Infectious Abortion of Mares 479 



abortion was total as to foals, and four of the mares perished be- 

 cause of sequelae. Other similar instances might be related 

 without number and give a somewhat vivid impression of the 

 enormous losses which may be caused by this malady. 



The infectiousness of the disease is shown by clinical obser- 

 vation. In a large proportion of cases it is possible to trace the 

 beginning of an outbreak of abortion in a herd of mares to the 

 temporary or permanent indroduction of a mare from a herd in 

 which the malady already existed. A pregnant mare is bought 

 from an infected herd and placed in the stable or pasture with 

 pregnant mares, which, up to the time, were free from the 

 disease. Within a few days abortion sets in and nearly or all 

 the pregnant mares in the herd abort as a result. In other cases, 

 a neighbor has driven a pregnant mare, or one which has re- 

 cently aborted, from his own farm to that of his neighbor and has 

 placed it in close proximity to the pregnant mares or has tempora- 

 rily placed it in the stable, and even in the same stall where preg- 

 nant mares are later brought. Within a few days, these mares 

 in turn commenced to abort. Or, the owner of a number of 

 pregnant mares drives one of them to a neighbor's or to a public 

 stable where animals afflicted with the disease have been kept. 

 Returning home, this mare soon aborts. After an interval, other 

 abortions follow^ and finally destruction of the entire foal crop. 



Guillerey (Archiv fur Tierheilkunde, Vol. 29, page 37) gives 

 us some excellent data of the way in which an outbreak of 

 abortion in mares spread in his territory'. G. was called on 

 January 27, 1897 to remove the afterbirth from a six year-old 

 mare which had aborted at 10 months the previous evening. As 

 the mare was unable to expel the fetus without assistance, the 

 owner asked four neighbors to assist him. Three days later, in- 

 fectious abortion of a virulent character broke out in the stables 

 of each of these four friends. On the 4th of February, in the 

 same locality, two mares owned by P. aborted. Three days 

 previously P. had assisted a neighbor in a case of difficult labor 

 from abortion. In another case he records that a mare aborted, 

 and that neighbors who entered the stable conveyed the in- 

 fection to their own animals, which, in turn, aborted. Following 

 the entire outbreak, G. was able to trace the source of infection 

 with uniformity from stable to stable and from village to village. 



