Emerging diseases, livestock expansion and biodiversity loss are positively related at global scale

Infectious diseases, biodiversity loss and livestock expansion are increasing globally, and examining patterns that link them is important for both public health and conservation. This study is a first attempt to analysis globally these patterns using General additive modelling and Structural equation modelling. A positive association between the number of infectious and parasitic diseases recorded in humans and the total number of animal species between nations was observed. A similar positive association between the number of outbreaks of human infectious diseases, corrected for the number of surveys, and the number of threatened animal species, corrected for the number of animal species, suggests that outbreaks of human infectious diseases are linked with threatened biodiversity. Results of the analyses over the longest period of the dataset (2000–2019) showed a positive correlation between the increasing number of cattle and the number of threatened species, a positive correlation between the increasing number of cattle and the number of outbreaks of human diseases, and a lack of correlation between the number of outbreaks and the number of threatened animal species. As a result, the growing importance of livestock on the planet, while threatening biodiversity, increasingly puts human and animal health at risk. This study calls for further analyses on the consequences of livestock expansion, which depends on several factors that vary by country, namely the growth of human population, changes in diet linked to the westernization of habits, agricultural industrialization and the integration into the world trade, but also the cultural values of livestock.