NR AVXR
AU McIntyre,K.M.; Gubbins,S.; Goldmann,W.; Stevenson,E.; Baylis,M.
TI The time-course of a scrapie outbreak
QU BMC Veterinary Research 2006 Jun 13; 2: 20
IA http://www.biomedcentral.com/1746-6148/2/20
PT journal article; research support, non-u.s. gov't
AB BACKGROUND: Because the incubation period of scrapie has a strong host genetic component and a dose-response relationship, it is possible that changes will occur during an outbreak, especially in the genotypes of cases, age-at-onset of disease and, perhaps, the clinical signs displayed. We investigated these factors for a large outbreak of natural scrapie, which yielded sufficient data to detect temporal trends. RESULTS: Cases occurred mostly in two genotypes, VRQ/VRQ and VRQ/ARQ, with those early in the outbreak more likely to be of the VRQ/VRQ genotype. As the epidemic progressed, the age-at-onset of disease increased, which reflected changes in the genotypes of cases rather than changes in the age-at-onset within genotypes. Clinical signs of cases changed over the course of the outbreak. As the epidemic progressed VRQ/VRQ and VRQ/ARQ sheep were more likely to be reported with behavioural changes, while VRQ/VRQ sheep only were less likely to be reported with loss of condition. CONCLUSION: This study of one of the largest scrapie outbreaks in the UK allowed investigation of the effect of PrP genotype on other epidemiological parameters. Our analysis indicated that, although age-at-onset and clinical signs changed over time, the observed changes were largely, but not exclusively, driven by the time course of the PrP genotypes of cases.
MH Aging; Animals; Disease Outbreaks/*veterinary; Genetic Predisposition to Disease; Great Britain/epidemiology; Scrapie/*epidemiology; Sheep/*genetics; Time Factors
AD Institute for Animal Health, Pirbright Laboratory, Ash Road, Pirbright, Surrey, UK. marie.mcintyre@bbsrc.ac.uk
SP englisch
PO England