Diverse soil microbial communities may help suppress pathogens naturally, acting as a biological barrier against their establishment and spread, according to a new study.
Professor Brajesh Singh, from The University of Western Australia's School of Agriculture and Environment and Institute of Agriculture, was lead author of the study published in Cell Host & Microbe, which examined human pathogens in soils.
"The One Health concept recognises that the health and well-being of humans are closely linked to the health of other ecosystem components, including soil, plants and animals," Professor Singh said.
"Soil is therefore far more than the ground beneath our feet – it is a living system that influences food safety, ecosystem stability and human disease risk."
Researchers analysed 1,602 soil samples from 59 countries to produce a global map and hotspot of the dominant human bacterial pathogens living in soils and found links between prevalence of pathogens and a global pattern of mortality from infectious diseases.
"Soils are not only a source of nutrients that support plant growth, but also a natural habitat for many human pathogens, such as Listeria monocytogenes and Salmonella enterica, which can cause food poisoning, and Burkholderia pseudomallei, which causes melioidosis," he said.
"Despite their importance for food safety and human health, we still know very little about the global distribution, diversity and ecological preferences of human pathogens in soils."
First author Dr Chao Xiong, an incoming research fellow at UWA, said the pathogens were found to be more common in wet ecosystems, especially tropical and temperate regions, and were particularly abundant in cropland soils.
"This is important because agricultural soils sit at the interface between environmental health, food production and human exposure," Dr Xiong said.
Further modelling suggested many human pathogens would increase in prevalence under projected climate change scenarios.
"These findings show soil microbial communities not only support agricultural productivity but also play an important role in human health," Professor Singh said.
"Protecting soil biodiversity could therefore benefit not only sustainable agriculture but also public health.
"In the future, this work could help guide pathogen surveillance, risk prediction and land management strategies aimed at reducing disease outbreaks."
