The eradication of Aujeszky's disease in the United States

Abstract - The eradication of Aujeszky's Disease (AD) in the United States officially commenced in 1989. The program is designed so that each State progresses through 5 Stages. Stage I is the beginning or organizational stage. All State programs were functioning by 1991. Stage II is for functioning programs with greater than 1% of its herds infected; Stage III is for States with less than 1% of its herds being infected; Stage IV has no infected herds. States must remain in Stage IV for 1 year prior to applying for Stage V free status. In June of 1999 the United States had 32 States with Stage V (free) status and 8 States in Stage IV. Over 20 000 herds have been released from quarantine throughout this program. Approximately 700 herds remain quarantined June 1, 1999. All infected herds are on a mandatory test and removal of all positive testing breeding animals or a total herd depopulation/repopulation program beginning in January 1999. The goal is to have eradicated AD from all existing infected herds during 1999 and in the year 2000 to finalize eradication in any newly infected herds. Prior to the accelerated program that was initiated in 1999, the program in the United States progressed in a variety of ways that were specifically designed to fit the needs of each individual infected herd. Some plans were very simple and only entailed a test and removal of a few positive animals, but for the most part a total herd health plan was developed that could take from 2 to 3 years. These plans usually involved a 5-step program and improved bio-security of the herd. The 5 steps are: (1) Enhanced immunity (total vaccination) of the entire herd; (2) Development of a segregation system that includes early weaning; (3) Reduction of stress throughout the production system; (4) Monitoring of the herd to know when virus circulation has stopped; (5) Rotation of the positive breeding animals through test and removal or repopulation. By approaching Aujeszky's disease eradication from a swine farm management herd health program viewpoint the producer acceptance was greatly increased. Not only has the program been successful in eradicating Aujeszky's disease from nearly 20 000 swine farms, it has contributed to the overall management skills in high health status swine production in the United States. Many other swine diseases have been eliminated during this program. Producers have reported finishers reaching market weight in less time, with less medication, with less feed consumed, and with increased profits from their swine operations. It appears that Aujeszky's disease will be eradicated from the United States swine herds within the targeted time frame and the program will have made a significant contribution toward improved swine health and swine farm management in the United States.