Risk of foot‐and‐mouth disease associated with proximity in space and time to infected premises and the implications for control policy during the 2001 epidemic in Cumbria

Taylor, Nick; Honhold, N.; Paterson, A. D.; Mansley, L. M.

doi:10.1136/vr.154.20.617

Cited by 38 publications

(29 citation statements)

References 11 publications

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“…Thus, three km of spatial distance was selected subjectively and used as the only analytical approach for geographical distance, while a temporal distance of 3 mo was used as the most important, but not the only, temporal cutpoint. This spatial cutpoint was in concordance with how local spread was defined in a field during the 2001 outbreak of foot-and-mouth disease in the UK [14]. Our assumption was that the causative agent of PCVAD from the initially infected premises would not be more contagious to neighboring farms than the foot-and-mouth disease virus.…”

Section: Discussionsupporting

confidence: 70%

Spread of porcine circovirus associated disease (PCVAD) in Ontario (Canada) swine herds: Part II. Matched case-control study

et al. 2010

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BackgroundThe emergence of porcine circovirus associated disease (PCVAD) was associated with high mortality in swine populations worldwide. Studies performed in different regions identified spatial, temporal, and spatio-temporal trends as factors contributing to patterns of the disease spread. Patterns consistent with spatial trend and spatio-temporal clustering were already identified in this dataset. On the basis of these results, we have further investigated the nature of local spread in this report. The primary objective of this study was to evaluate risk factors for incidence cases of reported PCVAD.ResultsA time-matched case-control study was used as a study design approach, and conditional logistic regression as the analytical method. The main exposure of interest was local spread, which was defined as an unidentified mechanism of PCVAD spread between premises located within 3 kilometers of the Euclidean distance. Various modifications of variables indicative of local spread were also evaluated. The dataset contained 278 swine herds from Ontario originally sampled either from diagnostic laboratory submissions or directly from the target population. A PCVAD case was defined on the basis of the producer's recall. Existence of apparent local spread over the entire study period was confirmed (OR = 2.26, 95% CI: 1.06, 4.83), and was further identified to be time-varying in nature - herds experiencing outbreaks in the later part of the epidemic were more likely than control herds to be exposed to neighboring herds experiencing recent PCVAD outbreaks. More importantly, the pattern of local spread was driven by concurrent occurrence of PCVAD on premises under the same ownership (OREXACTwithin ownership = 25.6, 95% CI: 3.4, +inf; OREXACToutside ownership = 1.3, 95% CI: 0.45, 3.3). Other significant factors included PRRSv status of a herd (OREXACT = 1.9, 95% CI: 1.0, 3.9), after adjusting for geographical location by including the binary effect of the easting coordinate (Easting > 600 km = 1; OREXACT = 1.8, 95% CI: 0.5, 5.6).ConclusionsThese results preclude any conclusion regarding the existence of a mechanism of local spread through airborne transmission or indirectly through contaminated fomites or vectors, as simultaneous emergence of PCVAD could also be a result of concurrent change in contributing factors due to other mechanisms within ownerships.

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Section: Discussionsupporting

confidence: 70%

Spread of porcine circovirus associated disease (PCVAD) in Ontario (Canada) swine herds: Part II. Matched case-control study

et al. 2010

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“…Moreover, flocks that were considered at risk of infection based on the proximity (<1 km) to, or dangerous contacts with IFs, were inspected and laboratory analysis was carried out according to EU standards (CEC, 1992) The hypothesized infectious period of each IF was modelled as a Temporal Risk Window (TRW). The TRW can be defined as the time period during which clinical signs could be identified in any other farm infected by transmission from the IF (Taylor et al, 2004). The TRW was calculated for each IF as following (Mannelli et al, 2006):…”

Section: Data Sourcesmentioning

confidence: 99%

Evaluation of the risk of neighbourhood infection of H7N1 Highly Pathogenic Avian Influenza in Italy using Q statistic

Mulatti

Kitron

Jacquez

et al. 2010

Preventive Veterinary Medicine

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“…In the case of FMD, the main risk factor contributing to transmission of disease has been shown to be proximity to previously infected farms [14]–[16] and it therefore seems that a precise knowledge of farm locations may be vital to making epidemiological predictions.…”

Section: Introductionmentioning

confidence: 99%

Disease Prevention versus Data Privacy: Using Landcover Maps to Inform Spatial Epidemic Models

Tildesley

Ryan

2012

PLoS Comput Biol

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The availability of epidemiological data in the early stages of an outbreak of an infectious disease is vital for modelers to make accurate predictions regarding the likely spread of disease and preferred intervention strategies. However, in some countries, the necessary demographic data are only available at an aggregate scale. We investigated the ability of models of livestock infectious diseases to predict epidemic spread and obtain optimal control policies in the event of imperfect, aggregated data. Taking a geographic information approach, we used land cover data to predict UK farm locations and investigated the influence of using these synthetic location data sets upon epidemiological predictions in the event of an outbreak of foot-and-mouth disease. When broadly classified land cover data were used to create synthetic farm locations, model predictions deviated significantly from those simulated on true data. However, when more resolved subclass land use data were used, moderate to highly accurate predictions of epidemic size, duration and optimal vaccination and ring culling strategies were obtained. This suggests that a geographic information approach may be useful where individual farm-level data are not available, to allow predictive analyses to be carried out regarding the likely spread of disease. This method can also be used for contingency planning in collaboration with policy makers to determine preferred control strategies in the event of a future outbreak of infectious disease in livestock.

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Risk of foot‐and‐mouth disease associated with proximity in space and time to infected premises and the implications for control policy during the 2001 epidemic in Cumbria

Cited by 38 publications

References 11 publications

Spread of porcine circovirus associated disease (PCVAD) in Ontario (Canada) swine herds: Part II. Matched case-control study

Spread of porcine circovirus associated disease (PCVAD) in Ontario (Canada) swine herds: Part II. Matched case-control study

Evaluation of the risk of neighbourhood infection of H7N1 Highly Pathogenic Avian Influenza in Italy using Q statistic

Disease Prevention versus Data Privacy: Using Landcover Maps to Inform Spatial Epidemic Models

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