A Parallel Traceforward-Traceback Simulation at Large Scale

In April 2006 the USDA-APHIS released a voluntary animal identification and traceability framework collectively known as the National Animal Identification System (NAIS). The basic goal of the NAIS program is to associate a unique identifier (animal ID) to every element of commercial livestock in the United States and to maintain a dynamic, real time database of livestock movement. In the event of an infectious disease outbreak (e.g. Bovine Spongiform Encephalopathy (BSE), also known as Mad Cow Disease) such a database could be rapidly searched in order to trace the possible spread of the infection to both individual animals as well as entire heards and livestock premises. It is widely believed that the implementation of a mandatory animal traceabitity system is vital to safegaurding the U.S. food supply, protecting human health, and mitigating economic threat. To date much of the effort surrounding the development of the NAIS has encompassed the identification of livestock production and handling premises and the identification of individuals or heards of animals, however, little effort has been directed towards the accomplishment of the ultimate goal of the program which is an animal traceback in 48 hours. Recent epidemiological investigations following the 2003 announcement of the first case of BSE detected in the United States have highlighted the lack of traceability currently available in the United States. The current length of such an investigation is weeks or months as opposed to the desired hours or days. Further complicating the issue are incomplete and or missing records. In the case of BSE the transmission and development of the disease is extremely slow (years), thus the length of these ivestigations was immaterial. Had this been a more infectious agent (e.g. Avian influenza) the length of time required to trace, identify and contain cohort animals and premises would have resulted in essentially 100% quarantine of U.S. animal production, process and animal product distribution. Such