Development of a contagious ecthyma vaccine for goats

Abstract

To identify a strain of contagious ecthyma virus from goats that possesses the appropriate characteristics for an effective vaccine for goats. 25 goat kids used for vaccine development and 100 goat kids used for evaluation of vaccine efficacy. 5 strains of contagious ecthyma virus were tested in a vaccination-challenge study to identify the best strain to be the seed strain for a contagious ecthyma vaccine. The vaccine derived from the chosen viral stain was tested at 2 concentrations for efficacy in a vaccination-challenge study. 2 of 5 viral strains induced moderate to severe scabs following infection, and 3 viral strains protected the goats from wild-type virus challenge following vaccination. Viral strain 47CE was selected as the seed source for the production of a contagious ecthyma vaccine because of the larger vaccine-to-challenge scab formation ratio. Vaccine 47CE protected all goat kids (48/48) following challenge with the wild-type contagious ecthyma virus; all goat kids (32/32) in the control group had scab formation following challenge with the wild-type contagious ecthyma virus, which indicated no protection following administration of vaccine diluent. A vaccine containing a caprine strain of contagious ecthyma virus used in goats appeared to provide the characteristics needed for an effective vaccine, including good scab production and protection from wild-type infection. This vaccine may potentially provide better protection for goats from contagious ecthyma than currently available vaccines labeled for sheep.