Suspicion of Marek's Disease- Now what do I do?

[rdetraz]

Howdy! I suspect one of my hen's has the ocular strain of Marek's disease. She has been exhibiting signs of blindness for the last two weeks, and her pupils and irises are extremely not normal. My question is do I cull her or let her be? I have a new shipment of chicks coming today who unfortunately were NOT vaccinated. None of the rest of my adults show symptoms, but I really don't want to lose my entire flock plus all of my new babies.

 

[EggSighted4Life]

Hi, welcome to BYC!

Sorry your gal is having trouble.

If you decide to cull or she passes... getting a necropsy is the only way to confirm or debunk Marek's.

Best info I have seen on the subject...
https://www.backyardchickens.com/articles/the-great-big-giant-mareks-disease-faq.66077/

Links to help if you decide to get a necropsy which is often affordable or free to back yard keepers...
https://www.backyardchickens.com/threads/how-to-send-a-bird-for-a-necropsy-pictures.799747/

https://www.aphis.usda.gov/animal_health/nahln/downloads/all_nahln_lab_list.pdf

Theses are links for the US. Adding your general location to your profile can help others to make the most relevant suggestions possible at a glance without having to ask first.

How old is your gal?

I personally do cull for suspected Marek's. While others may have been exposed already... an actively ill bird is actively shedding more virus among my flock. Less exposure is still less to me. In addition to that I feel as though all illness and disease attack the weakest link first and so I consider them a vector to other possible issues. There are some peeps on here who DO support and keep their Marek's birds alive. It's a personal choice. Consider if the bird is still having a good quality of life and also how it effect YOUR quality of life. Do you have the time or energy or desire to care for a special needs bird?

Please note, Marek's vaccinated birds NOT welcome here... to essentially hide AND spread the disease of they do catch it. The vaccine does NOT stop them from getting MDV but only lessens the symptoms. That makes it a deal breaker for me.

Some people who KNOW they have Marek's at their place and cannot afford (emotionally or otherwise) any loss of life should get vaccinated birds. There has been one gene identified that does provide resistance to MDV... I choose to breed for resistance which is not an option for everyone.

I know the first encounter with Marek's is scary! But it doesn't have to be as bad as people make it out. Hang in there!

The key to me with your new chicks and existing flock... nutrition, not over crowding, internal and external parasite control.

 

[Eggcessive]

Welcome to BYC. Could you post pictures of the eyes of the hen? Mareks is just one possible cause of blindness. Others are pecking or injuries, infections, ammonia odors, cataracts, vitamin deficiencies, and 2 viruses that I know of.
If she has Mareks, then all of your flock has been exposed, and it is in your environment from the chicken dander and dust everywhere. Are you planning on brooding the new chicks inside your house? You can buy a shipped vaccine and then keep the other chicks isolated for 2-3 weeks until they develop full immunity to the Mareks virus. But since the vaccine is not 100% effective, some could still develop symptoms. In any flock with Mareks, all chickens, vaccinated or not, will become carriers in the future.

I would post the pictures, then do some reading about the disease. I also would not get too concerned just yet. The best method for testing is still getting a necropsy performed after death, and the state vet can then do a Mareks test on tissue or feather shafts.

There is no need to euthanize this bird yet unless you want to get a necropsy. I would however, place her in a familiar environment with food and water closeby, to make sure that she is eating.

 

[Eggcessive]

Here are some additional links with pictures and a picture of ocular Mareks:
http://www.thepoultrysite.com/publi...usinduced-neoplastic-diseases-mareks-disease/

https://ucanr.edu/sites/poultry/files/246963.pdf

Mareks in right picture

 

[rdetraz]

Hi, welcome to BYC!

Sorry your gal is having trouble.

If you decide to cull or she passes... getting a necropsy is the only way to confirm or debunk Marek's.

Best info I have seen on the subject...
https://www.backyardchickens.com/articles/the-great-big-giant-mareks-disease-faq.66077/

Links to help if you decide to get a necropsy which is often affordable or free to back yard keepers...
https://www.backyardchickens.com/threads/how-to-send-a-bird-for-a-necropsy-pictures.799747/

https://www.aphis.usda.gov/animal_health/nahln/downloads/all_nahln_lab_list.pdf

Theses are links for the US. Adding your general location to your profile can help others to make the most relevant suggestions possible at a glance without having to ask first.

How old is your gal?

I personally do cull for suspected Marek's. While others may have been exposed already... an actively ill bird is actively shedding more virus among my flock. Less exposure is still less to me. In addition to that I feel as though all illness and disease attack the weakest link first and so I consider them a vector to other possible issues. There are some peeps on here who DO support and keep their Marek's birds alive. It's a personal choice. Consider if the bird is still having a good quality of life and also how it effect YOUR quality of life. Do you have the time or energy or desire to care for a special needs bird?

Please note, Marek's vaccinated birds NOT welcome here... to essentially hide AND spread the disease of they do catch it. The vaccine does NOT stop them from getting MDV but only lessens the symptoms. That makes it a deal breaker for me.

Some people who KNOW they have Marek's at their place and cannot afford (emotionally or otherwise) any loss of life should get vaccinated birds. There has been one gene identified that does provide resistance to MDV... I choose to breed for resistance which is not an option for everyone.

I know the first encounter with Marek's is scary! But it doesn't have to be as bad as people make it out. Hang in there!

The key to me with your new chicks and existing flock... nutrition, not over crowding, internal and external parasite control.

My girl was about 40 weeks when the blindness started, and it has been a couple weeks now that she is blind. I just don't know if I should cull her since (1) I'm assuming everyone else is already exposed and (2) she eats, drinks, walks, and roosts normally. She does get distressed when free ranging since she can't see the rest of the flock to keep up with them, but they return eventually. Presumably she should live the rest of her life fine? I'm much more worried about these babies coming in, but I guess at this point there isn't anything I can do to save them/reduce the risk of infection? I don't have a set up to permanently keep the unvaccinated birds apart from the vaccinated ones.

 

[rdetraz]

Welcome to BYC. Could you post pictures of the eyes of the hen? Mareks is just one possible cause of blindness. Others are pecking or injuries, infections, ammonia odors, cataracts, vitamin deficiencies, and 2 viruses that I know of.
If she has Mareks, then all of your flock has been exposed, and it is in your environment from the chicken dander and dust everywhere. Are you planning on brooding the new chicks inside your house? You can buy a shipped vaccine and then keep the other chicks isolated for 2-3 weeks until they develop full immunity to the Mareks virus. But since the vaccine is not 100% effective, some could still develop symptoms. In any flock with Mareks, all chickens, vaccinated or not, will become carriers in the future.

I would post the pictures, then do some reading about the disease. I also would not get too concerned just yet. The best method for testing is still getting a necropsy performed after death, and the state vet can then do a Mareks test on tissue or feather shafts.

There is no need to euthanize this bird yet unless you want to get a necropsy. I would however, place her in a familiar environment with food and water closeby, to make sure that she is eating.

Here are some pics: only symptom is the blindness

 

[Eggcessive]

I probably would be suspicious of ocular Mareks as well. Avian encephalomyelitis or AE as a baby chick can also cause some of the eye symptoms. Many BYC members deal with Mareks in their flocks every day. Some chickens tend to have immunity to the disease.

There is a blood test for Mareks that you may be able to get a local vet to draw and send away to a poultry lab. They also can do testing on a feather shaft at certain labs. The problem is that these tests can have a greater chance of false negatives which could give you a false sense of security.

Though it would be sad, you could also sacrifice and put the chicken down and send her to your state poultry vet for testing. A chicken with Mareks will shed dander and possibly contaminate more chickens. @casportpony and @rebrascora both deal with Mareks, and can give advice.

 

[rebrascora]

I'm afraid I haven't had a single case of ocular Marek's so far, so I'm not really sure there is a lot I can contribute.
Whilst I am also not in favour of the vaccine, in the OP's situation with hatchery chicks arriving, vaccinating them him/herself and practicing strict biosecurity measures for the first 3 weeks might be the best option. In my opinion, hatchery chicks that are unnaturally brooded have weaker immune systems than broody reared chicks and are more at risk of Marek's because of that and integration stress etc when the time comes. They are exposed to the highest level of the virus right at the point that they are under stress ie during integration into the flock, whereas broody reared chicks reared in the flock are exposed from day one and perhaps their immune systems have a chance to develop some resistance (a bit like coccidiosis) but don't have the stress to weaken their response and perhaps trigger it.