Inactivation of West Nile Virus during Serologic Testing and Transport

Inactivation of West Nile virus (WNV) in enzyme-linked immunosorbent assay (ELISA) wash buffer at 37°C was studied, as well as inactivation of WNV in cell culture medium over several days at an ambient temperature (28°C). Aliquots of WNV were removed from the 37°C ELISA wash buffer at 5, 15, 30, and 60 min for the former experiment, while daily aliquots of medium were sampled for the latter experiment. No virus was detected in the wash buffer at 30 and 60 min, while virus was readily detected from cell culture medium over this time. In addition, titers of WNV consistently dropped over a 7-day period at 28°C compared to control suspensions of virus held at 4°C. These observations indicate that WNV is readily inactivated in the presence of detergent-containing buffers. Furthermore, the viability loss at ambient temperature suggests that WNV is easily inactivated during routine transportation and testing of human body fluids such as serum and cerebrospinal fluid.