A new iridovirus isolated from soft-shelled turtle.

A virus was isolated from soft-shelled turtle (Trionyx sinensis) with 'red neck disease' on a farm in Shenzhen, China, the virus multiplied and caused a cytopathogenic effect (CPE) at 15-30 degrees C in CO, FHM, CK and BF-2 cells. The optimum conditions for replication was in CO cells at 25-30 degrees C. The virus was sensitive to chloroform treatment, acid (pH 3) or alkaline (pH 10) conditions and heating at 56 degrees C for 30 min. Treatment with 5-iodo-2-deoxyuridine (IUDR) inhibited viral replication, indicating the presence of a DNA genome. Electron microscopy of infected CO culture fluid revealed spherical particles measuring 120-160 nm in diameter. Observation of ultra-thin sections showed numerous hexagonal viral particles in the cytoplasm and nucleus of cells typical of an iridovirus. This virus was moderately virulent for turtles in infection tests. We suggest that this virus is named soft-shelled turtle iridovirus (STIV).