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ON “TICK PARALYSIS” IN SHEEP AND MAN 
FOLLOWING BITES OF DERMACENTOR 
VENUSTUS. 
' WITH NOTES ON THE BIOLOGY OF THE TICK. 
By SEYMOUR HADWEN, D.V.Sci., 
Pathologist to the Dominion Department of Agriculture, 
Expenmental Farm, Agassiz, B.C., Canada. 
(With Plates XXI and XXII.) 
History of the disease. 
For the past three years, 1910 to 1913, complaints have been 
received from a sheep farmer living near Keremeos, British Colombia, 
about a form of paralysis affecting his sheep and occurring annually fron) 
late February to early April. 
The history of the disease is as follows : 
In the autumn of 1910 he imported 900 sheep from Montana; all 
went well until the middle of March, 1911, when his sheep began to 
show symptoms of paralysis. During March and up to April 7 he lost 
46 old sheep. 
In 1912, from March 1 to 15, 34 yearling sheep were ill, but no old 
sheep; 10 head died. Later in the year (May, June and July), many 
more were affected—about 300 in all—and 80 died, but it is impossible 
to tell exactly what ailed them. Veterinary-Inspector Germyn, however, 
saw some of the diseased sheep and reported that they were suffering 
from a form of paralysis. 
In 1913, from March 25 to April 5, five yearlings were paralysed, but 
none died. 
Acting under instructions from my Department, I visited this 
district in April. I was unfortunate in not seeing any recent cases, but 
19—2 
