RETICULOENDOTHELIOSIS IN CAPTIVE GREATER AND ATTWATERS PRAIRIE CHICKENS

Reticuloendotheliosis in captive greater (Tympanuchus cupido pinnatus) and Attwater's (T. cupido attwateri) prairie chickens is reported for the first time. Between September 1993 and August 1994, two adult fem ale wild-caught greater prairie chickens housed at Texas A&M Universit y (College Station, Texas, USA) were observed with multiple subcutaneo us nodules. Both birds were euthanatized. Complete necropsy examinatio ns revealed lesions limited to the skin of each bird. Histopathologic examination of lesions revealed pleomorphic lymphoreticular cells sugg estive of reticuloendotheliosis and reticuloendotheliosis virus (REV) was demonstrated in tumor tissue by polymerase chain reaction and viru s isolation. Between September 1994 and June 1995, five additional gre ater prairie chickens and two Attwater's prairie chickens were euthana tized or found dead with evidence of lymphoreticular neoplasia in mult iple organ systems. Initial testing of the captive flock in December 1 994 for evidence of viremia and antibody to reticuloendotheliosis viru s revealed over 50% of the tested birds were viremic, but none develop ed antibodies. Subsequent testing between January 1995 and January 199 6 indicated that once infected with reticuloendotheliosis virus, Attwa ter's prairie chickens tended to remain outwardly healthy despite pers istent viremia compared to infected greater prairie chickens which had higher morbidity and mortality rates within 60 to 90 days after initi al detection of viremia and did not usually develop persistent viremia . Antibodies to REV were detected in only three captive greater prairi e chickens and only in 1995. Six of the nine birds that were euthanati zed or found dead due to reticuloendotheliosis developed viremia prior to death; three birds were not tested prior to death. Testing of free -ranging greater and Attwater's prairie chickens for reticuloendotheli osis is recommended prior to translocation or release.