Abstract
Active disease surveillance during epidemics is of utmost importance in detecting and eliminating new cases quickly, and targeting such surveillance to high-risk individuals is considered more efficient than applying a random strategy. Contact tracing has been used as a form of at-risk targeting, and a variety of mathematical models have indicated that it is likely to be highly efficient. However, for fast-moving epidemics, resource constraints limit the ability of the authorities to perform, and follow up, contact tracing effectively. As an alternative, we present a novel real-time Bayesian statistical methodology to determine currently undetected (occult) infections. For the UK foot-and-mouth disease (FMD) epidemic of 2007, we use real-time epidemic data synthesized with previous knowledge of FMD outbreaks in the UK to predict which premises might have been infected, but remained undetected, at any point during the outbreak. This provides both a framework for targeting surveillance in the face of limited resources and an indicator of the current severity and spatial extent of the epidemic. We anticipate that this methodology will be of substantial benefit in future outbreaks, providing a compromise between targeted manual surveillance and random or spatially targeted strategies.
References
-
Anderson I. . 2008 Foot and mouth disease 2007: a review and lessons learned. London, UK The Stationary Office See http://www.cabinetoffice.gov.uk/fmdreview.aspx. Google Scholar -
Anderson R. M.& May R. M. . 1991 Infectious diseases of humans: dynamics and control New York, NY:Oxford University Press. Crossref, Google Scholar -
Chis-Ster I.& Ferguson N. . 2007 Transmission parameters of the 2001 foot and mouth epidemic in Great Britain. PLoS One. 2, e502 10.1371/journal.pone.0000502. Crossref, PubMed, ISI, Google Scholar -
Cowan F. M., French R.& Johnson A. M. . 1996 The role and effectiveness of partner notification in STD control: a review. Genitourin. Med. 72, 247–252. PubMed, Google Scholar -
Defra Veterinary Surveillance 2006. Full profile for foot and mouth disease. Electronic. See http://www.defra.gov.uk/animal/diseases/vetsurveillance/profiles/fmd-fullprofile.pdf. Google Scholar
-
Donnelly C. A., 2003 Epidemiological determinants of spread of causal agent of severe acute respiratory syndrome in Hong Kong. The Lancet. 361, 1761–1766.doi:10.1016/S0140-6736(03)13410-1. Crossref, PubMed, ISI, Google Scholar -
Eames K. T. D.& Keeling M. J. . 2003 Contact tracing and disease control. Proc. R. Soc. B. 270, 2565–2571.doi:10.1098/rspb.2003.2554. Link, ISI, Google Scholar -
Ferguson N. M., Donnelly C.& Anderson R. . 2001a Transmission intensity and impact of control policies on the foot and mouth epidemic in Great Britain. Nature. 413, 542–548.doi:10.1038/35097116. Crossref, PubMed, ISI, Google Scholar -
Ferguson N. M., Donnelly C. A.& Anderson R. M. . 2001b The foot-and-mouth epidemic in Great Britain: pattern of spread and impact of interventions. Science. 292, 1155–1161.doi:10.1126/science.1061020. Crossref, PubMed, ISI, Google Scholar -
Haydon D. T., Kao R. R.& Kitching R. P. . 2004 The UK foot-and-mouth disease outbreak—the aftermath. Nat. Rev. Microbiol. 2, 675–681.doi:10.1038/nrmicro960. Crossref, PubMed, ISI, Google Scholar -
Howard S. C.& Donnelly C. A. . 2000 The importance of immediate destruction in epidemics of foot and mouth disease. Res. Vet. Sci. 69, 189–196.doi:10.1053/rvsc.2000.0415. Crossref, PubMed, ISI, Google Scholar -
Jewell C. P. . 2008 Real-time inference and risk-predition for notifiable diseases of animals. PhD thesis, University of Warwick. Google Scholar -
Jewell C. P., Kypraios T., Roberts G. O.& Christley R. In press A novel approach to real-time risk-prediction for emerging infectious diseases: a case study in Avian Influenza H5N1. Prev. Vet. Med. Google Scholar -
Kao R. R. . 2003 The impact of local heterogeneity on alternative control strategies for foot-and-mouth disease. Proc. R. Soc. B. 270, 2557–2564.doi:10.1098/rspb.2003.2546. Link, ISI, Google Scholar -
Keeling M. J., 2001 Dynamics of the 2001 UK foot and mouth epidemic: stochastic dispersal in a heterogeneous landscape. Science. 294, 813–818.doi:10.1126/science.1065973. Crossref, PubMed, ISI, Google Scholar -
Kiss I. Z., Green D. M.& Kao R. R. . 2005 Disease contact tracing in random and clustered networks. Proc. R. Soc. B. 272, 1407 doi:10.1098/rspb.2005.3092. Link, ISI, Google Scholar -
Kontoghiorghes E. J. . 2006 Handbook of parallel computing and statistics Boca Raton, FL:Chapman and Hall. Google Scholar -
Kypraios T. . 2007 Efficient bayesian inference for partially observed stochastic epidemics and a new class of semi-parametric time series models. PhD. thesis, Department of Mathematics and Statistics, Lancaster University, Lancaster. Google Scholar -
Morens D. M., Folkers G. K.& Fauci A. S. . 2004 The challenge of emerging and re-emerging infectious diseases. Nature. 430, 242 doi:10.1038/nature02759. Crossref, PubMed, ISI, Google Scholar -
Neal P. J.& Roberts G. O. . 2004 Statistical inference and model selection for the 1861 Hagelloch measles epidemic. Biostatistics. 5, 249–261.doi:10.1093/biostatistics/5.2.249. Crossref, PubMed, ISI, Google Scholar -
O'Neill P. D.& Roberts G. O. . 1999 Bayesian inference for partially observed stochastic epidemics. J. R. Stat. Soc. Ser. A. 162, 121–129.doi:10.1111/1467-985X.00125. Crossref, ISI, Google Scholar -
Riley S.& Ferguson N. M. . 2006 From the cover: smallpox transmission and control: spatial dynamics in Great Britain. Proc. Natl Acad. Sci. USA. 103, 12 637–12 642.doi:10.1073/pnas.0510873103. Crossref, ISI, Google Scholar -
Robinson S. E.& Christley R. M. . 2006 Identifying temporal variation in reported births, deaths and movements of cattle in britain. BMC Vet. Res. 2, 11 doi:10.1186/1746-6148-2-11. Crossref, PubMed, Google Scholar -
Ryan E., 2008 Clinical and laboratory investigations of the outbreaks of foot-and-mouth disease in southern England in 2007. Vet. Rec. 163, 139–147. Crossref, PubMed, ISI, Google Scholar -
Savill N. J., Shaw D. J., Deardon R., Tildesley M. J., Keeling M. J., Woolhouse M. E., Brooks S. P.& Grenfell B. T. . 2006 Topographic determinants of foot and mouth disease transmission in the UK 2001 epidemic. BMC Vet. Res. 2, 3 doi:10.1186/1746-6148-2-3. Crossref, PubMed, Google Scholar -
The Royal Society Inquiry into infectious diseases in livestock, Tech. rep. 2002 London, UK:The Stationary Office. Google Scholar
-
Woolhouse M.& Donaldson A. . 2001 Managing foot-and-mouth. Nature. 410, 515–516.doi:10.1038/35069250. Crossref, PubMed, ISI, Google Scholar