NEW PRINCIPLES IN THE CONTROL OF PORCINE RESPIRATORY-DISEASES

The author has dealt with the program of the Swiss Pig Health Service (SGD) on the eradication of porcine respiratory diseases. The former g oal was to eradicate enzootic pneumonia (EP), rhinitis atrophicans (RA ), leptospirosis, swine dysentery and ectoparasites. Actinobacillosis (APP) was added later on. Nor the originally expected diagnostic probl ems caused difficulties to carry out the aimed program but ''mysteriou s'' (mainly EP and APP) reinfections. Its cause could not be explained for a long time until finally GOODWIN (1985) postulated and STARK (19 91) confirmed by retrospective investigations that the infections coul d be traced back by air-born infections spreading for longer distances . A formula was developed for calculating the risk of re-infections. T he R>50 value means a considerable risk in the EP-reinfection. The sto ck eradication policy has been changed for the territorial eradication and the program was also extended to the fattening stocks. Because th e epizootiologic character of EP has been confirmed, the veterinary au thorities classified EP and APP as epizootiological diseases to be era dicated. Paragraph No, 247 of the modified regulation contains the mea sures to be launched by the cantons. Supporting role of EP vaccination s has been determined. On behalf of the territorial eradication progra m, computer simulation of a region of 100 km(2) including 17 communiti es has been done by the Geographic Information System (GIS). The eradi cation started in two regions (Bern and Lucerne) in 1996. Data of thes e two regions and time-schedule of the planned eradication program hav e been detailed. Comprehensive evaluation of the results will be done in two doctoral theses in the near future.