Isolation of chikungunya virus contaminating an Aedes albopictus cell line

An Aedes albopictus cell line was found contaminated with structures morphologically compatible with an alphavirus. Rapid isolation of a cytopathic virus was effected by combining sonication, concentration with Aquacide II-r, rate zonal sedimentation and subsequent plating of fractions on Vero cells under agar overlay. The virus caused neithedeath nor disease on inoculation into infant and adult mice. It produced a c.p.e. in Vero and BHK 21 cells, and multiplied in Singh's Aedes aegypti cells. The virus was identified serologically as chikungunya by complement-fixation and plaque reduction netralization test. Virus was not detected in a single attempt by these methods in the American Type Culture Collection A. albopicturs line. The presence of chikungunya virus in A. albopictus cells is not easily recognized and may complicate interpretation of experimental results.