Questions about Marek's

[LTygress]

Still dealing with this one hen with a bad leg/foot. It is SEVERELY swollen right now, so I'm not surprised that she won't walk on it.

But when she tries to walk, she acts like she can't quite feel that foot. She hobbles, and puts it almost too far in front of her. If she hits something like a fold in the blanket on my bed, she won't pick it up any further, and that is usually when she trips and tumbles over.

That would technically be a sign of paralysis. So I would think Marek's.

But there are some things still making me think otherwise. First, she's the offspring of two of my other chickens. And ALL adult chickens were vaccinated. Their offspring (the ones that stayed with me) were not (the ones I sold were vaccinated). Any NEW chicks or chickens coming in to my flock, get vaccinated.

But I haven't gotten any new chicks or chickens, aside from hatching my own eggs from my own flock, since May. This girl hatched in April, and is now 7 months old.

If she was going to develop Marek's, wouldn't she have become infected before now? Wouldn't she have become paralyzed or show some type of other symptom long before now?

Or is it possible to hold the virus for 7 months, and THEN become infected?

 

[BantamLover21]

How long ago did she start showing symptoms? The appearance of paralysis may be because her foot is so swollen that she can't feel properly, or it could just be temporary. About a month ago, I had a cockerel that (I think) injured his leg. One foot was paralyzed for 3 days, but eventually became normal again given rest. He still hasn't recovered from the injury, but at least he isn't paralyzed any more. If your hen's foot was badly sprained or crushed, that would probably account for its swelling and lack of feeling.

Or, it could still be Marek's. Simply having parents that are vaccinated does not mean that the offspring are going to be immune (the parents do pass on a small bit of resistance, though). And since Marek's disease is everywhere, even though you haven't introduced any new birds lately, she could have become infected by the environment. Many birds do show symptoms of Marek's when they are younger (around 4 weeks), but they can become infected (usually) until they are about a year old. By that point, they have almost always already been exposed to the Marek's virus, and will have shown symptoms by now if they were no resistant.

 

[LTygress]

Just a few days ago. She has been 100% fine until early this week. Never any problems before that.

 

[realsis]

You don't have to introduce new birds to get infected by Mareks. Above post is right. And having vaccinated parents won't help with the virus at all. In fact even vaccinated birds can get the virus.i believe its 10% of vaccinated birds still get mareks although vaccinated. Mareks is litterly every where and right now our only defence is the vsccination which is not 100% effective. Its sad but true that mareks can travel miles in the wind.our only hope is to vaccinste as babies and give time for immunity to develop before the babies are let outside. I read immunity can take 14 days some say even longer for the bodies to produce antibodies after vaccination. So basically after vaccination they should be kept inside for at least another month. I hope this information is helpful and I wish you the best.

 

[LTygress]

I'm pretty aware of all of that. My question is, wouldn't this particular hen develop symptoms of the disease long before now?

I can't guess by looking at my other chickens, because most of them HAVE been vaccinated. So chances are, they do have the virus, and won't ever show signs of an illness.

But this one having NO vaccine, should have been sick long before now, right? I should have seen at least one symptom MONTHS AGO, right?

 

[BantamLover21]

I'm pretty aware of all of that. My question is, wouldn't this particular hen develop symptoms of the disease long before now?

I can't guess by looking at my other chickens, because most of them HAVE been vaccinated. So chances are, they do have the virus, and won't ever show signs of an illness.

But this one having NO vaccine, should have been sick long before now, right? I should have seen at least one symptom MONTHS AGO, right?

Not necessarily. She may not have been exposed to the virus until now, or at least not enough of the virus to become completely infected. Or she may have been carrying it for months, but only recently have begun showing it due to stress of some sort.

 

[Wyandottes7]

I'm pretty aware of all of that. My question is, wouldn't this particular hen develop symptoms of the disease long before now?

I can't guess by looking at my other chickens, because most of them HAVE been vaccinated. So chances are, they do have the virus, and won't ever show signs of an illness.

But this one having NO vaccine, should have been sick long before now, right? I should have seen at least one symptom MONTHS AGO, right?

If the Marek's is in your area, a bird can really get infected at any time. Seven months old is a common age for birds to get Mareks, with 6-10 months being the usual age. If one of your other birds is the carrier of Mareks, it may not be shedding the disease all the time in the feather dander. Just because a bird has Marek's doesn't mean that it is contagious all the time (from what I've read). So, if one of your chickens only recently started shedding the disease, it makes sense that your bird is only now getting it.

 

[realsis]

From what I understand they ARE contagious at all times but might not be symptomatic like a silent carrier. No its not unusual for her age. She could have carried the disease and just now became symptomatic. Also Mareks is every where not just a paticular area and we are ALL at risk for this virus.

 

[Lady of McCamley]

I agree it's not unusual for her to show symptoms now if it were Marek's. It's very common to rear its ugly head just at point of lay (so 4 to 6 months of age). She could have been infected long ago, stressed by coming into lay (or some other stressor), and showing the effects of the lesions now.

Also, vaccination does not mean a bird doesn't get Marek's. They still get it. All the vaccine does is prevent the tumors from growing to the size that they produce negative symptoms, so you have asymptomatic but infected birds either from vaccination or from natural immunity, meaning they carry the virus but their body is keeping the lesions in check so no symptoms are noticed. (EDITED TO ADD: How often the virus is shed, I've forgotten...I got the feeling that it was shed all the time but the other poster may be correct that it is only at times of stress.)

The only reason for vaccinating at day old is it usually takes 2 weeks for the lesions to grow. Vaccinating the day old chick is the only way to get the vaccine in at a time they are not going to have lesions already present since Marek's does not pass from the mother to egg. You can vaccinate for Marek's later, but there is no guarantee the bird has not already been infected and harmful lesions are already started. (The research I've read is split on whether it is worth vaccinating older birds...some say yes, other's assume no I think with the presumption that lesions are already started and the vaccination won't have effect on those already begun.)

But then again...it might just be the sore foot causing swelling on a nerve. Here's hoping for you.

Lady of McCamley

 

[LTygress]

 If the Marek's is in your area, a bird can really get infected at any time. Seven months old is a common age for birds to get Mareks, with 6-10 months being the usual age.

Thanks. That is pretty much exactly what I was looking for. Everything else I have read says 12-16 weeks (four months) is when they develop it, but the web goes back and forth on the display of symptoms, because it mostly focuses on vaccinations, not the disease itself.

If it's in my area, I can pretty much guarantee she acquired it at or shortly after hatching. I've never had it in my flock before, but I am sure SOMEONE in this area has. It's VERY unlikely that this area is free of the virus - its the country. I've seen bags of chicken feed (a brand I don't buy) blowing down the street, so I am almost certain Marek's virus has already done the same.

I just needed to know about the speed of disease progression to know how likely it is that this foot problem is Marek's