 Characteristics of avian pox include the formation of intracytoplasmic inclusion bodies ('Bollinger bodies') which are composed of mononuclear inflammatory cells and have been detected in the thymus, spleen, bone marrow, middle ear and air sac.Similar inclusion bodies which are associated with inflammation have also been seen in the epidermis, feather follicles, sinuses and oral mucosa lining.Apart from the symptoms mentioned above, more general signs of infection include weight loss, loss of feathers and scaly skin on the head, neck and back.