THE INTRODUCTION AND SPREAD OF HOG CHOLERA IN THE 



UNITED STATES. 



The accompanying correspondence, relating to the history and 

 spread of hog cholera, covers a wide area of all the States and Territo- 

 ries of the United States. The letters are from statistical and other 

 correspondents of the Department, and give, perhaps, as reliable and 

 authentic a history of the appearance and spread of the disease in this 

 country as it will ever be possible to collect. More than a thousand 

 replies were received to the circular letter sent out by the Bureau of 

 Animal Industry, and many of them were so carefully prepared as 

 to be of much interest and value to those engaged in the breeding 

 and rearing of swine. Nearly all agree in stating that at one time 

 the swine industry was not subject to the periodical losses from epi- 

 zootics which now cause such discouraging losses. From the first 

 appearance of this class of diseases the outbreaks became more nu- 

 merous and more wide-spread, until nearly all parts of the country 

 are now subject to frequent invasions. 



The first outbreak of the disease supposed to be hog cholera that 

 is referred to occurred, in Ohio in 1833. It is reported from one 

 county in South Carolina in 1837, and from one in Georgia as hav- 

 ing existed in 1838. It existed in 1840 in one county in Alabama, 

 one of Florida, one of Illinois, and one of Indiana. In 1843 it is re- 

 ported from one county in North Carolina. In 1844 one county in 

 New York reports being affected. Its presence in 1845 is only men- 

 tioned by one correspondent from Kentucky. 



The thirteen years, from 1833 to 1845, inclusive, form a period in 

 which but ten outbreaks of swine disease, supposed by the writers 

 to have been hog cholera, were mentioned in these replies. It is 

 evident that during this period hogs were generally healthy 

 throughout the country, and that the losses from disease were not 

 sufficient to attract very much attention. The nature of the disease 

 referred to as existing so long ago may, of course, be questioned at 

 this day, and we have no means of deciding whether or not any par- 

 ticular outbreak was cholera or some non-contagious malady due 

 to local conditions. It is reasonable to conclude, "however, that the 

 correspondents are correct in their opinion in most cases, because, 

 since 1845, the outbreaks mentioned became more numerous year by 

 year until we find nearly the whole country involved. This rapid 

 increase of the number of affected sections would seem to indicate 

 that a contagious disease had been introduced and carried to widely 

 separated sections of the country, from which it extended until, with 

 a year favorable to its propagation, we find a sudden and alarming 

 increase,. 



Turning again to the number of outbreaks reported, we find, in 

 1846, that there were two in North Carolina, one in Georgia, one in 



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