nials, inc-ludiiiK wilcilife, submitted from all 

 parts of the United States are examined for 

 antibodies apainst at least 12 leptospiral sero- 

 types. This service is of particular value where 

 signs of leptospirosis are observed, but routine 

 testing with Lcptn?:pira pomona antigen yields 

 negative results. Where infection with the 

 less common serotypes is indicated locally 

 (Iowa), field investigations are performed in 

 an effort to isolate the causative agent. 



Enzootic abortion 



Record of the Decade. — The virus of en- 

 zootic abortion in ewes was first discovered in 

 Scotland in 1950. Since then it has also been 

 reported in several European countries. 



In the spring of 1958, the Montana Veteri- 

 nary Research Laboratory isolated and identi- 

 fied the virus in ewes in Montana. This was 

 the first report of the disease in this country. 

 It confirmed the belief that many of the hith- 



erto undiagnosed cases of abortion in sheep in 

 the United States may have been due to this 

 viru.s. Its similarity to the enzootic abortion 

 virus of Scotland was subsequently established 

 i)y a Scottish research group. Although exact 

 distribution and prevalence of the disea.se in 

 the United States were unknown, it was sus- 

 I)ected to be widespread. 



A Study of Incidence. — The Division en- 

 tered into an agreement with Montana State 

 College on January 2G, 1959 to study the preva- 

 lence of enzootic abortion in ewes in this coun- 

 try and to improve the antigen u.sed in the com- 

 plement-fixation test for the disease. 



The survey was initiated by soliciting sam- 

 ples from flocks in which ewes had aborted and 

 had a negative history as regards vibrio in- 

 fection. During the period January 25, 1959 

 to April 21, 19()(), the following results were 

 i-ejiorted by Montana Veterinary Research 

 Laboratory, Montana State College : 



Incidence of enzootic abortion reported during the period January 26, 1959-May 16, 1960 



State 



Arizona 



California 



Colorado 



Idaho 



Montana 



Nebraska 



North Dakota. 



Oregon 



South Dakota 



Tennessee 



Utah 



West Virginia. 



Wisconsin 



Wyoming 



Minnesota 



New Mexico.. 



New York 



Iowa 



Totals'. 

 Percent. 



Flocks 



Total 



1 

 6 

 1 

 22 

 18 

 2 

 4 

 2 

 1 

 2 

 5 

 1 

 1 

 9 

 1 

 1 

 1 

 1 



79 



Positive 





 1 

 

 18 

 7 

 

 

 1 

 

 1 

 4 

 

 

 3 

 

 

 

 



35 

 44.3 



Suspicious 



o 

 6.0 



Sheep 



Total 



38 

 61 



6 



1,416 



587 



26 



42 



11 



35 



19 



293 



1 

 15 

 86 



4 

 15 



7 



9 



:,67i 



Positive 





 1 

 

 152 

 78 

 

 



1 







1 



22 

 

 



16 

 

 

 

 



Suspicious 



271 

 10.7 





 2 







83 



24 







3 



1 











30 











15 



















158 

 5.8 



' Positive flocks were found in 7 of 18 States submitting samples. Suspicious flocks were found in 1 additional State. 



43 



