Marek's Disease

 

What is Marek’s Disease?

One of the most common diseases in chickens is Marek’s Disease. As a type of herpes viral disease, Marek’s Disease cannot make people sick, but once a bird is infected, it’s infected for life. Depending on the strain of Marek’s and the breed of the bird, not all birds will show signs of sickness. Regardless, it’s important to understand that once you have infected birds, you’re at risk for losing a large portion of your flock.

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How Does Marek’s Disease Transmit?

Marek’s Disease is very easily transmitted through a flock. The dander from an infected bird only has to be inhaled by another bird for the strain to be transmitted. In fact, since infected birds are constantly shedding the virus, a chicken coop that contained the virus can be contaminated long after the birds are gone. Birds can even be contaminated through handlers’ shoes or clothing as they travel from coop to coop, so it’s important to know the signs your birds are infected before the virus can spread.

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It’s also important to note that Marek’s Disease cannot transmit vertically, meaning it cannot go from the mother hen through the egg to the chick. So if you get a new chick or chicken that has Marek’s, it’s not because the parent was infected, but it’s because the chick came into contact with Marek’s after it was hatched.

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What are the Symptoms and Signs?

Identifying the symptoms and signs of Marek’s Disease in infected birds can help save the health of a large majority of your flock. If caught early enough, it is likely most of your flock will remain uninfected. A few of the outward symptoms you may notice are:

• Paralysis, particularly in the legs, wings, and neck

• Tumors can appear in the feather follicles of your bird, but also internally on organs

• Irregular pupils, gray irises, or vision impairment

Some of the symptoms of Marek’s can be related to other diseases or health problems, so it’s important that you isolate any bird with these symptoms and seek veterinary advice.

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Can Marek’s Disease Be Cured?

Unfortunately, if your chicken contracts Marek’s Disease, there is no cure or treatment. If your chicken has come into contact with Marek’s Disease, you may have an infected bird on your hands without even knowing it. Chickens can contract this herpes virus without showing any symptoms, or even have a few symptoms that never fully progress.

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How Long Do Chickens Live with Marek’s Disease?

Depending on the age and health of your chicken, an infected bird can live a mostly normal life up until the disease progresses. Once tumors develop on vital organs or paralysis takes effect, your birds’ quality of life will be greatly reduced.

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How to Prevent Your Chickens from Catching Marek’s Disease

The best way to avoid any strains of Marek’s Disease infecting your flock is to stop it before it even starts. From day one, your chicks should be vaccinated against the disease and not be introduced to any new birds for at least a week while the vaccine takes effect. While the vaccine will prevent birds from experiencing symptoms and greatly diminish the spread of the disease, a Marek’s Disease vaccination cannot completely prevent infection.

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To further prevent the disease, you should also practice good biosecurity in your coops, ensuring you don’t carry any diseases between sick and healthy birds. This means keeping chicken areas clean, changing clothes when going to different chicken locations, controlling the rodent and pest population, and not immediately adding new chickens to your current flock.

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