Are disease reservoirs special? Taxonomic and life history characteristics

Abstract

Pathogens that spill over between species cause a significant human and animal health burden. Here, we describe characteristics of animal reservoirs that are required for pathogen spillover. We assembled and analyzed a database of 330 disease systems in which a pathogen spills over from a reservoir of one or more species. Three-quarters of reservoirs included wildlife, and 84% included mammals. Further, 65% of pathogens depended on a community of reservoir hosts, rather than a single species, for persistence. Among mammals, the most frequently identified reservoir hosts were rodents, artiodactyls, and carnivores. The distribution among orders of mammalian species identified as reservoirs did not differ from that expected by chance. Among disease systems with high priority pathogens and epidemic potential, we found birds, primates, and bats to be overrepresented. We also analyzed the life history traits of mammalian reservoir hosts and compared them to mammals as a whole. Reservoir species had faster life history characteristics than mammals overall, exhibiting traits associated with greater reproductive output rather than long-term survival. Thus, we find that in many respects, reservoirs of spillover pathogens are indeed special. The described patterns provide a useful resource for studying and managing emerging infectious diseases.

Predicting the global mammalian viral sharing network using phylogeography

“…It is possible that the high predicted centrality of known hosts was due partly to selective sampling (i.e., viral researchers are more likely to sample wide-ranging and common host species that also share viruses with many other species 10,20 ). This possibility is supported by the greater link number for species that appear in both EID2 and our dataset rather than in only one of the two, as these species are presumably more well-known ( Figure 2C).…”

“…Furthermore, host range is inadequately characterized even for the best-studied viruses [5][6][7] . To help prioritise pathogen discovery efforts and zoonotic disease surveillance in wildlife, studies have linked high (zoonotic) parasite diversity with certain host taxa, such as rodents and bats 5,8 , and/or with phenotypic host traits such as reproductive output 9,10 . Viral diversity has also been associated with host macroecological traits including geographic range size 11 and sympatry with other mammals 5 .…”

Going to Bat(s) for Studies of Disease Tolerance

“…Given the diversity of the Chiroptera order (Figure 1), we may simply see more bat viruses because there are so many (>1,300) species of bats (31). However, even when accounting for the fact that they make up ∼20% of extant terrestrial mammals, bats are overrepresented as reservoir hosts of pathogens with a high potential for spilling into human populations (32,33). In fact, no known predictors that have been described to impact the likelihood of crossing the species barrier, including reservoir host ecology, phylogenetic relatedness to humans or frequency of reservoir-human contact, explain this pattern (32).…”

Phylogenetic factorization of mammalian viruses complements trait-based analyses and guides surveillance efforts

“…Following Plowright et al (Plowright et al 2017), we next determined zoonotic transmission through the three primary routes of pathogen release: vector-borne transmission, reservoir excretion, and reservoir host slaughter. We expanded datasets from (Olival et al 2017), (Jones et al 2008) and (Plourde et al 2017) by screening the same texts and with a similar targeted GoogleScholar search. Pathogen release was recorded as three binary covariates for whether zoonotic transmission occurs through excretion, slaughter, or vectors; these categories are not mutually exclusive.…”