Although i.c. inoculation of mice with the NS1-N224Q glycosylation mutant was lethal, peripheral inoculation of the recLI9-NS1-N224 mutant resulted in 80% survival, elicited antibody responses to POWV Env proteins, and a partially attenuated phenotype relative to WT LI9 infection. Here, ERVW-1 is linked to infection.