SARCOSPORIDIA. 



Bv GlLLES VAX DE W'aLL UK KoCK, M.R.C.V.S. 



Introduction. 



>iiKe the middle of 1914. the Sarcosporidia have come to 

 be regarded by the veterinarians in South Africa as the most 

 important groitp of organisms that may be responsible for disease 

 amongst some of the domestic animals. That this is the case 

 will be comprehended when the results of the recent researches 

 of Professor Hedinger into the disease lauiciektc amongst cattle 

 in South Africa are considered. The Professor holds that the 

 cause of the lesions in the muscular and nerv<3us systems of the 

 cattle that have died of lani:^icktc is considered to be due to the 

 action of the toxin and the presence of parasites in the muscular 

 fibres, which parasites belong to the group of he Sarcosporidia. 

 He thinks that the jM-esence of these Sarcosporidia ex])lain the 

 pathologx', clinical sym])toms, and epizoology of the disease. Can 

 Sarcos])()ridia be the cause of undoubtedly the most troublesome 

 and pt.M-lia])s the least understood of all South .\frican diseases? 

 Can it be true that these parasites arc responsible for the detri- 

 mental effects and financial depression in some of the best stock- 

 raising and cattle-rearing districts? 



Aioreover, McGowan. of the Koyal College of Physicians' 

 Laboratory, Edinburgh, in his investigations into the disease 

 amongst shee]) called scrapie, makes special reference to its 

 association with sarcosporidiosis. This disease has of late years 

 become widely known in some of the border counties of Scot- 

 land, and has only within the last few years, owing, possibly, 

 to it^ ra\ages and the conse([uent effects on the value of the 

 breeding stock, been more oj^eidy discussed. 



Of great interest is the fact that both Hedinger and 

 ]\lc(lowan. working on tw(» different diseases (one affecting 

 cattle, the other sheep; one occurring in South Africa, the other 

 in Scotland), arrived at more or less the same conclusions. What 

 raises further interest in this order is the fact that, although 

 Sarcos])oridia are verv common parasites of domestic animals, 

 yet our knowledge of their structure and life history is in a very 

 confused and incomjilete state. 



Classification . 



Sarcosporidia are protozoon organisms, and have been 

 generally given a ])lace in the class Sporozoa. However, the 

 jMiylogeny of the Protozoa is still a matter of s])eculation. and 

 to a large extent of i)er.sonal oi)inion. rather than direct obser- 

 vation, k-ven the class Protozoa in light of recent researches 

 ceases to be amenable to strict verbal definition, and it is not 

 surprising that the limits assigned to it have varied at dift'erent 

 times, and are now even debated (Minchin). The modern 

 tendencv is rather to split U]) the vast assemblage into smaller 

 groujx. and to abolish the Sporozoa as a primary subdivision. 



