Mareck's disease

[aeb1960]

Last month we lost a chick to Mareck's disease. Saturday, another, at about 14 weeks of age, had stiffness in its foot. We feared a repeat of what we had gone through with the other chick, so brought her in the house to separate her. She is not improving, but becoming more paralyzed in that whole leg.

My question is...how long does it take for symptoms to show in other chicks? This occurrence was a whole month after the first! How long will I have to wait before I incorporate these pullets in with the existing flock? I was going to wait till spring, but that is really only 6-10 weeks away!

Has anyone had this happen, where there was a month interval between cases of Mareck's. Thank you.

 

[aeb1960]

By the way, we have destroyed the chick which was obviously affected. I just don't know what to think about the other 7 that are left. They are all about the same age (one is a couple of weeks younger). We got them from the feed store at he end of November, at about 7 weeks of age. I guess that brings them to about 15 weeks of age. At the feed store, they told us that they never get vaccinated chicks, and don't have any problems. I won't believe that line anymore!

 

[myfinefeatheredfriends]

I've had a long history with Marek's Disease unfortunately ever since I bought unvaccinated hatchery Cochin chicks. Half of my flock died from it so I figured the other half would be carriers and had them put down. It just popped up again in my flock when a white Leghorn I bought came down with it 7 days before her second birthday. For my Cochins, I lost birds between the ages of 4 months to 2 years old. I no longer hatch chickens because of it. I bought the vaccine before but it is expensive. Now however I never buy chicks from hatcheries without vaccinating them for Marek's. Just too risky and too much suffering they go through. I believe all chickens can get it, some are just more susceptible than others. So sorry to hear you're going through this.

 

[myfinefeatheredfriends]

As for symptoms the birds start by acting like they're getting arthritis, usually become lethargic and hold their feet up. Then one of two things can happen: they either bounce back or become paralyzed. If they bounce back, they are still carriers and will eventually die. If they become paralyzed, they will die usually within 24 hours from not eating or drinking, though it could take as long as 3 days. I lost some of my favorite chickens to this disease.

 

[aeb1960]

Thanks so much for your input. I realize I spelled the disease name wrong. I am trying to understand about the need to put the other chicks down. It seems I have read about others who had chickens which, although, exposed, did NOT get Marek's. I wonder if it is from going back and forth from the established flock (all given to us by a neighbor, to get us started) to the chicks. I wish I had done more research before getting the chicks. At the feed store I was told that they would develop their own immuities so they did not get them vaccinated. Perhaps it is my fault for traveling from the older chickens to the new ones. None of the older chickens has been sick since we got them in October. Do I REALLY have to kill my 7 remaining chicks? Does being a carrier mean I would have to keep them away from the older chickens for as long as the younger pullets live? Does it mean I could never bring in new chicks, VACCINATED this time, to incorporate to the flock?

 

[hdowden]

Marek's disease is a Herpes virus infection of chickens, and rarely turkeys in close association with chickens, seen worldwide. From the 1980s and 1990s highly virulent strains have become a problem in North America and Europe.

The disease has various manifestations: a) Neurological - Acute infiltration of the CNS and nerves resulting in 'floppy broiler syndrome' and transient paralysis, as well as more long-standing paralysis of legs or wings and eye lesions; b) Visceral - Tumours in heart, ovary, tests, muscles, lungs; c) Cutaneous - Tumours of feather follicles.

Morbidity is 10-50% and mortality up to 100%. Mortality in an affected flock typically continues at a moderate or high rate for quite a few weeks. In 'late' Marek's the mortality can extend to 40 weeks of age. Affected birds are more susceptible to other diseases, both parasitic and bacterial.

The route of infection is usually respiratory and the disease is highly contagious being spread by infective feather-follicle dander, fomites, etc. Infected birds remain viraemic for life. Vertical transmission is not considered to be important.

The virus survives at ambient temperature for a long time (65 weeks) when cell associated and is resistant to some disinfectants (quaternary ammonium and phenol). It is inactivated rapidly when frozen and thawed.

your other birds are probably already infected with it....

 

[aeb1960]

Thanks for your detailed reply! I am interested in the freeze/thaw effect on the virus. Our winter has been up and down. For now, we are continuing to house the 6 (out of 10) remaining pullets separate from the established flock. However, they are on the same property, and if the virus is carried by the wind....there is no real isolation. My son is convinced that the chicks (which came unvaccinated from the feed store) contracted the disease from the other chickens, since two of our children had decided, quite early on, to "introduce" two of their pets to the chicks. Therefore, he concludes, we can go ahead and incorporate them into the established flock of 17. I am leary...that would mean definitely contaminating the rest of the yard and the large chicken coop. Another idea my son had would be to bring one of the older chickens which is soon due to be culled because of her age, and put her with the Marek's-exposed pullets to see what would happen to her. If no symptoms...put them at the back with the others. My fear is the delay which can occur before symptoms are visible. Any suggestions? Thanks again!