Cross-Species Disease Transmission describes the processes by which infectious agents move between animal species and humans, often initiating novel disease events. These transmission events arise from complex interactions among pathogens, hosts, and environments, and they are shaped by ecological disruption, animal husbandry practices, wildlife trade, and human behavior. Understanding cross-species transmission is central to preventing emerging infectious threats and strengthening global health preparedness.

Scientific investigation of cross-species disease transmission integrates ecology, veterinary science, virology, and epidemiology. Pathogens circulate within animal reservoirs and may adapt through genetic changes that facilitate infection of new hosts. Human activities such as land-use change, agricultural intensification, and increased contact with wildlife elevate opportunities for interspecies contact. These mechanisms and risk factors are frequently examined at Infectious Diseases Conferences, where One Health perspectives inform strategies to reduce spillover risk.

From a mechanistic standpoint, zoonotic spillover events occur when pathogens overcome species barriers through receptor compatibility, immune evasion, or changes in exposure pathways. Environmental stressors can alter host susceptibility and pathogen shedding, while social and economic drivers influence contact rates. Identifying high-risk interfaces—such as wildlife markets, farming systems, and peri-urban habitats—enables targeted surveillance and intervention.

Once cross-species transmission occurs, onward transmission dynamics determine whether a pathogen establishes sustained spread in the new host population. Factors such as transmission efficiency, population immunity, and social networks shape outbreak potential. Early detection and rapid response are critical to interrupt transmission chains before widespread dissemination. Integrating animal and human health data enhances situational awareness and response coordination.

Prevention strategies focus on reducing risky contact, improving biosecurity, and strengthening surveillance at human–animal interfaces. Measures include safer farming practices, regulation of wildlife trade, habitat conservation, and education of communities at risk. Veterinary vaccination, monitoring of animal health, and environmental management further reduce the likelihood of pathogen amplification and spillover.

Future approaches emphasize predictive modeling, genomic analysis, and integrated surveillance to anticipate cross-species transmission risks. Advances in data integration and field diagnostics support earlier identification of threats and more precise interventions. Sustained attention to cross-species disease transmission strengthens preparedness, protects ecosystems, and supports resilient health systems capable of addressing emerging infectious challenges.