EPFL scientists create the world's first map of regions where the prevalence of hepatitis E is highest

EPFL scientists have created the world's first map of regions where the prevalence of hepatitis E virus (HEV) is highest. They hope that their card – available for free online – will help governments and NGOs to design more effective prevention campaigns based on reliable data, including the creation of refugee camps. The scientists' research has just been published in Scientific reports.

In Europe, China, Japan and North America, the main way to get HEV is to eat undercooked pork. The resulting illness is not usually life-threatening. However, in Mexico, India, Africa and most Asian countries, HEV is contracted by coming into contact with water from a river or well contaminated with water. feces. According to the World Health Organization, there are about 20 million HEV infections worldwide each year and about 50,000 deaths from the disease. Epidemics of hepatitis E are particularly deadly for pregnant women and usually occur after heavy rains and floods or after months of drought.

Machine learning

To build their map, EPFL scientists have collected data on all outbreaks of hepatitis E recorded worldwide since 1980 and on environmental statistics such as temperature, humidity of the soil and rainfall over the same period. They also took into account geographical location, population density and rate of evapotranspiration, or the amount of water that evaporates during a drought. Evapotranspiration is important because the more this occurs, the more intestinal pathogens are highly concentrated in the remaining contaminated water – a water often used for cooking, washing or even religious ceremonies.

Through machine learning, scientists were able to badyze all the data and obtain actionable results.

Our study confirmed that the most at risk areas are those with high population densities, heavy seasonal precipitation, and high evapotranspiration rates. "

Anna Carratalà, scientist at the Laboratory of Environmental Chemistry of EPFL and lead author of the study

Its co-author, Stéphane Joost, works at the Geographical Information Systems Laboratory of EPFL. "One way to reduce this risk is to artificially increase river flows during the hottest and driest periods of the year."

The need for more data

EPFL scientists have done a tremendous job in collecting data from a number of online sources. Yet, their map represents only one step in the development of prevention campaigns in high-risk areas. For example, their map shows that it is urgent to take action in northern India. According to Carratalà, the next step would be to add to their dataset information on annual HEV concentrations in the Ganges, as well as the number of cases of hepatitis E recorded in local hospitals. This would give them a better idea of ​​how environmental factors are affecting hepatitis E outbreaks in this region.

The scientists worked with the National Institute of Epidemiology of India to collect data on the country. In a new project, they will examine how human activity affects HEV and other contaminant levels – such as antibiotic-resistant genes – in the Rhone, Switzerland, and compare them with concentrations found in the Ganges. .