Ecological Origins of Novel Human Pathogens

Abstract

A systematic literature survey suggests that there are 1399 species of human pathogen. Of these, 87 were first reported in humans in the years since 1980. The new species are disproportionately viruses, have a global distribution, and are mostly associated with animal reservoirs. Their emergence is often driven by ecological changes, especially with how human populations interact with animal reservoirs. Here, we review the process of pathogen emergence over both ecological and evolutionary time scales by reference to the "pathogen pyramid." We also consider the public health implications of the continuing emergence of new pathogens, focusing on the importance of international surveillance.

From Risk Assessment to Knowledge Mapping: Science, Precaution, and Participation in Disease Ecology

“…Of course, there is always the broader possibility of the emergence of entirely novel pathogens. Indeed, over 70% of new infectious diseases affecting humans that have emerged over the last 30 years have emerged unexpectedly from nonhuman animal populations (Woolhouse andGaunt 2007, Jones et al 2008). As acknowledged in a different context from a rather unexpected source, this is the domain of Donald Rumsfeld"s famous "unknown unknowns" (Rumsfeld 2002).…”

Nipah virus infection: current scenario

“…implies that disease emergence and spread are not limited by geographical boundaries. In many cases the animals are found to be the source of infection for human infection [95]. Only 87 out of 1,399 human pathogen have been first reported in humans in the years since 1980 [95].…”

“…In many cases the animals are found to be the source of infection for human infection [95]. Only 87 out of 1,399 human pathogen have been first reported in humans in the years since 1980 [95]. India's fast-growing human population and resulting increasing animal-human interactions, combined with changing environmental conditions and inadequate sanitation and regulation, have made India one of the world's top hotspots for livestock diseases, including zoonotic diseases-those that pass from animals to humans and which make up 75 % of all human diseases.…”

Whataroa virus four decades on: emerging, persisting, or fading out?

“…Recent analyses indicate that viruses (together with prions) have been involved in 25Á44% of disease emergence events (Cleaveland et al 2001;Taylor et al 2001;Woolhouse & Gowtage-Sequeria 2005;Jones et al 2008). In addition, a disproportionately large number of the new species of human pathogens reported in the last three decades have been viruses (Woolhouse & Gaunt 2007). Emergence of disease-causing viral agents is also generally one of the top concerns of wildlife, domestic animal, and public health agendas (Bricaire & Bossi 2006;Heeney 2006;Mackereth et al 2007).…”

“…In particular, arboviral diseases vectored by mosquitoes are among the most important of the emerging infectious disease problems facing the world (Gubler 2001;Mackenzie et al 2004), with emergence generally comprising the spread (and often reemergence) of existing viral agents (Gubler 2002). This is in contrast to host-shifts from wildlife, being the most common mechanism of emergence for both directly transmitted viral (Woolhouse & Gaunt 2007), and other major human infectious diseases (Wolfe et al 2007). Such spread and re-emergence is due to the mosquito vectors of these disease-causing agents typically being highly sensitive to changes in environmental conditions (Liehne 1988;Rogers & Randolph 2000;Kovats et al 2001) and land use (Patz et al 2004;Hui 2006), and highly prone to anthropogenic dissemination to new geographic areas (Lounibos 2002;Tatem et al 2006).…”