How can species jumps in avian influenza be detected? The solution is FluWarning, a digital system that identifies abnormal evolution of influenza viruses. Developed by a team from the Polytechnic University of Milan and the University of Milan, the system examines the genetic sequence of viruses for subtle yet meaningful variations that could signal potential spillover: the transmission of the virus from one species to another, such as from birds to livestock or humans. The research results were published in the journal 'Science Advances'. Between 2024 and 2025, two genotypes of the H5N1 virus were linked to multiple epidemics in the United States, resulting in numerous dairy cattle infections with the avian influenza virus. "FluWarning has detected concentrations of viral activity across multiple US states, notably California, where a state of emergency was declared on December 18, 2024, owing to the potential threat of livestock contamination. The researchers clarify that, in certain instances, the alerts generated by the system were received prior to the official reports", researchers explain. FluWarning further identified specific mutations within the hemagglutinin (HA) gene, a protein responsible for viral cellular entry, thereby facilitating the monitoring of Californian strain evolution and the identification of their unique genetic signatures. "FluWarning offers a significant step forward in the ability to detect viral alterations that could endanger animals and humans. Making this technology broadly available entails increasing worldwide surveillance on a health issue of critical collective interest", the experts conclude.