Asymptomatic deer excrete infectious prions in faeces
Gültekin Tamgüney1,2, Michael W. Miller3, Lisa L. Wolfe3, Tracey M. Sirochman3, David V. Glidden4, Christina Palmer1, Azucena Lemus5, Stephen J. DeArmond1,5 & Stanley B. Prusiner1,2
1.Institute for Neurodegenerative Diseases, 2.Department of Neurology, University of California, San Francisco, California, 94143 USA 3.Colorado Division of Wildlife, Wildlife Research Center, Fort Collins, Colorado, 80526 USA 4.Department of Epidemiology and Biostatistics, 5.Department of Pathology, University of California, San Francisco, California, 94143 USA Correspondence to: Stanley B. Prusiner1,2 Correspondence and requests for materials should be addressed to S.B.P. (E-mail: Email: firstname.lastname@example.org.)
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Infectious prion diseases1—scrapie of sheep2 and chronic wasting disease (CWD) of several species in the deer family3, 4—are transmitted naturally within affected host populations. Although several possible sources of contagion have been identified in excretions and secretions from symptomatic animals5, 6, 7, 8, the biological importance of these sources in sustaining epidemics remains unclear. Here we show that asymptomatic CWD-infected mule deer (Odocoileus hemionus) excrete CWD prions in their faeces long before they develop clinical signs of prion disease. Intracerebral inoculation of irradiated deer faeces into transgenic mice overexpressing cervid prion protein (PrP) revealed infectivity in 14 of 15 faecal samples collected from five deer at 7–11 months before the onset of neurological disease. Although prion concentrations in deer faeces were considerably lower than in brain tissue from the same deer collected at the end of the disease, the estimated total infectious dose excreted in faeces by an infected deer over the disease course may approximate the total contained in a brain. Prolonged faecal prion excretion by infected deer provides a plausible natural mechanism that might explain the high incidence and efficient horizontal transmission of CWD within deer herds3, 4, 9, as well as prion transmission among other susceptible cervids.
Wednesday, June 11, 2008
Transmission and Detection of Prions in Feces
The Journal of Infectious Diseases 2008;198:81–89 © 2008 by the Infectious Diseases Society of America. All rights reserved. 0022-1899/2008/19801-0015$15.00 DOI: 10.1086/588193