Mathematics and big data to combat cholera


Photo by DVIDSHUB - USS Iwo Jima assists Haiti after Hurricane Tomas

This year, the Ca’ Foscari University of Venice Prize for Research went to professor Enrico Bertuzzo, leader of an international team that has developed a mathematical model able to provide a projection on the transmission of cholera. The prize was given during the ceremony for the inauguration of the 149th academic year.

Tested during the 2000 epidemic in South Africa and the 2005 epidemic in Senegal, the model has been given to Doctors Without Borders to evaluate the best reaction to the uncontrollable contagion in Haiti after Hurricane Matthew hit in last October. Within a few weeks over 11 thousand cases of suspected contagion were registered.

The research has given responses in real-time: the World Health Organization has been able to take advantage of the scenarios calculated by the model to guide the campaign for vaccination for a million haitians. Projections and verified data on the epidemic have been made available online by Doctors Without Borders to provide updated information for those attending the site.

At that point in time, in October 2016, Enrico Bertuzzo, a thirty-seven year-old from Vicenza, became employed as an associate professor in the Department for Enviromental Sciences, Informatics and Statistics at Ca’ Foscari, from the EPFL Polytechnic University of Lausanne (Switzerland) where for eight years, as both a post-doctoral student and as a researcher, he developed the model with the collaboration of microbiologists and epidemiologists specializing in Vibrio Cholerae and its effects.

An environmental engineer with a doctorate in hydrology, Bertuzzo has dedicated his research activity to the development of the first spatial model for the diffusion of cholera that taks into account the distribution and movement of people and hydrologic transportation.

In fact, to monitor the movement of the Senegalese during the explosion of the epidemic in 2005, the locations of 150 thousand mobile phones are included in the model, data anonymously published by phone company Orange for a Data for Development Challenge, discovering that the main culprit for the infection was an assembly of millions of pilgrims, who had then transmitted the disease into their local villages. The study was published in the Proceedings of the National Academy of Sciences (PNAS).

Cholera is spread through bacteria in contaminated water, as doctor John Snow discovered when annotating the places of the deceased during the epidemic in London in 1854, noting the correspondence between the sources of contaminated water. Over 160 years later, there is still a lot to understand about the evolution of epidemics, above all how to prevent and contain the contagions, especially in developing countries.

“The bacterium can spread through rivers after the rain washes away lavatory waste” – Bertuzzo explained. “but it is not enough to study the hydrology to understand the epidemic. We have demonstrated how it is possible and crucial to observe the movements and gatherings of people and include this information in the model. The telephonic big data are unprecedented tools to calculate in detail where the disease is heading and formulate the best response strategy”.