Not Mareks?!?!?!?! What could it have been?

[Leihamarie]

You bring up a good point though with verifying that the sample was good. I did everything in my power to collect a clean, viable sample, but maybe something went wrong in the transport or... who knows! I have more questions for the lab, LOL!!!!! At this point I just say, "Hi again, it's Leiha in San Diego with the chickens" and they know who it is, hahahahahaha!!!!

I really appreciate your input, especially as a former microbiologist!

 

[aligarysmom]

Ok sorry but being a testing lab technician I have some questions for clificiation. What samples did you send? Are these samples from the known Merecks birds. Ie the ones that died? Or are these from the birds they were vaccinated ?

 

[Leihamarie]

Ok sorry but being a testing lab technician I have some questions for clificiation. What samples did you send? Are these samples from the known Merecks birds. Ie the ones that died? Or are these from the birds they were vaccinated ?

No known Marek's birds still exist. The blood samples came from my current, vaccinated flock. Three of my current chickens had direct exposure to Mabel (the last known Marek's bird who died in Feb 2017). The other four of my flock had no direct exposure to known Marek's birds, but did have direct exposure to the environment where the known Marek's birds lived/ dust-bathed, foraged, etc... I only have about a 700sf yard, so, it would be COMPLETELY saturated in Marek's Disease Virus if it were present.

 

[aligarysmom]

So why would anyone think or tell you that the viral load on these vaccinated chickens would be positive?

The viral loan measures the active viral rate for infected birds. Let me give you an example. You get hep c. The first test done is for antibodies to the antigen for the virus. The antibody titer will
Always be elevated. The point of vaccination is to have antibodies to immediately recognize the virus and kill it before it can infect the cells and replicate. Replication is the viral load. If you have immunized birds that actually have an effective immune system they will never have a viral load. Always negative. If the immune system had a proper response that’s the point of the vaccine.

 

[April’s Zoo]

Am I missing something? Isn’t the idea of the vaccine to prevent the new birds from getting Marek’s?

I wouldn’t expect the vaccinated birds to test positive by DNA or any other testing.... kinda like after I get a flu vaccine, if my doctor later tests me for influenza it shouldn’t come back positive, even if I’ve been living in the same house with a whole bunch of people shedding virus all over the place. (Not a perfect example, because while the flu vaccine covers many of the flu viruses, it doesn’t protect against all strains— but you get the idea).

If they’re just testing for antibodies— which would be present after vaccination— why would that require a DNA-based test?

Lol— aligarysmom and I posted at the same time... and said pretty much the same thing... great minds think alike, I guess.

 

[Leihamarie]

So why would anyone think or tell you that the viral load on these vaccinated chickens would be positive?

The viral loan measures the active viral rate for infected birds. Let me give you an example. You get hep c. The first test done is for antibodies to the antigen for the virus. The antibody titer will
Always be elevated. The point of vaccination is to have antibodies the immediately recognize the virus and kill it before it can infect the cells and replicate. Replication is the viral load. If you have immunized birds that actually have an effective immune system they will never have a viral load. Always negative. If the immune system had a proper response that’s the point of the vaccine.

The Marek's vaccine is leaky. It prevents symptoms and death but it doesn't prevent the chicken from contracting and spreading the virus. Regular PCR analysis (from my understanding) can show whether or not Marek's Disease Virus is present, but not how virulent it is. There are different virulence levels ranging from virulent to very, very virulent. The real-time quantitative PCR analysis can differentiate between strains and also determine the virulence level.

 

[aligarysmom]

I have to say that doesn’t make sense. So it keeps the viral load low enough not to have symptoms? If the immune system recognizes the virus and stops it from entering cells it would otherwise infect you should never have a viral load. Let me look into this and get back to you, because a vaccine should either be effective or not. There isn’t really a middle ground. And your test results kinda indicate what i would expect to see from a vaccinated animal against a given virus.

 

[Leihamarie]

Am I missing something? Isn’t the idea of the vaccine to prevent the new birds from getting Marek’s?

I wouldn’t expect the vaccinated birds to test positive by DNA or any other testing.... kinda like after I get a flu vaccine, if my doctor later tests me for influenza it shouldn’t come back positive, even if I’ve been living in the same house with a whole bunch of people shedding virus all over the place. (Not a perfect example, because while the flu vaccine covers many of the flu viruses, it doesn’t protect against all strains— but you get the idea).

If they’re just testing for antibodies— which would be present after vaccination— why would that require a DNA-based test?

Lol— aligarysmom and I posted at the same time... and said pretty much the same thing... great minds think alike, I guess.

@april's zoo- Marek's vaccine isn't like the flu vaccine. Vaccinating chickens for Marek's Disease will prevent them from dying from the virus if they have enough time to build resistance to it between vaccination and exposure.

 

[Leihamarie]

I have to say that doesn’t make sense. So it keeps the viral load low enough not to have symptoms? If the immune system recognizes the virus and stops it from entering cells it would otherwise infect you should never have a viral load. Let me look into this and get back to you, because a vaccine should either be effective or not. There isn’t really a middle ground. And your test results kinda indicate what i would expect to see from a vaccinated animal against a given virus.

the vaccine doesn't prevent infection, so my vaccinated birds will still be infected with Marek's if it's present (which it should be), giving a positive result. That's what's confusing. Here's some more info on how Marek's vaccine prevents death, but doesn't prevent infetion: http://www.caes.ucdavis.edu/news/articles/2016/11/how-vaccines-ward-off-chicken-disease

 

[sawilliams]

Read through the comments not the attachments. One thing I recall readinv (and forgive me if I'm wrong) the vaccine doesn't prevent the virus from spreading but not all exposed birds will become carries either. So my thought is maybe there's a chance you just got lucky and the 3 direct contact birds simple avoided becoming carries. And the virus simply didn't have a chance to spread to the newer chicks. Heck not even the flu vaccine is perfect but sometimes we get lucky right