Did you cull your chickens with Mareks?

[adladladl]

I’m not a pro by any means and still new to chickens. We had a bird test positive for Marek’s after she died (soon into our chicken owning btw) and I freaked out. Then I calmed down and any new chicks have been vaccinated. And they have been fine. I think a loss here and there with the chicks but not more than seems to be average. Anyway, sorry you’re dealing with this. Initially I thought it was the end of the world (and my chicken keeping) but many MANY local chicken folks calmed my fears and assured me that Marek’s is not the end of the world if dealt with properly and was more commonly than I realized. We eat their eggs

Do they lay normally or at a reduced level? So you kept the parent birds and that ended ok? I am thinking about keeping these 100 birds and breeding their babies and vaccinating at birth and keeping them away from the adults. That way, I don't have to cull 100 birds but I don't want to mess up.

 

[adladladl]

Marek's Disease Control

• Genetic Resistance = best cure

• Stress Control = next best control measure
  
• Vaccination = may be needed in some flocks

There are no anti-viral medicines available to treat Marek's Disease so we must look to understanding the nature of the disease itself in order to develop a cure.



The first step to managing this disease is to identify whether the virus is present in your family of birds as some families are resistant to the disease - as the best way to prevent Marek's Disease is to develop a family of birds that is naturally resistant against the virus. Acquire families of birds and use sires that are resistant to MD, because there is strong level of heritability for genetic resistance against MD.

Alternatively, following an outbreak use strong male survivors as these birds have shown a resistance to MD. Developing a family of birds that is genetically resistant to Marek's Disease is by far the best way to cure the disease – but remember stress management measures are also a must!



Stress factors especially social stress is known to precipitate Marek's Disease. Social stress is any form of anxiety produced by overcrowding, poor sanitation, improper housing, other illnesses like worms, coccidiosis, lice and mites - or mixing older birds with young birds - that prevent the young birds from resting eating or drinking – basically preventing them for being happy. Stress management is the best way to control Marek's Disease in flocks that have previously experience Marek's diseases from time to time.

Genetic factors and age of initial exposure to the virus are important determinants of MD susceptibility. It causes most problems in pullet flocks under 16 weeks of age and cockerels are more resistant to Marek’s Disease. Symptoms of Marek’s Disease may also be seen in pullets near or soon afterthe onset of egg production at 5-6 months of age or older depending on breed of chicken.



Because there are no antiviral drugs to cure the disease there are two options open to you for preventing this disease – vaccination or to breed yourself a resistant family of chickens – whatever option you take good management practices must be followed to reduce stress, as ultimately Marek’s Disease is stress induced.

 

[adladladl]

https://www.birdhealth.com.au/mareks-disease

 

[adladladl]

Vaccination is good option for flocks or families who have experienced moderate to high levels of Marek's Disease (MD) – or even in flocks that experience poor health for reasons that remain unclear as often in these flocks Marek's disease is the underlying cause of the problems as the virus prevents the immune system from responding to disease challenges so that coccidiosis and E. coli infections as well as respiratory infections become more common and often there is a poor response of these diseases to treatment and they tend to recur.

Vaccination is given at one day of age because Marek’s Disease has a short incubation period of 2 weeks with signs of disease appearing in birds as young as 3 weeks of age – even though the disease is not spread through the egg and newborn chicks are protected by maternal antibodies for a few weeks.

The aim of vaccination is to prevent the virus from accumulating in the environment of the young chickens, as Marek's Disease is highly contagious being spread through dander form feather follicles (feather dust) and transmitted by inhalation.

Vaccination is the only means for controlling Marek's Disease in infected flocks because there are no treatments that cure an infected bird.

 

[adladladl]

The first step to managing this disease is to identify whether the virus is present in your family of birds as some families are resistant to the disease - as the best way to prevent Marek's Disease is to develop a family of birds that is naturally resistant against the virus. Acquire families of birds and use sires that are resistant to MD, because there is strong level of heritability for genetic resistance against MD.

Alternatively, following an outbreak use strong male survivors as these birds have shown a resistance to MD. Developing a family of birds that is genetically resistant to Marek's Disease is by far the best way to cure the disease – but remember stress management measures are also a must!....
This is the advice from this doctor above. Have anyone reading this actually kept your birds and bred them? Like I stated above, two died and zero of the rest of the 100 are showing symptoms.

 

[adladladl]

1. Don't vaccinate birds so that the survivors will become resistant. Genetic disease resistance takes decades to develop and so far, has not been successful with Marek's Disease. If it were successful, one would think the commercial chicken genetic companies would have developed resistant chickens by now.

 

[adladladl]

https://extension.psu.edu/mareks-disease-in-chickens

 

[adladladl]

Yet another state article basically says that I cannot breed to get genetic resistance

 

[adladladl]

Marek's disease is one of the most ubiquitous avian infections; it is identified in chicken flocks worldwide. Every flock, except for those maintained under strict pathogen-free conditions, is presumed to be infected.

Marek disease is a highly contagious viral disease of poultry characterized by T-cell lymphomas and peripheral nerve enlargement. Standard criteria used for diagnosis include history, clinical signs, gross necropsy, and histopathology. Although no treatment is available, current vaccines are highly protective.


Chickens are the most important natural host for Marek's disease virus (MDV), a highly cell-associated but readily transmitted alphaherpesvirus with lymphotropic properties of gammaherpesviruses. Quail can be naturally infected, and turkeys can be infected experimentally. However, severe clinical outbreaks of Marek's disease in commercial turkey flocks, with mortality from tumors reaching 40%–80% between 8 and 17 weeks of age, were reported in France, Israel, and Germany. In some of these cases, the affected turkey flocks were raised in proximity to broilers. Turkeys are also commonly infected with turkey herpesvirus (HVT), an avirulent strain related to Marek's disease virus that is commonly used as a Marek's disease vaccine in chickens. Other birds and mammals appear to be refractory to the disease or infection.

Marek's disease is one of the most ubiquitous avian infections; it is identified in chicken flocks worldwide. Every flock, except for those maintained under strict pathogen-free conditions, is presumed to be infected. Although clinical disease is not always apparent in infected flocks, a subclinical decrease in growth rate and egg production may be economically important.

Etiology of Marek Disease in Poultry​

Marek's disease virus is a member of the genus Mardivirus within the subfamily Alphaherpesvirinae. Within the genus Mardivirus are three closely related species previously designated as three serotypes of Marek's disease virus. Gallid alphaherpesvirus 2 (MDV serotype 1) represents all virulent Marek disease virus strains and is further divided into pathotypes, designated as mild (m), virulent (v), very virulent (vv), and very virulent plus (vv+). Gallid alphaherpesvirus 3 (MDV serotype 2) and Meleagrid alphaherpesvirus 1 (turkey herpesvirus, MDV serotype 3) represent avirulent virus strains isolated from chickens and turkeys, respectively, and are commonly used as vaccines against Marek's disease.

Transmission and Etiology of Marek Disease in Poultry​

Marek's disease is highly contagious and readily transmitted among chickens. The virus matures into a fully infective, enveloped form in the epithelium of the feather follicle, from which it is released into the environment. It may survive for months in poultry house litter or dust. Dust or dander from infected chickens is particularly effective in transmission. Once the virus is introduced into a chicken flock, regardless of vaccination status, infection spreads quickly from bird to bird. Infected chickens continue to be carriers for long periods and act as sources of infectious virus. Shedding of infectious virus can be reduced, but not prevented, by prior vaccination. Unlike virulent strains of Marek's disease virus, which are highly contagious, turkey herpesvirus is not readily transmissible among chickens (although it is easily transmitted among turkeys, its natural host). Attenuated Marek's disease virus strains vary greatly in their transmissibility among chickens; the most highly attenuated are not transmitted. Marek's disease virus is not vertically transmitted.

• There is no effective treatment for Marek's disease
• Prevention methods include vaccination, biosecurity, and genetic resistance

Vaccination is the central strategy for the prevention and control of Marek's disease, along with strict sanitation to reduce or delay exposure and by breeding for genetic resistance.

https://www.merckvetmanual.com/poultry/neoplasms/marek-s-disease-in-poultry

This article basically says everyone could have it...another article said 30-50% of chicken owners have it.

 

[TwoCrows]

Lots of helpful information here @adladladl!