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

Abstract

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.

Keywords: Biodiversity; Infectious diseases; Livestock; Outbreaks; Public health.

Fig. 1

Maps and spatial autocorrelation (small insert for each map) of (A) the number of assessed species, (B) the number of endangered species; (C) the richness of infectious diseases reported; (D) the number of outbreaks of human infectious diseases; (E) the number of cattle; (F) the number of outbreaks of animal infectious diseases (data from GIDEON, ICUN and FAOSTAT).

Fig. 2

Results of General additive modelling (GAM). The first model explained the number of infectious and parasitic infectious diseases in humans with the number of wildlife species (A) and the number of surveys investigating human infectious diseases (B) by country (see Fig. 1) taking into account the spatial dependancy (using the country centroids) (see Table 1, model 1). The second model explained the ratio of the number of outbreaks of infectious in humans, to the number of infectious and parasitic infectious diseases, with the ratio of the number of wildlife species (C), to the number of wildlife species, and the number of cattle (D) by country (see Fig. 1) taking into account the spatial dependancy (using the country centroids) (see Table 1, model 2) (data from GIDEON, ICUN and FAOSTAT).

Fig. 3

A. Number of outbreaks of human diseases from 1960 to 2019 (data obtained from GIDEON). B. Number of outbreaks of animal diseases from 2006 to 2019 (data obtained from WAHIS – OIE). C. Number of heads of cattle from 1960 to 2016 (data obtained from FAOSTAT). D. Number of the number of threatened wildlife species (all categories of IUCN) from 2000 to 2019 (data obtained from IUCN).

Fig. 4

A. Association between the number of head of cattle and the number of outbreaks of human diseases from 1960 to 2019. B. Association between the number of head of cattle and the number of outbreaks of animal diseases from 2006 to 2019. C. Association between the number of threatened wildlife species and the number of outbreaks of human diseases from 2000 to 2019. C. Association between the number of threatened wildlife species and the number of outbreaks of animal diseases from 2006 to 2019.

Fig. 5

Results of Structural equation modelling (A, Table 2) on temporal trends from 2000 to 2016, with significant positive partial correlations between: (B) the number of endangered wildlife species and assessed species; (C) the number of outbreaks of human diseases and the number of cattle; (D) the number of endangered wildlife species and number of cattle (data from GIDEON, ICUN and FAOSTAT).