Soil is rarely discussed as public-health infrastructure, yet a global study in Cell Host and Microbe suggests it should be. An international team including KAUST's Fernando Maestre analysed 1,602 soil samples from 59 countries, identifying 80 bacterial taxa capable of infecting humans and classing 25 of them as dominant: widespread, present in at least 80 per cent of samples and abundant within the soil pathogen community.
Combining shotgun metagenomics, quantitative PCR, whole-genome analyses and machine learning, the researchers mapped where these bacteria occur today and where they may thrive under future climate scenarios. Temperature correlated positively with the relative abundance of dominant pathogens, implying warming could expand their range, and pathogen loads were highest in wet tropical and temperate ecosystems and in cropland soils. Strikingly, the predicted distribution of the Mycobacterium tuberculosis complex resembled the World Health Organization's global tuberculosis map.
The most hopeful finding is protective: soils with more diverse microbiomes harboured fewer pathogens, suggesting biodiversity itself suppresses them. The authors argue that protecting soil health belongs within One Health strategies alongside wastewater surveillance and clinical monitoring, particularly in flood-prone and intensively farmed regions. The maps do not forecast outbreaks, since infection depends on exposure, sanitation and healthcare, but they offer a baseline for environmental early-warning systems.