Figure 9.

Viral shedding in vaccinated and control horses after EIV WT challenges: (A,B) Virus titers from nasopharyngeal swabs collected over 8 days after challenge with WT EIV were determined by immunofocus assay (FFU/mL) using an anti-NP monoclonal antibody (HB-65). Data represent individual results from each vaccinated (black) or control (gray) horse in group 1 (A) and group 2 (B). Dotted black lines represent the limit of detection of the assay (200 FFU/mL). (C,D) Embryonated chicken eggs were inoculated (100 μL/egg, in triplicate) with nasopharyngeal swabs collected over 8 days after challenge with WT EIVs and presence of challenge virus was evaluated by hemagglutination assay (HA). Horses were considered positive when at least one egg showed progeny virus growth. Bars represent the incidence of positive vaccinated (black) or control (gray) horses in group 1 (C) and group 2 (D). Number of eggs (n = 3) positive for the presence of WT EIV challenge virus are indicated at the bottom.