SARCOSPORIDIA. 20/ 



The liberation of the Anuebula from the spore initiates the 

 first period of development, and is passed in the lymph spaces 

 of the intestine, and lasts some 28 to 30 days. For this reason 

 Sarcosi)()ridia have been classed as belonging to the suli-class 

 Neosp(tridia of the Sporozoa. Minchin says a ty])ical member 

 of the Neosporidia is a parasite of which the life cycle is ini- 

 tiated bv the liberation from the spore of one or more Amoebnlse 

 within the body of the host, in the digestive tract in all known 

 cases. In no case does it remain in the lumen of the digestive 

 tract, but ])enetrates into the wall of the gitt, and in most cases 

 migrates thence into some organ or tissue of the host, where it 

 lives and multiplies actively, being usually at this stage an 

 intracellular parasite. 



The second period of development begins with the pene- 

 tration of the Amoebulae into the muscle fibre, in which the 

 parasite grows into the Miescher's tube and forms spores. Ac- 

 cording to Negri, the intramuscular development of the parasite 

 begins by the multiplication of the nuclei to about 12. forming 

 a Plasmodium. According to Meischer, the ])lasmodial stage is 

 very characteristic of the subclass Neosporidia ; it represents 

 the princi])al or adult " trophic '' phase of the parasite, and is 

 also the spore-forming ])hase ; and, as the name Neosporidia 

 implies, the production of spores begins, as a rule, when the 

 Plasmodium is still young, and continues during its growth. 

 Further, Negri holds that the plasmodium next becomes divided 

 u]). in parasites about 30 days old, into scj^arate cells or sporants, 

 which multiply actively by division. This form of the parasite 

 now becomes elongated. This stage is reached at about 48 to 

 60 days. At this point the parasite may disintegrate, setting 

 free the sprouts, or may develope into a Meischer tube, (a) 

 In the first case the sporants wander out and establish themselves 

 in other muscle fibres, when its sporont initiates a fresh develop- 

 ment, (b^ In the second case a membrane is secreted round 

 the body, w^iich forms the striated envelope, prolonged inwards 

 to form the chambers. This body then consists of a peripheral 

 zone of sporants multiplying actively, and a central region in 

 which sporants are differentiated. In the development of the 

 spore, the sporant becomes sausage-shaped and multiplies by 

 division. Finally, the sausage-shaped bodies become spores, and 

 are stated to be at first binucleate — probably one nucleus is that 

 of the Amoebula, the other that of the capsulogenous cell. Fully 

 formed spores are found in the parasites from 80 to 90 days after 

 infection of the host. 



Symptomatology. 



As a rule the Sarcosporidia appear to be harmless parasites, 

 which do not make their presence known by any symptoms of 

 disease. However, a marked contradiction exists as to the 

 power these parasites possess in producing serious and recog- 

 nisable diseases. There are comparatively few instances in the 

 literature where symptoms have been observed during life of 

 an animal at post-mortem which has its muscles heavily infected 



