Research has shown that analysing movements of operators and vehicles between farms in the same way we do contacts in social networks can help explain the spread of dangerous infectious diseases of livestock, such as foot-and-mouth disease and avian influenza.
In findings published in last month’s issue of PLOS Computational Biology, Dr Gianluigi Rossi from the Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna, and colleagues, found that visits by veterinarians to dairy farms located in Northern Italy led to an unexpectedly large number of potentially infectious contacts between farms capable of quickly spreading dangerous livestock diseases.
The research, made possible by the availability of high-resolution data in space and time on veterinarian movements in the study area, shed light on the actual significance of operator movements in disease spread, a still poorly understood topic due to the highly diverse and complex nature of such movements, and to privacy issues in data collection.
The researchers compared the role of veterinarian movements on diseases spread with those of animal exchanges between farms, which is recognised as the most effective transmission route for livestock infectious diseases. They found that co-occurrence of operator movements and animal exchanges is synergistic, largely amplifying the potential for disease propagation.
The study also demonstrated how multilayer network analysis substantially improves the way diseases spread can be described, thus contributing to their control.
Dr Rossi and his team hope their research will contribute to the development of more accurate tools for predicting the spread of livestock diseases, and help implement more effective biosecurity measures on farms.