Search results

Cross-species transmission (CST) of bacterial pathogens has major implications for human health, livestock, and wildlife management because it determines whether control actions in one species may have subsequent effects on other potential host species. The study of bacterial transmission has benefitted from methods measuring two types of genetic variation: variable number of tandem repeats (VNTRs) and single nucleotide polymorphisms (SNPs). However, it is unclear whether these data can distinguish between different epidemiological sce-narios. We used a simulation model with two host species and known transmis-sion rates (within and between species) to evaluate the utility of these markers for inferring CST. We found that CST estimates are biased for a wide range of parameters when based on VNTRs and a most parsimonious reconstructed phy-logeny. However, estimations of CST rates lower than 5% can be achieved with relatively low bias using as low as 250 SNPs. CST estimates are sensitive to several parameters, including the number of mutations accumulated since introduction, stochasticity, the genetic difference of strains introduced, and the sampling effort. Our results suggest that, even with whole-genome sequences, unbiased estimates of CST will be difficult when sampling is limited, mutation rates are low, or for pathogens that were recently introduced. ; We thank Steven Kalinowsky, Pauline Kamath, Gina K. Hi-mes Boor and Aaron Foley for comments on previous versions of this manuscript. We also thank two anonymous reviewers for their helpful comments. This work was sup-ported by the National Science Foundation and National Institutes of Health Ecology of Infectious Disease (grant number DEB-1067129), the United States Geological Survey and WGFD. The views and opinions in this article are those of the authors and should not be construed to represent any views, determinations, or policies of the US Government. Also, any use of trade, product, or firm names is for descriptive purposes only and does not imply ...

Some pathogens sustain transmission in multiple different host species, but how this epidemiologically important feat is achieved remains enigmatic. Sarcoptes scabiei is among the most host generalist and successful of mammalian parasites. We synthesize pathogen and host traits that mediate sustained transmission and present cases illustrating three transmission mechanisms (direct, indirect, and combined). The pathogen traits that explain the success of S. scabiei include immune response modulation, on-host movement capacity, off-host seeking behaviors, and environmental persistence. Sociality and host density appear to be key for hosts in which direct transmission dominates, whereas in solitary hosts, the use of shared environments is important for indirect transmission. In social den-using species, combined direct and indirect transmission appears likely. Empirical research rarely considers the mechanisms enabling S. scabiei to become endemic in host species-more often focusing on outbreaks. Our review may illuminate parasites' adaptation strategies to sustain transmission through varied mechanisms across host species. ; Australian Research CouncilAustralian Research Council [LP180101251]; Tasmanian Government Honours Scholarship in Wildlife Conservation by Department of Primary Industries, Parks, Water, and Environment ; Published version ; We thank Chris Burridge and Geoff While for feedback and assessment of an early draft. This work was supported by an Australian Research Council Link Project grant (no. LP180101251) to SC and the Tasmanian Government Honours Scholarship in Wildlife Conservation awarded to EB by the Department of Primary Industries, Parks, Water, and Environment. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the US government. ; Public domain authored by a U.S. government employee

Sarcoptic mange, a skin infestation caused by the mite Sarcoptes scabiei, is an emerging disease for some species of wildlife, potentially jeopardizing their welfare and conservation. Sarcoptes scabiei has a near-global distribution facilitated by its forms of transmission and use of a large diversity of host species (many of those with broad geographic distribution). In this review, we synthesize the current knowledge concerning the geographic and host taxonomic distribution of mange in wildlife, the epidemiological connections between species, and the potential threat of sarcoptic mange for wildlife conservation. Recent sarcoptic mange outbreaks in wildlife appear to demonstrate ongoing geographic spread, increase in the number of hosts and increased virulence. Sarcoptic mange has been reported in at least 12 orders, 39 families and 148 species of domestic and wild mammals, making it one of the most generalist ectoparasites of mammals. Taxonomically, the orders with most species found infested so far include Perissodactyla (67% species from the entire order), Artiodactyla (47%), and Diprotodontia (67% from this order). This suggests that new species from these mammal orders are likely to suffer cross-species transmission and be reported positive to sarcoptic mange as surveillance improves. We propose a new agenda for the study of sarcoptic mange in wildlife, including the study of the global phylogeography of S. scabiei, linkages between ecological host traits and sarcoptic mange susceptibility, immunology of individuals and species, development of control strategies in wildlife outbreaks and the effects of global environmental change in the sarcoptic mange system. The ongoing transmission globally and sustained spread among areas and wildlife species make sarcoptic mange an emerging panzootic in wildlife. A better understanding of sarcoptic mange could illuminate the aspects of ecological and evolutionary drivers in cross-species transmission for many emerging diseases. ; Australian Research Council Linkage ProgramAustralian Research Council [LP180101251]; Global Change Center at Virginia Tech; Center for Emerging, Zoonotic, and Arthropod-borne Pathogens at Virginia Tech; Arthropod-borne Pathogens at Virginia Tech ; Published version ; Mariana Castaneda-Guzman provided support in figure preparation. Anila Kalonia assisted with identifying reports of S. scabiei among host species. This research was supported by the Australian Research Council Linkage Program (LP180101251) to Scott Carver. Luis Escobar was supported by the Global Change Center and the Center for Emerging, Zoonotic, and Arthropod-borne Pathogens at Virginia Tech. Any use of trade, firm or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. ; Public domain authored by a U.S. government employee