Marek's disease is a highly contagious disease of poultry caused by a herpes virus. The virus invades white blood cells and is shed in skin cells and dander. The disease is transmitted readily among chickens through direct contact with infected birds or through inhalation of contaminated dust. Although some birds can live with the infection, the mortality rate is high. There are four forms of the disease based on location of lesions: cutaneous (skin), neural (nerves), ocular (eye) and visceral (internal organs).
Endemic Areas
Marek's disease is found worldwide.
Clinical Signs
Signs of the illness can include any of the following:
- Depression
- Paralysis of leg(s) or wing(s)
- Twisted neck
- Discolored or irregularly shaped iris
- Weight loss
- Poor appetite
- Diarrhea
- Sudden death
- Enlarged nerves and tumors, particularly associated with nervous tissue and ovaries, evident at necropsy
Treatment
There is no specific treatment for Marek's disease. Any bird suspected of having Marek's disease should be reported to the State Veterinarians or USDA Area Veterinarian in Charge.
Prevention
A highly effective vaccine is available for Marek's disease. Hatcheries offer the option of purchasing chicks vaccinatined for Marek's Disease. This disease can be prevented by implementing a sound vaccination program and following the USDA-APHIS Biosecurity for the Birds program.
Public Health
Marek's disease is not a public health threat.
Links
Marek's disease -Purdue University
