Emergency disease planning and preparedness

Abstract

For a number of years, Australian veterinary authorities have believed that the most likely point of entry into Australia for emergency animal diseases such as foot and mouth disease (FMD) is through pigs. This belief is based on the fact that pigs are the only omnivorous, FMD-susceptible species maintained domestically and thus the only species where swill feeding may potentially occur, despite it being illegal in all Australian jurisdictions. Further, the Australian commercial pig industry is based on high levels of management and good biosecurity practices, so (illegal) swill feeding is considered more likely to occur in smaller piggeries where behaviour may be opportunistic rather than in line with best biosecurity practice.1 Previous studies published in this journal2 have shown a lack of knowledge surrounding the practices and even the location of smallholder pig farmers in Australia. Information on the movement patterns and marketing practices within the pig industry has also been lacking and therefore the ability of governments and industry to plan for disease outbreaks has been compromised. In this month's edition of the Journal, East et al. describe the structure and dynamics of the Australian pig industry.3 Information on the frequency, size and source/destination of pig movements within Australia is presented. This information will be used to facilitate risk assessments and disease outbreak modelling studies to assist emergency disease planning and preparedness. The study design of interviewing 370 producers is a significant advance over the previous study in 2007 commissioned by the same authors that was based predominantly on expert opinion.4 A proportion of the interviewees demonstrated at least a basic knowledge of biosecurity, with 45% not introducing any pigs onto their farm and 12% maintaining closed herds. The pig industry was found to fall broadly into two categories: larger farms that were vertically integrated, purchased semen to introduce new genetic material and did not market through saleyards and smaller producers that regularly used saleyards to both purchase and sell pigs. This study compliments that written by Schembri et al,5 published recently, who examined the demographics and practices of pig farmers trading at saleyards in eastern Australia. Although the two studies have different study populations, different aims and were conducted 6 years apart, where the results overlap the findings are consistent. Both studies found that saleyards are used predominantly by smallholders whereas larger producers sell predominantly to abattoirs. In addition, the majority of producers use the saleyard that is geographically closest, although a small percentage will travel several hundred kilometres to buy or sell pigs. Both studies achieved a high response rate to their questionnaires and interviews, demonstrating the overall high level of support for research within the pig industry. Although less than 2% of pigs in Australia are now sold through saleyards, the opportunity for large numbers of pigs and other species to mix and subsequently disperse to multiple locations provides a major potential pathway for the rapid dissemination of disease across Australia. The ability to trace movements of animals is therefore critical and the introduction of the PigPass system that allows for tracing of pigs moving between properties with different Property Identification Codes to an abattoir or a saleyard is a significant advance in traceability. However, the current system is paper-based and not centralised, limitations that make rapid tracing more difficult. A requirement for all pigs passing through saleyards to be branded and tagged appropriately and the use of saleyard tags (such as in the National Livestock Identification System) and brands for unmarked animals would facilitate tracing in the event of an emergency disease event and address the incidence of non-compliance with PigPass registration and branding reported previously by Holyoake and Hernandez-Jover.6 These studies characterising the Australian pig industry increase our understanding of the industry and improve our ability to prevent or control disease within the industry, outcomes that will enhance both the productivity and the profitability of this industry.