Lethal exposure: An integrated approach to pathogen transmission via environmental reservoirs.
To mitigate the effects of zoonotic diseases on human and animal populations, it is critical to understand what factors alter transmission dynamics. Here we assess the risk of exposure to lethal concentrations of the anthrax bacterium, Bacillus anthracis, for grazing animals in a natural system over time through different transmission mechanisms. We follow pathogen concentrations at anthrax carcass sites and waterholes for five years and estimate infection risk as a function of grass, soil or water intake, age of carcass sites, and the exposure required for a lethal infection. Grazing, not drinking, seems the dominant transmission route, and transmission is more probable from grazing at carcass sites 1-2 years of age. Unlike most studies of virulent pathogens that are conducted under controlled conditions for extrapolation to real situations, we evaluate exposure risk under field conditions to estimate the probability of a lethal dose, showing that not all reservoirs with detectable pathogens are significant transmission pathways.
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0361 Oslo, Norway.|Department of Biological Sciences, State University of New York, Albany, New York 12222, USA.|Department of Environmental Science, Policy and Management, University of California, Berkeley, 137 Mulford Hall, Berkeley, CA 94720-3112, USA.
Wendy C
WC
Turner
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0361 Oslo, Norway.
Kyrre L
KL
Kausrud
Institute of Animal Sciences, Department of Environmental and Animal Hygiene, University of Hohenheim, Hohenheim, Germany.
Wolfgang
W
Beyer
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0361 Oslo, Norway.
W Ryan
WR
Easterday
Department of Biological Sciences, Faculty of Science, University of Namibia, Windhoek, Namibia.
Zoë R
ZR
Barandongo
Institute of Animal Sciences, Department of Environmental and Animal Hygiene, University of Hohenheim, Hohenheim, Germany.
Elisabeth
E
Blaschke
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0361 Oslo, Norway.|Department of Biological Sciences, Faculty of Science, University of Namibia, Windhoek, Namibia.|Etosha Ecological Institute, Ministry of Environment and Tourism, Etosha National Park, PO Box 6, Okaukuejo, Namibia.
Claudine C
CC
Cloete
Institute of Animal Sciences, Department of Environmental and Animal Hygiene, University of Hohenheim, Hohenheim, Germany.|Institute of International Animal Health, Free University of Berlin, Königsweg 67, 14163 Berlin, Germany.
Judith
J
Lazak
Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA.
Matthew N
MN
Van Ert
Department of Environmental Science, Policy and Management, University of California, Berkeley, 137 Mulford Hall, Berkeley, CA 94720-3112, USA.|Genome Center and Department of Evolution and Ecology, University of California, Davis, CA, USA.
Holly H
HH
Ganz
Peter C B
PC
Turnbull
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, P.O. Box 1066 Blindern, 0361 Oslo, Norway.
Nils Chr
NC
Stenseth
Department of Environmental Science, Policy and Management, University of California, Berkeley, 137 Mulford Hall, Berkeley, CA 94720-3112, USA.|School of Mathematical Sciences, University of KwaZulu-Natal, Private Bag X54001, Durban 4000, South Africa.
Wayne M
WM
Getz
D000818:Animals; D000881:Anthrax / Q000635:transmission / Q000662:veterinary*; D001408:Bacillus anthracis / Q000302:isolation & purification*; D058491:Bacterial Load; D018562:Disease Transmission, Infectious; D012988:Soil Microbiology; D013997:Time Factors; D014871:Water Microbiology; D015047:Zoonoses / Q000635:transmission*