Researchers have shown that looking at movements of operators and vehicles between farms in the same way we look at contacts in social networks can help explain the spread of dangerous infectious diseases of livestock, such as foot-and-mouth disease and avian influenza. The study, produced by Dr Gianluigi Rossi from the Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna and colleagues, have shown that the network of contacts originated from on-farm visits by veterinarians in dairy farms of Northern Italy displays hidden features that cannot be detected by simply looking at the frequency of visits and unveils patterns of infection otherwise unexplained. The authors discovered that veterinarians' movements produce an unexpectedly large number of potentially infectious contacts between farms that can quickly spread dangerous livestock diseases.