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Surveillance and the Early Detection of Foot and Mouth Disease. Melissa McLaws DVM – PhD Candidate, Dept of Population Medicine, University of Guelph Carl Ribble DVM, MSc, PhD – Advisor Craig Stephen DVM, PhD – Member of advisory committee
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Surveillance and the Early Detection of Foot and Mouth Disease • Melissa McLaws DVM – PhD Candidate, Dept of Population Medicine, University of Guelph • Carl Ribble DVM, MSc, PhD – Advisor • Craig Stephen DVM, PhD – Member of advisory committee • Bruce McNab DVM, PhD – Member of advisory committee
Foot and Mouth Disease (FMD) • Highly contagious disease of cloven-hoofed animals (including cattle, sheep, pigs) • Re-emerging disease? • Large outbreaks of disease have recently occurred in areas that had been free of disease for a long time (UK, Taiwan) • High profile • Concern as agent of bio-terrorism
FMD: Epidemiology • Infection by inhalation or ingestion of the virus • Spread on farm – direct contact, mechanical • Spread between farms – animal movements, fomites (people,vehicles, wildlife) • Wind-borne transmission (spread esp. by pigs, cattle esp. susceptible)
FMD: Clinical Signs • Fever, depression, milk-drop • Lameness • Salivation • Vesicles in mouth, coronary band, teats • Ruptured vesicles…+/- secondary infection • Sudden death – young animals • Species differences (maybe subtle and transient in sheep/goats)
FMD: Diagnosis • Currently, case identification is dependent on recognition of clinical signs (rather than screening with a lab test) • Non-endemic situation – passive surveillance • Epidemic (and endemic) situation- active and passive surveillance
Non-Endemic Situation HIGH RISK PERIOD Disease circulating in endemic area Introduction to non-endemic area Detection of disease in non-endemic area Control Procedures Time
Non-endemic Situation • Identified outbreaks of FMD in countries where the disease is not endemic from 1992-2002 • Literature review • Little information about how the outbreaks were found • Identify and describe factors that contributed to the final epidemic size
Taiwan 1997 UK 2001; Uruguay 2001 Yugoslavia 1996; Greece 1994 # Infected Premises Italy 1993 Greece 1996 Netherlands 2001; Brazil 2000 S. Korea 2000 & 2002; Greece 2000 Japan 2000; S. Africa 2000; Swaziland 2000; Botswana 2002 & 2003; France 2001; Ireland 2001; Uruguay 2000; Argentina 2000; Bulgaria 1993
Discussion • Most incursions of FMD virus lead to a relatively small outbreak, but on 3 occasions there was a big one: WHY? • Late detection? • Animal movement? • Virulent strain? • Animal density?
Time since previous outbreak Education Veterinary Infrastructure Awareness Time from Infection to Detection Livestock demographics (density, type, husbandry) Unrestricted Animal Movement Level of Viral Shedding EPIDEMIC SIZE Species Affected Control - Methods and Effectiveness Viral Strain