How Can Marek's Disease Affect Chickens? 5 Questions, Answered

Key Takeaways

• Marek’s Disease is a highly contagious and often fatal viral disease affecting chickens and turkeys raised near chickens, spreading primarily through infected feather dander.
• The disease can present in neurological, visceral, or cutaneous forms, causing symptoms such as paralysis, vision impairment, weight loss, and skin changes around feather follicles.
• Mortality rates can range from moderate losses to complete flock loss, and infected birds are more vulnerable to secondary infections.
• There is no treatment for Marek’s Disease once birds are infected, making early prevention critical for flock health.
• Vaccinating healthy one-day-old chicks is the most effective way to protect flocks and reduce the risk of devastating losses.

Poultry producers and backyard farmers, beware. Marek’s Disease is all-too-common and quickly fatal. Could your chickens be at risk? Learn more in this FAQ, offering answers to five common questions about the disease.

What is Marek’s disease?

Marek’s Disease, also known as MD, is a herpes infection impacting chickens, as well as turkeys that are raised near chickens. This highly contagious disease has troubled producers and their flocks since the 1980’s, across the U.S. and Europe. Infection is usually spread through the respiratory system, caused by infective feather-follicle dander. The disease manifests itself in three ways, neurological, visceral and cutaneous, and it can be quickly detrimental to flocks. The key to disease prevention is through vaccination.

Is the disease fatal?

Unfortunately, yes. This disease can cause mortality rates from moderate levels up to 100%. Affected birds also can be more susceptible to other parasitic and bacterial diseases.

What are common symptoms?

There are many clinical signs of disease to keep watch for, including: weight loss, paralysis in legs, wings and neck, irregular pupil and grey iris, impaired vision, and roughened skin surrounding feather follicles.

Is there a treatment for disease?

There is no treatment for Marek’s Disease.

How can Marek’s Disease be prevented?

Vaccination is key for the prevention of this devastating disease. MD-Vac CFL is recommended for the vaccination of healthy one-day-old chicks to aid in the prevention of the signs and lesions of Marek’s disease. This vaccine can be best administered using the Automatic Ultra-Precision Syringe or ¾" disposable needles.

Whether for horse, livestock, or pet, Valley Vet Supply is your one-stop shop for trusted care. Explore more of our poultry category at ValleyVet.com