Marek’s Disease is a highly contagious viral (Alphaherpesvirinae) disease of poultry and can be found in both commercial and backyard birds. The virus is airborne and spreads through feather dander and feces. The virus is prevented by vaccinating birds while in the egg or shortly after hatching.

The clinical signs can present as early as 3-4 weeks old, but are more common between 12-30 weeks. Signs are dependent on the organ systems effect. The most common clinical signs include, but are not limited to paralysis (inability to use legs), drooping wings, uneven pupil size, enlarged feather follicles, labored breathing, decreased growth rate, and/or decreased egg production. Unfortunately, this disease is fatal in poultry. Final diagnosis of this disease is made via necropsy (an internal examination after death). It is important that if you suspect Marek’s disease in an individual or your flock that you have them evaluated by a veterinarian.

Vaccination is the key to prevention. Consider purchasing birds from hatcheries that vaccinate their chicks prior to shipping. If you are a backyard breeder its smart to vaccinate birds on the first day out of the egg. Vaccination is not effective in older birds.

Biosecurity measures are steps taken to help prevent introduction of harmful diseases. Important steps to help prevent Marek’s disease include limiting introduction of new birds (especially if vaccination status is unknown) to your flock, separating young birds from older birds, and disinfection of all materials, equipment, and people (shoes/clothes) that work on your farm/property. Our veterinary team can help you develop biosecurity protocols to help protect your flock.