EXPERIMENTAL-INFECTION OF AUSTRALIAN ANURANS (LIMNODYNASTES-TERRAEREGINAE AND LITORIA-LATOPALMATA) WITH BOHLE IRIDOVIRUS

Challenge studies with Bohle iridovirus (BIV), a recently isolated Australian iridovirus, were performed with 2 Australian anurans. Juvenile Limnodynastes terraereginae and Litoria latopalmata were highly susceptible to BIV, while larval L. terraereginae were less susceptible. L. terraereginae and L. latopalmata juveniles injected intraperitoneally with 10(3) TCID50 (50% tissue culture infective dose) ml(-1) BIV died 6 to 10 d after injection. BIV could be transmitted by natural routes in L. terraereginae with mortality occurring from Day 14 to 26. Mortality occurred on Days 13 and 33 in L. terraereginae juveniles that were bath-challenged with BIV at a titre of 10(3) TCID50 ml(-1). BIV was retained for at least 40 d in the frogs. Larval L. terraereginae were bath-challenged at 10(0), 10(1), 10(2.5) and 10(4) TCID50 ml(-1) BIV. Low mortality occurred in the 10(2.5) and 10(4) TCID50 ml(-1) challenges, but BTV was isolated from one tadpole in the 10(1) TCID50 ml(-1) treatment sacrificed 16 d post challenge. Pathological changes were similar for larvae and juveniles of both species, and included renal, hepatic, splenic and pulmonary necroses, with pyknosis of erythrocytes also being observed. Immunoperoxidase staining techniques using cross-reactive anti-epizootic haematopoietic necrosis virus (EHNV) polyclonal antibody indicated the presence of BIV in the kidney, liver, lung and spleen of infected juveniles.