Marek's Disease

Marek's disease is a highly contagious disease in chickens causing tumor growth mainly in the abdomen area.

What is Marek's Disease?

Marek’s disease is a highly contagious disease in poultry that causes abnormal tissue or tumor growth mainly in the abdomen area, its also known as a Herpes virus in chickens. The extensive tissue growth can cause paralysis and nerve damage. There are five different syndromes that a chicken can get after being infected with the disease. It’s important to remember that these signs wont show up immediately upon contracting the disease, these syndromes take time to develop.

 

Know the Signs

Classic Marek’s Disease (neurolymphomatosis): causes paralysis of limbs and can cause difficulty breathing or dilation of the crop.  Also causes lesions in the nerves, there are frequently tumors in the skin, skeletal muscle, visceral organs. Organs that are commonly affected include the ovary, spleen, liver, kidneys, lungs, heart, proventriculus and adrenals.

Acute Marek’s disease: is an epidemic in a previously uninfected or unvaccinated flock, causing depression, paralysis, and death in a large number of birds (up to 80%). The age of onset is much earlier than the classic form; birds are four to eight weeks old when affected. Infiltration into multiple organs/tissue is also present.

Ocular lymphomatosis: causes the iris of the eye to turn grey also can show unequal size of the pupils, and blindness.

Cutaneous Marek’s disease: this can cause round, firm lesions at the feather follicles.

Immunosuppression: Causes suppression of immune system making the bird or flock more susceptible to contracting other diseases like coccidiosis and E. Coli.

How Marek's Spreads

Marek’s disease is mainly contracted through the respiratory system when dander from other infected poultry is inhaled. The disease can live extensive periods of time when it is not frozen and then thawed. The disease is resistent to some disinfectants (quarterary ammonium and phenol).

Prevention

There is no known cure for Marek’s disease once a bird or flock has been infected. There is a vaccination that most hatcheries offer to give your chickens that is very effective in preventing Marek’s disease. Marek’s disease cannot be cured with medicated feed.