The global network of domestic mammal hosts and zoonotic bacteria: implications for disease transmission and detection

Zoonotic diseases, defined as those transmitted from animals to humans, represent over 75% of emerging infectious diseases and pose ongoing challenges to public health. Understanding the structure of host–pathogen interactions is critical for anticipating and mitigating such threats. In this study, we analysed the global bipartite network formed by zoonotic bacteria and their domestic mammal hosts. A bipartite network links two distinct sets of nodes – in this case, bacteria and hosts – through documented interactions. We aimed to 1) describe the structure of this host–bacteria (H–B) network using ecological network metrics, and 2) assess whether host traits, namely time since domestication and phylogenetic proximity to humans, predict the number of associated zoonotic bacteria per host species. The network, built from literature‐based associations involving 24 domestic mammals and 51 zoonotic bacteria, exhibited high nestedness (a pattern where specialist bacteria infect subsets of hosts used by generalist bacteria) and low modularity (indicating weak compartmentalisation into distinct host–pathogen clusters) compared with null models. This suggests a non‐random, core–periphery structure. Hosts with longer domestication histories hosted significantly more bacterial species, whereas phylogenetic distance from humans had no significant effect. These findings suggest that early‐domesticated hosts may act as key nodes for pathogen accumulation and redistribution. The nested architecture also revealed likely ‘missing links' (unreported but plausible host–pathogen interactions), offering a practical basis for targeted surveillance. While network analysis is already established in zoonotic research, our global‐scale findings highlight its continued potential to uncover structure and dynamics in increasingly complex host–pathogen systems.