The AD eradication plan was initialed in 1989 at the federal level wit
h a 10-year completion date target of the year 2000. Most states requi
red new legislation to support the program. The plan has been a joint
effort with federal agencies contributing funds and rules; producer gr
oups, producers and national groups as Livestock Conservation Inc., an
d US Animal Health Association state/federal extension staff, and indu
stry. A National Advisory Committee was formed to establish program pr
iorities, monitor progress, assist in program reviews in states and to
monitor research and field evaluation. In general states enter the pr
ogram at various levels and move through ''stages'' as they are able.
Currently stales are in various stages and some have split status (Tab
le). The status affects animal movement. Funding for the program has c
ome from federal and stare governments and producers. Federal funds ha
ve been distributed on the basis of need and program success. The five
s stages in the plan are: I. Preparation, II. Control, III. Mandatory
Herd Clean-Up, IV, Surveillance, V. Free Status, Herds are classified
into the following categories ''Qualified Negative Herd'', ''Qualified
Negative Vaccinated Herd'', ''Monitored Feeder Pigs''. Herd clean up
plans are variable by stale or area and are regulated by the state PR
committee and regulatory officials. One of four clean-up plans or vari
ations are selected by veterinarian and herd owner: 1. Depopulation/Re
population, 2. Test and Removal, 3. Off-spring Segregation, 4. Vaccina
tion/Segregation. The program is based on an Official Statistical Test
(90% detection if 10% of animals infected) (test all below 10 herds,
test 30% - or min. 30 - above 36 heads). Random surveillance and monit
oring is done al slaughterhouses or al first point of collection, with
10% of area population or breeding herds surveyed annually. Gene dele
ted vaccines are essential elements of eradication. They were first us
ed in the 1980's and limitations placed on such products in the 1990's
. Program standards allow any deletion but require the GI deletion. Th
e progress of eradication and stages of various states of April 1995-J
anuary 1. 1997 are demonstrated on Figures 1 and 2. The sources of the
new infection in herds are seen on the Figure 3.