Abstract
In 1968, 100 Suffolk sheep were imported from Australia into the Rumoi district of Hokkaido. One of them died soon after arrival. Autopsy revealed some of its bronchioli harboring white nematodes, which were identified as Dictyocaulus filaria (RUDOLPHI, 1809). Then a number of sheep of this flock were found to cough and run at the nose. Parasitological examination was conducted on this flock by the separation method with centrifugation tubes. It demonstrated the presence of larvae of stage I in 49.3 per cent of the 99 sheep.
The flock was treated with tetramisole in a dose of 15mg/kg. Two weeks later, larvae were detected from no sheep of the flock. No death occurred to the flock over a period of observation of 5 months, at the end of which no larvae were detected from any sheep.
