Abstract
The protection afforded by similar concentrations of different dengue virus serotypes against a subsequent challenge of West Nile virus was studied in hamsters. The New Guinea C strain of dengue 2 virus gave the best protection. It was found that the anamnestic neutralizing antibody response induced by the challenge West Nile virus against West Nile virus in hamsters, previously immunized with dengue 2 virus, might play a major role in the cross-protection observed in this system.