From smallpox to dengue: 200 years of integrated surveillance

Abstract The emergence of modern infectious disease surveillance can be traced back to early 19th-century notification systems, often introduced in parallel with the first mass vaccination campaigns. Archival sources from the city of Pavia, Northern Italy, document systematic case reporting for smallpox, measles, rubella, and epidemic typhus, revealing how public health authorities began to use data not only to control contagion but also to assess the effectiveness of anti-smallpox immunisation efforts. These early records offer compelling insights into the rationale and structure of disease surveillance during a period of major biomedical and social transition. Notably, notifications were not limited to human disease. Veterinary registers from the same archives report episodes of animal mortality, including mass deaths among ducks in the 1820s, which suggests an early awareness of zoonotic threats and possibly the circulation of avian diseases. This proto-One Health approach underscores how disease monitoring was already conceived across species boundaries. Fast-forward to the present, the same region has recently reported one of the first locally transmitted dengue outbreaks in continental Europe, with vector presence and climate conditions favouring endemic transmission. This geographical continuity reinforces the need to rethink surveillance systems for arboviruses by integrating vector monitoring, environmental indicators, and human case detection. The presentation will combine historical epidemiological data with contemporary scenarios to highlight how disease surveillance evolved from rudimentary registers to complex, multispecies systems. By bridging past and present, it supports a future-ready, One Health-oriented approach to epidemic intelligence.