Ministry of Higher Education and Scientific Research University of Al-Qadissiyia Collage of Veterinary Medicine Practical Poultry Diseases Forth Stage Marek’s Disease (MD) Assist. Lecturer Abbas Hadi Jasim Al-Mossawi

Marek’s Disease (MD) Etiology Herpes Virus

depression, weight loss, and diarrhea

Paresis

Paresis and paralysis are usually asymmetrical one leg forward and one leg backward

Leg paresis (partial paralysis)

irregular pupil

Lymphoid infiltration of the iris may interfere with normal pupil dilation and constriction.

A lymphoma lesion in the wall of the gizzard

Tumor in the kidney

Unilateral enlargement of sciatic nerve

Grey iris and irregular pupil

Ocular lesions, due to lymphoid infiltration of iris that causes white discoloration. The pupil is often irregular and does not respond to light

Enlarged of feather follicles

lymphoproliferative skin lesions

Swelling of the feather follicles

Tumors on the Liver

tumors in the liver

tumors in the spleen

Enlarged kidneys , firm on palpation, and may have white to grey areas of discoloration

Lymphomas in spleen, giving the organ a mottled white appearance

nodules on kidney and ovary lead to enlargement

tumors in the ovary

multiple lymphomatous lesions in the lungs.

Tumors in the heart

Tumor in the heart

A nodular lymphoma in the mucosa of the proventriculus

White lesions in the wall of the proventriculus

tumors in the intestines.

tumors have infiltrated the jejunum and surrounding mesentery

A large number of tumors in the pancreas

Unilateral enlargement of sciatic nerve

Unilateral enlargement of sciatic nerve