Factors Involved in Mortality From Avian Lymphomatosis

LYMPHOMATOSIS is apparently a naturally occurring malignant disease of chickens characterized by the formation of lymphoid tumors which may be found in nearly all tissues of the bird’s body. Research makes it increasingly evident that this disease is communicable and may be transmitted under natural conditions, both through the egg and by contact (Waters and Prickett, 1944, and Waters, 1945a). It is equally evident that modifications of the environment (Hutt, et al., 1944) and genetic resistance (Hutt, et al., 1941; Taylor, et al, 1943; and Waters, 1945b), determine to a large extent the incidence of lymphomatosis which occurs in experimental groups of non-inoculated chickens when they are exposed to the disease. A knowledge of the part played by the pathogen or causative agent of lymphomatosis is not clearly defined. Inability to identify, characterize, and control such an agent is a definite handicap in studies involving natural transmission of this disease.