^62 Veterinary Medicine. 



Definition. An ectogenous, infective disease of solipeds in 

 South Africa, characterized by intense vascular congestions, de- 

 structive changes in the blood and the profuse exudation of liquor 

 sanguinis into the tissues of the affected parts. 



Geographical Distribution. The affection is not known out of 

 South Africa, where it has been observed since 1780. It appears 

 yearly in certain areas in the Transvaal, Orange River Colony, 

 Natal, and adjacent States, but only in certain years in Cape 

 Colony and especially in its southern portion. In some years 

 it makes wide extensions so that it has appeared to become epi- 

 zootic instead of enzootic. The habitual enzootic prevalence is 

 in the areas that are relatively lower, damper and richer than the 

 surrounding country, where the vegetation is luxuriant and the 

 surface of the ground moist. Thus it is a disease of low meadows, 

 basins, river bottoms, drying marshes or ponds, and the Boers 

 have been in the habit of protecting their horses by sending them 

 to high, dry tablelands, from the first appearance of the disease 

 until the first frost. Yet elevation in itself is no protection, thus 

 Johannisburg, 6000 feet above_ the sea, is habitually ravaged and 

 Rhodesia loses 90 per cent, annually. A humid atmosphere, 

 mist, or rain with a high temperature are directly connected with 

 the outbreaks. 



Animals Susceptible. Horses take the disease in its most fatal 

 form. Mules suffer like horses, while in asses and guaggas the 

 malady is relatively somewhat more benign, and the virus after 

 having passed through the ass, has lost part of its potency. It 

 does not attack cattle nor goats. (Theiler. See Heart water. ) 



Causes. The affection has been traced to the green forage, 

 grown in damp, hot seasons on the rich moist bottom lands, in 

 basins, gullies, etc., and which has been consumed while damp 

 with night dews or fog. Few suffer that are only turned out to 

 pasture after the sun has dried up the dew, and that are shut in 

 the stable or kraal before sunset. Coley who witnessed a loss of 

 60 per cent of the stabled horses at Eshowe, Zululand, found 

 that the deaths were among horses that had been allowed to eat 

 their fodder wet. The Guinea or Ubaaba grass and Indian corn 

 were cut at night and fed to the horses next day. The horses that 

 ate this wet from the bundles were attacked, while those that had 

 it only after it had been opened and dried in the sun escaped. 



