Research in this U19 Program is dependent on a system of central, standardized, and innovative analyses of West Nile virus (WNV) infection in cultured cells and in mice. The Virology Core is designed to meet these needs and standards and to provide infrastructure support for conducting WNV infections and virologic analysis for all five research projects of the Program. The Virology Core will be directed by Dr. Yueh-Ming Loo, an experienced virologist, biosafety expert, and a professional in the use of mice for virus infection studies. The Virology core will 1) Produce, conduct quality control, and conduct studies of centralized virus stocks used by the Program, 2) Coordinate and conduct all mouse infection studies within the Program, 3) Conduct in vitro and in vivo virologic analyses for the Program, and 4) Conduct and coordinate biosafety training of the Program staff. The Virology Core will be located in a centralized facility containing a suite of biosafety rooms for tissue culture and infected animal housing under and work under biosafety level 3 practices. The Core will work closely with Project Leaders and staff to design infection studies and conduct virologic analysis in support of the proposed studies. The Core will provide services of virus and virus product quantification, virus construction and characterization, serologic analyses, molecular diagnostic and quantification analyses, in vitro and in vivo infection support and analysis, and animal monitoring, clinical scoring, and the harvesting and possessing of tissues and cell samples. The Virology Core will interface with the Administrative Core to maintain records and training of personnel, prepare reports, and to communicate with Program staff.