Global biogeographic regions in a human‐dominated world: the case of human diseases

Abstract

. 2014. Global biogeographic regions in a human-dominated world: the case of human diseases.Ecosphere 5(11):143. http://dx.doi.org/10.1890/ES14-00201.1Abstract. Since the work of Alfred Russel Wallace, biologists have sought to divide the world into biogeographic regions that reflect the history of continents and evolution. These divisions not only guide conservation efforts, but are also the fundamental reference point for understanding the distribution of life. However, the biogeography of human-associated species-such as pathogens, crops, or even house guests-has been largely ignored or discounted. As pathogens have the potential for direct consequences on the lives of humans, domestic animals, and wildlife it is prudent to examine their potential biogeographic history. Furthermore, if distinct regions exist for human-associated pathogens, it would provide possible connections between human wellbeing and pathogen distributions, and, more generally, humans and the deep evolutionary history of the natural world. We tested for the presence of biogeographic regions for diseases of humans due to pathogens using country-level disease composition data and compared the regions for vectored and non-vectored diseases. We found discrete biogeographic regions for diseases, with a stronger influence of biogeography on vectored than non-vectored diseases. We also found significant correlations between these biogeographic regions and environmental or sociopolitical factors. While some biogeographic regions reflected those already documented for birds or mammals, others reflected colonial history. From the perspective of diseases caused by pathogens, humans have altered but not evaded the influence of ancient biogeography. This work is the necessary first step in examining the biogeographic relationship between humans and their associates.

Global biogeography of human infectious diseases

“…Pathogeography. Human infectious diseases exhibit clear biogeographic patterns at a global scale (27). The "pathogeographic" (28) patterns revealed here correlate with patterns of mammalian biodiversity and are broadly consistent with classic zoogeographic classifications, including regions reminiscent of Nearctic, Neotropical, Ethiopian/African, elements of the Saharo-Arabian, elements of the Mediterranean, Palearctic/Eurasian, Oriental, Australian, and Oceanian (15)(16)(17).…”

“…Considering that mammal assemblages correlate with disease assemblages after controlling for all other factors, even for disease classes that have no contemporary connection to mammals, this spatial structure is likely governed by the same processes that govern patterns of biodiversity more generally, which comprise a balance of historical events and local and regional processes, including diversification, geographic dispersal, and extinction (29). Biogeography thus provides a fundamental context in which all other factors contributing to the emergence and spread of infectious diseases are set, despite the unprecedented global availability and rising interconnectedness of humans as a host and the homogenizing forces of modern globalization (13,18,27).…”

Pathogeography: leveraging the biogeography of human infectious diseases for global health management

“…5C). The strongest β-diversity patterns, for example, can be observed in zoonotic, vector-borne and parasitic infectious diseases, likely due to a more dominant role of environmental factors and persistence of historical dispersal barriers limiting their geographic distributions, while patterns of humanspecific diseases are far more homogenous at the global scale (Smith et al 2007, Dunn et al 2010, Just et al 2014, Murray et al 2015, Jean et al 2016) (see also Box 3 Fig. panel D).…”

An equilibrium theory signature in the island biogeography of human parasites and pathogens

“…However, our understanding of the biogeography of human disease is surprisingly limited. Fewer than 10 infectious diseases have been mapped comprehensively (Hay et al, 2013), and we know less about the distributions of many human parasites and pathogens than we do about those of most rare birds (Just et al, 2014). As human populations grow and geographically change with urbanization and migration, exposing populations to novel social and ecological environments, there is an increasing need for first-order predictions to guide policy and future research.…”