408 SURRA 



3,500,900, the white 14,500. In another, ill six weeks, the red blood 

 cells were 3,200,000, and the white were 13,900. The blood of a healthy 

 horse, taken as a comparison, gave red blood cells 6,900,000, white 

 9,800. There is also a slight diminution in the amount of hitmoglobin, 

 about 85 per cent. 



" After convalescence has been fully established, no parasite can be 

 found, the blood gradually assumes its normal constitution. 



"The parasite is not confined to the blood, as it can be demonstrated 

 in the serous effusions. 



" It is quite easy to detect, all that is necessary is to make a micro- 

 scopical examination of fresh blood films, a i in. objective will suffice. 

 Dried lilms, fixed and stained with any of the nuclear dyes. 



" The organism appears to be a strict parasite. It lives but a short 

 time after removal from the body, the longest time which it has been 

 kept alive in blood serum was not more than ten hours. 



"The parasite has many of the properities in common with the 

 filaria, and resembles more nearly that of filaria perstans, only it is 

 smaller, and its movements dissimilar. Vet on the other hand, the 

 clinical history of animals infested by it, the changes occurring in the 

 blood, the lesions observed in post-mortem, point very strongly towards 

 its classification with the spirochiete. 



" The mode of transmission has not yet been studied. It does not 

 appear to be highly contagious, as it does not appear to spread from one 

 to another, even under the most favorable circumstances. 



" It more nearly resembles malaria in this respect. It is more than 

 probable that its extra corporeal state is different, or another supposition 

 equally tenable, is that its intermediate host is some insect, such as the 

 fly or mcsquilo." 



§ 316. Differential diagnosis. Surra is to be differen- 

 tiated from anthrax and the other trypanosoma diseases. A 

 history of the case or outbreak together with the chronic 

 course and intermittent temperature in surra will usually 

 suffice to determine the nature of the disease. A positive 

 diagnosis can easily be made in the horse, in a majority of 

 cases, by a microscopic examination of the blood. The try- 

 pano.soma are readily observed, and usually they are in suffi- 

 cient numbers to be quickly seen. In a suspicious case, where 

 the organisms are not found, the examination should be 

 repeated daily or small animals inoculated with the blood. For 

 this ini'ect about i c.c. of the blood into the abdominal cavitv 



