Figure 4. Transmission electron micrographs of iridovirus cultured from the liver of a naturally diseased common frog (Rana temporaria) by using a fathead minnow epithelial cell line. 4a. Virus-infected cell. Large isocahedral viruses are conspicuous within the cytoplasm (arrows). Bar = 2 µm. 4b. Paracrystalline array of iridovirus. Bar = 200 µm.