Wide-range protection against avian reovirus conferred by vaccination with representatives of four defined genotypes

Many isolates of the contagious avian reovirus have been characterized, mainly based on the sequence of their sigma C protein. These isolates have been classified into four genotypes. Currently available vaccines are of limited effectiveness, likely due to the existence of many variants. The aim of this study was to test the efficacy of a vaccine consisting of a mixture of prototypes (representatives) of the four defined genotypic groups of avian reovirus. The prototypes were selected based on their distance from the isolates within each genotype. All prototypes were found to be virulent. Antibodies produced against each of the prototypes neutralized all members of its genotype. Birds were then vaccinated with a mixture of the four prototypes. Results suggest that the 4-valent vaccine can prevent disease and confer broad protection against field isolates of avian reovirus.