Reframing transboundary animal diseases: a systems approach

Transboundary animal diseases (TADs) represent a persistent and growing threat to global animal health, food security, rural economies, and human health. The study of TADs has remained largely pathogen-specific, with limited synthesis across ecological and epidemiological contexts. This review addresses that gap by proposing a conceptual framework that characterizes TAD transmission from (i) managed animal environments (e.g., farms) in a source country, via (ii) transboundary movement, to (iii) managed animal environments in a recipient country. Transboundary movements include legal and unregulated trade, wildlife migration, nomadic herding, and non-nomadic human travel. For each movement pathway, we synthesize the literature on relevant TADs, illustrate our framework with examples, and highlight where interventions and policies can be applied to individual and collective TAD issues.