Relationship of speed of slaughter on infected premises and intensity of culling of other premises to the rate of spread of the foot‐and‐mouth disease epidemic in Great Britain, 2001

Abstract

During the foot-and-mouth disease epidemic in the UK in 2001, two major control policies were the rapid identification of cases and the culling of animals on infected premises and on dangerous contact premises. Dangerous contact premises were divided into two groups, premises contiguous to an infected premises and non-contiguous premises. In England, the largest numbers of geographically clustered infected premises were in Cumbria, the South West (Somerset, Devon and Cornwall) and the Settle/Clitheroe area straddling the Yorkshire-Lancashire border. In each of these clusters, the rate of spread of the disease, the average time from the first lesion to slaughter on infected premises, and the intensity of culling of contiguous premises and non-contiguous premises were calculated for seven-day periods. Linear regression analysis was used to look for relationships between these factors and the rate of spread of the disease. The average time from the first lesion to slaughter had a statistically significant relationship in two of the three clusters and the intensity of culling of non-contiguous premises had a significant relationship in one. The intensity of culling of contiguous premises had no significant relationship in any of the three clusters.

A comparison of predictions made by three simulation models of foot-and-mouth disease

“…Although not included in some of the mathematical models used in the FMD epidemic in the United Kingdom in 2001 (Ferguson et al 2001;Keeling et al 2001), it was accepted that there was within-herd transmission of FMD (Hutber and Kitching 2000). Accordingly, it is likely that farm-level infectiousness would increase over time as the number of animals infected increased (Taylor 2003;Haydon et al 2004;Honhold et al 2004;Kitching et al 2006). Future comparisons should assess the impact of within-herd spread in more complex, realistic scenarios.…”

Epidemiological Characteristics of the 2002 Outbreak of Foot-and-Mouth Disease in The Republic of Korea

“…An estimate of the infection date (or window) is an important part of the broader epidemiological investigation, particularly with respect to determining potential modes of viral transmission. Although the incubation period of FMD under field conditions is highly variable and depends on several factors including the strain and dose of virus (Kitching and Alexandersen, 2002), it is generally considered to be about 5 days (range 1–11 days) in pigs based on experimental infection (Kitching, 1992; Kitching and Alexandersen, 2002; Honhold et al., 2004). In the 1997 Taiwan epidemic, however, the incubation period in pigs were very short, just 1–2 days (Yang et al., 1999), which supports the view that the incubation period tends to be shorter in natural as compared with experimental infection (Roth et al., 1994).…”

The ideal reporting interval for an epidemic to objectively interpret the epidemiological time course

“…The method suffers from wide uncertainty when there is only a small number of cases (e.g. during early and late stages of an epidemic), but our approach greatly improves previous similar intent (Honhold et al 2004) in that our method can yield a strictly interpretable quantity, R t , to understand the epidemiological pattern of spread.…”