Estimation of the Infection Window for the 2010/2011 Korean Foot-and-Mouth Disease Outbreak

Abstract

ObjectivesThis study aims to develop a method for calculating infection time lines for disease outbreaks on farms was developed using the 2010/2011 foot-and-mouth disease (FMD) epidemic in the Republic of Korea.MethodsData on farm demography, the detection date of FMD, the clinical history for the manifestation of lesions, the presence of antibodies against FMD virus (including antibodies against the structural and nonstructural proteins of serotype O), vaccination status (O1 Manisa strain), the number of reactors and information on the slaughter of infected animals were utilized in this method.ResultsBased on estimates of the most likely infection date, a cumulative detection probability that an infected farm would be identified on a specific day was determined. Peak infection was observed between late December and early January, but peak detection occurred in mid-January. The early detection probability was highest for pigs, followed by cattle (dairy, then beef) and small ruminants. Nearly 90% of the infected pig farms were detected by Day 11 post-infection while 13 days were required for detection for both dairy and beef cattle farms, and 21 days were necessary for small ruminant (goat and deer) farms. On average, 8.1 ± 3.1 days passed prior to detecting the presence of FMD virus on a farm. The interval between infection and detection of FMD was inversely associated with the intensity of farming.ConclusionThe results of our study emphasize the importance of intensive clinical inspection, which is the quickest method of detecting FMD infection and minimizing the damage caused by an epidemic.

Epidemiology and Investigation of Foot‐and‐Mouth Disease (FMD) in the Republic of Korea

“…As far as concerned to the detection delay, that was time passed prior to the detection of FMD infection on a farm (average ± standard deviation), was 8.1 ± 3.1 days. The detection delays were shortest for pig farms (7.1 ± 2.5 days) and longest for deer farms where a large variation was also observed (14.4 ± 8.1 days) [13].…”

Managing complexity: Simplifying assumptions of foot-and-mouth disease models for swine

“…Yoon et al. () estimated that, during the 2010/2011 FMD epidemics in the Republic of Korea, almost 90% of the infected pig farms were detected at about 11 days after infection. These findings are consistent with our study, which estimated that the mean time to detection based on clinical signs was approximately 11–12 days.…”

“…Although it is difficult to precisely measure the time from infection to detection within an infected farm during field outbreak investigations, the majority of recent FMD outbreaks have estimated the time from introduction to identification of the index case to be less than 25 days (McLaws & Ribble, 2007). Yoon et al (2013) estimated that, during the 2010/2011 FMD epidemics in the Republic of Korea, almost 90% of the infected pig farms were detected at about 11 days after infection. These findings are consistent with our study, which estimated that the mean time to detection based on clinical signs was approximately 11-12 days.…”

A Meta-Population Model of Potential Foot-and-Mouth Disease Transmission, Clinical Manifestation, and Detection Within U.S. Beef Feedlots

“…The outbreak was detected on day 4-12 since introduction of FMD latent cattle on the feedlot, if it was detected at 3% of clinical FMD cattle in the index home-pen ( Table 2). The time to FMD detection in cattle herds was estimated to be 21 days during the UK 2001 epidemic (42) and 13 days during the 2010/2011 Korean epidemic (73). McLaws and Ribble (74) reviewed the time to detection for FMD outbreaks in livestock in non-endemic areas during 1992 to 2003; it varied from 7 to 24 days and reasons for a delayed detection included misdiagnosis of the disease, mild clinical signs (in small ruminants), delayed laboratory confirmation, and deliberate underreporting by the affected farmers.…”