MDV are greater in the feather tips than in other chicken organs. Feather tips are easily collected from young chickens, and we can readily isolate DNA. Feather samples are much more convenient than blood or spleen samples. We can also measure levels of vaccine and virulent MDV in samples of poultry house dust, which gives an overall picture of the level of the vaccine and virulent virus for the whole flock."

The new technique, which is four times faster than a conventional test, is now being used at the Poultry Centre of Excellence which Zoetis opened at Torce in Brittany in 2013, providing PCR diagnostic facilities for customers in Western Europe.


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## Maryellen (Jan 21, 2015)

I have to scan it tomorrow i cant find the email.report i know i printed it


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## seminole wind (Aug 22, 2015)

This is from 2017.

http://www.oie.int/fileadmin/Home/eng/Health_standards/tahm/2.03.13_MAREK_DIS.pdf

Always look for dates on articles. I've seen many on line that are from the 70's and 80's and not up to date. If you look in the references at the bottom you can see that the contributors are all fairly recent (newer than 2005 is what I call recent.)


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## chickenqueen (Jan 9, 2016)

Good luck,ME!!!


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## Maryellen (Jan 21, 2015)

Karen i emailed you this morning


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## seminole wind (Aug 22, 2015)

Hi I got it!
I forgot to add that if a chicken has mg or marek's, many die from opportunistic bacteria, fungus, etc. because their immune system is compromised. 

I should also look in to what ailments can be identified by blood specimen only.


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