Domestic goose as a model for West Nile virus vaccine efficacy

West Nile virus (WNV) is an emergent pathogen in the Americas, first reported in New York during 1999, and has since spread across the USA, Central and South America causing neurological disease in humans, horses and some bird species, including domestic geese. No WNV vaccines are licensed in the USA for use in geese. This study reports the development of a domestic goose vaccine efficacy model, based on utilizing multiple parameters to determine protection. To test the model, 47 geese were divided in two experiments, testing five different vaccine groups and two sham groups (challenged and unchallenged). Based on the broad range of results for individual metrics between the Challenged-Sham and Unchallenged-Sham groups, the best parameters to measure protection were Clinical Pathogenicity Index (CPI), plasma virus positive geese on days 1–4 post-inoculation and plasma virus titers, and brain histological lesion rates and severity scores. Compared to the Challenged-Sham group, the fowlpox virus vectored vaccine with inserts of WNV prM and E proteins (vFP2000) provided the best protection with significant differences in all five metrics, followed by the canarypox virus vectored vaccine with inserts of WNV prM and E proteins (vCP2018) with four metrics of protection, recombinant vCP2017 with three metrics and WNV E protein with one. These data indicate that domestic geese can be used in an efficacy model for vaccine protection studies using clinical, plasma virological and brain histopathological parameters to evaluate protection against WNV challenge.