Marek's Disease

Replies to This Discussion

Permalink Reply by Mojtaba Yegani on February 16, 2010 at 8:35pm

Hi Ratri,

I am not aware if there is any relationship between the occurrence of MD and bird strain.

Vaccination against MD is an effective strategy, but it does not necessarily mean that your flock will be 100% protected against the disease.

Like any other type of vaccine, there are many factors which can cause "failure" in achieving desired results from vaccination against MD.

Occurrence of MD in successive flocks in a farm definitely needs investigation about not only vaccination but biosecurity measures as well. How is your cleaning and disinfection programs between flocks?

Vaccination is part of a disease prevention program in poultry farms.

I'd suggest that you post this question on "Poultry Production" group on this website. It may help to get more responses from members.

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Permalink Reply by Ratriastuti Purnawasita on March 1, 2010 at 12:39am

Dear Mr. Yagani,

Thanks a lot for your respons. I agree, that vaccination can not guarantee 100 % that birds be free from exposure. And many factor influence the succesful of vaccination, especially in MD vaccination. And biosecurity is very important for minimalizing the case. In relation with strain I have read that some strain is more susceptible with MD, but I don't know which is the strain....

I shall try to share it in Poultry Production Group. Thanks for your suggestion.

Regards, Ratri

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Permalink Reply by Dr Gyula Nagy on March 2, 2010 at 3:13am

Mr Ratri!
In my experiences revactination of layers is not necessary. You have to vaccinate your birds as day olds individually by chickenherpes virus and cell-bounded vaccine likle Rispens simultaneously just after their hatching i.m. Forming out of protection will start just after the vaccination, but completion of it needs some days. Therefore You should concentrate the proper way of vaccination, storage and dissolving the vaccine the full dose of vaccine, and for high level of biosecurity of the farm/hous where the flock is intended to settle.
Best regards. Dr. Nagy, Hungary

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Permalink Reply by Ratriastuti Purnawasita on March 5, 2010 at 4:46am

Dear Dr. Nagy,

Vaccination done on 0 day. When the case still in growing periode, are revaccination is needed (the challenge is high?

Best regards, Ratri

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Permalink Reply by Dr Gyula Nagy on March 5, 2010 at 8:52am

Dear Sir!
Marek vaccine is administered only once on the day, as it was mentioned by You. This is correct.
After the vaccination a race against the time starts betveen the vaccine viruses and the wild viruses existing in the environment of the poultry (in the house) as fas as development of protection is concerned. This is the reason that the vaccination has to be performed as early as the day 0, in any case before the settling of the birds. The longer is this gap or the less wild viruses can be found in the house ( effectively cleaned and disinfected ) the better results can be expected with Marek s. If the protection started to develope and the premise is practically free of viruses,, the residual pathogens has less and less importance and possibility to cause a seriouse disease. A second vaccination for example in th 3rd-4th week has no meaning, because the vaccination must develope an effective protection by this age which can not improved by a second immunization. If not the second vaccination can not influence the pathological process caused by the wild Marek infection in the house (from infected environment). Therefore 1 vaccination on the 0 day must be effective.
Best regards: Dr. Nagy Gyula
some other conditions must be realized: correct biosecurity program, all in all out, personal hygiene, no backyard poultry, proper dissolving, treatment of vaccine, full dose of vaccine, proper way of vaccination is the hatchery . Take care the disinfection of lorris used for chicken transport.
If Marek disease is treated properly, Results will be significantly better.

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Permalink Reply by Dr. Balasubramaniam on March 2, 2010 at 5:10am

It is the case of vvMD Mr. Ratriastuti!. Developing strain resistant to MD is quite possible but none has developed one yet.

I presume you are not following all in all out system, In that case you vaccinate the chicks with cell associated Rispen and HVT strains (5000 pfu) s/c on 0 day of age and rear chicks in MD free environment for atleast 3 weeks.

Revaccination will not serve any purpose.

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Permalink Reply by ping wei on March 5, 2010 at 3:08am

Some questions need to be asked before the answer:
1. how can you know it is a case of MD, do you have the lab. diagnosis?
2. can you give more description of the case in details e.g. signs, lesions, mortality...

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Permalink Reply by Ratriastuti Purnawasita on March 7, 2010 at 8:47pm

Dear Mr. Wei,
The case is not mine but my colleagues's.
1. From history, physically, post mortum examination birds suspected from MD. And diagnose is taken from lab examination (histopathology).
2. The signs are birds have emaciated, lethargy. In post mortum exam found tumor in many organ. Mortality is high starting at 6 wks, about 30 %. In other farm starting at 16 wks and culling birds about 10 %.

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Permalink Reply by Ratriastuti Purnawasita on March 7, 2010 at 8:23pm

Dear Dr. Nagy,

Thank you very much for your sharing. One question, did MD case influence by bird strain? (perhaps a certain strain more susceptible than other ?

Regards, Ratri

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Permalink Reply by Dr.M.Saravanan on March 27, 2010 at 12:14am

In my point of view,there is no strain relation. Vaccination at day old that too in hatchery and rearing first 4 wks in Highly biosecured and isolated area will avoid MD! No means in booster vaccination at farm

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Permalink Reply by ping wei on March 27, 2010 at 4:25am

it seems to me that the flocks were in severely outbreak of MD (if the lab diagnosis is correct, but I still recomment to run a differentiated diagnosis with other tumour diseases such as AL and RE, because in my experience the coinfection of these tumour viruses is common and that always makes the disease more severe). There are two main reasons for that: one is the failure of vaccination, both the vaccine quality and the handling of vaccination may have problem; the other is the early infection of virulent MDV contaminated in the environment especially in the of multiple-age flocks. And the coinfections with other immunosuppressive diseases like CIAV, ALV, REV, e.g. may sure enhance the severity of MD.
Thanks for sharing.
Dr. Ping Wei.

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