Vaccines for Marek's disease

Agree with Surindet

Dear Dr. Kashif, There are many causes of failure of MD Vaccination. Improper storage of cell associated vaccine in liquid nitrogen ( Tepm. -196 degree C) is one of them. No doubt MD is a horizontally transmitted disease, but because vaccination is always done in DOC in the hatchery, this is why the commercial farmers mostly concentrating on this part. The 2nd most important part is the proper cleaning & disinfection of rearing area required to get immunity from vaccine particularly during 1st 2 weeks. I & other writers has already explained this part in details. Dr. M. Akram, Ph.D.

Sir proper handling and inoculation required great attention

Marek disease vaccination should be brought into practice either in 18 th day to the embryos or else in the very first week after coming out of hatcheries and of course after pursuing all safety protocols prior vaccinating the flock. Commercialy the task is carried out through fine sprayer to enable fine droplets of live attenuated vaccines gain access through nostrils of chicks running on a conveyor. Any mis executions in above step may bring the task to be an abortive and that invite stress to precipitate infection in subsequent phases as highlighted now. It should be certain that the live attenuated virus should ensures it's process of attenuation or else same may act like a pathogen with full virulence only during application. Dr. R. P. Chakraborty

Mareks vaccine is never done by spray. All vaccines are to be administered by injection either 18thday or day one. Mareks vaccine works by blocking specific receptors. Better we vaccinate early and give lead to vaccine virus before the field virus ( in broader houses) races to the receptors

Sir very much important and valuable comment on vaccine. Please keep on delivering this type of facts of which many people are not aware of. Thank you so much

MD vaccination failures may occur due to several factors This will also an important fact in the failures of the response to the immune foreign gene inserts. using recombinant HVT vector vaccines

Two different vaccination proceedings “in Ovo” and day old s.c hatchery vaccination
Can draw a list of application problems,of coarse quality of vaccine (e.g PFU titer etc) May play a role

Hi ; Grzegorz Wozniakowski your question is why you dont find DNA of Rispens vaccine ; I have experience using many bivalent vaccine from different company vaccine making . in one experiment compared the replication ability of tow by testing the DNA in feather papilla in weeks 1-2-3 after vaccination after 1 week in one product only 30% was positive and another 100% . in 2 week 70 and 100 respectively . The reason for test was because of using new brand of vaccine saw Marek disease in pullet and after that . all of work in managing vaccine handling was as before the only difference was changing the brand of vaccine . I believe that seed and process that vaccine making technology in not similar and hence the quality of vaccine are not the same .and not founding DNA you mentioned be because of vaccine quality. As you know Marek virus is in every poultry houses and near 100% of commercial chicken even those that have no any mortality shed it in their life . and infection whit it ocurre in fist week of life , proper vaccination by good quality vaccine and good clean house is needed to prevent it .

My speculations are that birds may get exposed to the virus before protective immunity is developed especially following sc MDV inoculation at day one and less so with the inovo approach. The vvMDV in circulation in many places may not respect the present vaccines in use.