608 Epizootic Cerebio-spinal Meningitis. 



tent. Sometimes the}- are very extensive and cause severe 

 losses and at other times there are only sporadic cases. The 

 outbreaks tend to be more severe in years when the rainfall is 

 heavy. It is observed, as a rule, on cultivated land only. In 

 the majority of cases the disease occurs in aifectod districts 

 only on certain farms or on certain parts of a farm, and there 

 may be only one animal affected in a stable, while in other cases 

 there may be a large number diseased and the death rate may be 

 high. The severity of the disease appears to vary with the sea- 

 sons. As a rule the first serious outbreaks occur in January 

 and February. The maximum is reached in May or June and 

 from this time they gradually decline, and in the last quarter of 

 the year there may be either sporadic cases only or the disease 

 may disappear entirely. This cyclical occurrence, which is par- 

 ticularly noticeable in affected districts in Germany, is prob- 

 ably dependent upon the heavy rainfall and the warmth of the 

 earth during the second and third quarters ; these factors in all 

 probability favoring the development of the cause of the dis- 

 ease (Liebener). The sporadic cases which apparently occur 

 everywhere are probably an independent type of meningitis 

 (Christiani). 



In Germauy the disease is especially eommon in Saxony, Thiiringen and 

 Wiirtemburg. In Saxony the following districts are chiefly affected: Borna, 

 Grimnia, Zwickau, Planen, Auerbach, Chemnitz, Leipaig, Bautzen, Glauehau and 

 Eochlitz. In 1896 there were 1,198 horses attacked, and in the years 1903-1908 

 there were 439, 590, 264, 213, 1,095, and 508. In 1903 compensation amounting 

 to $140,536 was paid for 439 horses, and during the period 1904-1908 the com- 

 pensation for 2,903 horses amounted to $346,496. The disease has been known 

 in the Province of Saxony for the last thirty years, but it was in 1896 that it first 

 became widely disseminated. The districts principally involved were Merseburg 

 and Erfurt, Deiitzsch, Eckartsberga, Querfurt, Saalkreis, Merseburg, Weissenfels, 

 Ziegenriick, Weissensee, Langensalza. The following are the numbers of cases 

 during the period 1897-1908: 86, 137, 499, 317, 162, 81, 109, 224, 52, 62, 492, and 

 127. In the years 1901-1906 the disease was reported in Schwarzburg-Rudolstadt, 

 and isolated cases occurred in Saxe-Coburg-Gotha and Magdelnirg. 



The disease was observed in Hungary in 1S80-18S2 and again in 1897 and 

 1898 in horses in the district of Zemplem. About 200 animals were affected. 

 Fresh outbreaks have been rejjorted since that time. 



Two great outbreaks have been reported in Belgium. 



Cases have occurred in horses in Great Britain and Eussia, more than 200 

 horses dying in the Don Province in 1902. 



In North America, New York, Pennsylvania, New Jersey, Minnesota, On- 

 tario, and Illinois appear to be the most seriously affected. About 4,000 horses 

 and mules were destroyed in the valleys of the Brazos and Colorado rivers. 



Etiology. Epizootic cerebro-spinal meningitis is due to an 

 infection. 



In the subarachnoidal fluid of a horse affected with the socalled 

 Borna disease, Siedamgrotzky & Schlegel found a micrococcus and more 

 rarely a diplococcus measuring about 0.6 /x. On the surface of gelatin 

 this organism formed dirty white, sharply circumscribed colonies about 

 the size of linseed. These colonies showed a characteristic dense-look- 

 ing point at the center. In broth there was diffuse turbidity and a 

 large amount of flocculent deposit. Intravenous inoculation with cul- 

 tures into horses in one case produced no effect ; in a second, there were 



