Isolation and Some Characteristics of an Agent Inducing Anemia in Chicks

SUMMARY A transmissible agent inducing anemia in chicks (chicken anemia agent; CAA) was isolated in specific-pathogen-free chicks from chickens in the field. Chicks were inoculated intramuscularly with CAA (about 1040 CID5o/chick) at 1 day old. By 14 days postinoculation they had severe anemia, with a hematocrit value below 20%, a red-blood-cell count below 1,000,000/mm3, and a white-blood-cell count below 5,000/mm3. Morbidity was 100%, and mortality reached about 50% by 28 days postinoculation. Gross lesions found in the affected chicks were watery blood, yellow to white bone marrow, marked atrophy of the thymus and bursa of Fabricius, swelling and discoloration of the liver, and sometimes hemorrhage throughout the body. CAA was resistant to treatment with chloroform or ether, and to heating at 80 C for 15 minutes. It passed through a membrane filter of 25-nm pore size. It produced no cytopathic effect in chicken kidney cell cultures or had no fatal effect on embryonating chicken eggs. Specific antibody was produced in chickens inoculated with CAA. These findings suggest that CAA may be a new viruslike agent