A Comparative Assessment of the Risks of Introduction and Spread of Foot-and-Mouth Disease among Different Pig Sectors in Australia.

Marta Hernández-Jover,Patricia K Holyoake,Peter Anthony Julian Martin,Jenny-Ann L M L Toribio,Nicole Schembri

doi:10.3389/fvets.2016.00085

Marta Hernández-Jover, Patricia K Holyoake + Show 3 more

Open Access

https://doi.org/10.3389/fvets.2016.00085

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Abstract

Small-scale pig producers are believed to pose higher biosecurity risks for the introduction and spread of exotic diseases than commercial pig producers. However, the magnitude of these risks is poorly understood. This study is a comparative assessment of the risk of introduction and spread of foot-and-mouth disease (FMD) through different sectors of the pig industry: (1) large-scale pig producers; (2) small-scale producers (<100 sows) selling at saleyards and abattoirs; and (3) small-scale producers selling through informal means. An exposure and consequence assessments were conducted using the World Organization for Animal Health methodology for risk analysis, assuming FMD virus was introduced into Australia through illegal importation of infected meat. A quantitative assessment, using scenario trees and Monte Carlo stochastic simulation, was used to calculate the probabilities of exposure and spread. Input data for these assessments were obtained from a series of data gathering exercises among pig producers, industry statistics, and literature. Findings of this study suggest there is an Extremely low probability of exposure (8.69 × 10−6 to 3.81 × 10−5) for the three sectors of the pig industry, with exposure through direct swill feeding being 10–100 times more likely to occur than through contact with infected feral pigs. Spread of FMD from the index farm is most likely to occur through movement of contaminated fomites, pigs, and ruminants. The virus is more likely to spread from small-scale piggeries selling at saleyards and abattoirs than from other piggeries. The most influential factors on the spread of FMD from the index farm is the ability of the farmer to detect FMD, the probability of FMD spread through contaminated fomites and the presence of ruminants on the farm. Although small-scale producers selling informally move animals less frequently and do not use external staff, movement of pigs to non-commercial pathways could jeopardize animal traceability in the event of a disease outbreak. This study suggests that producers’ awareness on and engagement with legislative and industry requirements in relation to biosecurity and emergency animal disease management needs to be improved. Results from this study could be used by decision-makers to prioritize resource allocation for improving animal biosecurity in the pig industry.

Highlights

Small landholders are commonly thought to pose biosecurity risks to mainstream livestock production, the magnitude and significance of these risks have not been previously evaluated
Large/small scale Infected animals moving to another piggery where the infection is detected and reported: this scenario represents limited spread to a local pig community, depending on movement of other animals from the index farm until infection is detected at the second piggery, time of the detection at the second piggery, the presence of ruminants at this piggery and the movement of animals from this piggery before detection b
These results stress the importance of maintaining appropriate biosecurity practices to minimize the spread of foot-and-mouth disease (FMD) through fomites, such as pig transport and visitor vehicles, clothes and equipment

Summary

Introduction

Small landholders are commonly thought to pose biosecurity risks to mainstream livestock production, the magnitude and significance of these risks have not been previously evaluated. Illegal introduction of meat products by incoming passengers from infected countries is the highest risk source of entry of FMD into Australia [13,14,15]. Previous studies have investigated the risk of introduction of and subsequent exposure to emergency animal diseases, such as FMD, CSF, and ASF, from the illegal importation of meat products [20, 22, 23]. Hartnett et al [22] quantified the risk of FMD introduction and exposure in Great Britain and Costard et al [20] assessed the risk of ASF introduction and exposure in Europe In both studies, poor biosecurity practices, especially among backyard producers and the presence of feral pigs were identified as highly influential on the probability of exposure of domestic pigs to these viruses

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