Infectious Bursal Disease Virus Genotypic Diversity from Poultry in Latin America

Infectious bursal disease virus (IBDV) is a pathogen that causes Gumboro disease in young chickens. Vaccine strains and field IBDV genotypes are disseminated in chickens from commercial poultry farms worldwide. This study aimed to detect the field IBDV genotypic diversity in poultry farms in Latin America, mainly in Brazil. Bursal samples from 69 broiler flocks in eleven Latin American countries were obtained between 2015 and 2025. All 69 samples tested were positive for IBDV; the VP2 (segment A) and VP1 (segment B) genes were sequenced. Phylogenetic and amino acid substitution analyses were performed with large genetic datasets, including previously identified IBDV genotypes worldwide. The results revealed four A (A1, A2, A3, and A4) and three B (B1, B2, and the candidate B6) genogroups in Latin America. Furthermore, genotypes A1B1 (1.4%), A2B1 (59.4%), A3B2 (20.3%), A3B6 (2.9%), and A4B1 (15.9%) were identified. A2B1 could be subdivided into A2aB1a (24.4%), A2bB1a (29.3%), A2dB1b (19.5%), and A2eB1a (26.8%). In Brazil, the field genotypes A3B2, A4B1, and A3B6 were demonstrated. These findings highlight an important IBDV genotypic diversity in Latin American countries and reinforce the need for continuous molecular surveillance to support control and vaccination programs.