2Q2 



THE PROTOZOA 





The cause of this disease is B. bovis (B. bigemina) and the parasite is transmit 

 by a tick, Mar gar opus annulatus. There is also a disease of dogs called malignant 

 jaundice of dogs which is caused by B. canis and also transmitted by a tick. Organ- 

 isms of this kind have been thought of in connection with blackwater fever of man. 

 Seidelin has claimed that a parasite of similar nature, Paraplasma flavigenum, was 

 the cause of yellow fever. 



At one time spotted fever of the Rocky Mountains was supposed to be due to a 

 parasite named Babesia hominis. The parasite of Oroya fever is 

 probably protozoal in nature. It is found in red cells as rod- 

 like bodies and is called Bartonella bacllliformis . See Oroya 

 fever. 



SARCOSPORIDIA 



Sarcosporidia are sporozoa found in the striped 

 muscles of various mammals and birds. They are 

 common in the pig and mouse and have been re- 

 ported for man in three well-authenticated cases. In 

 the last, Darling found these protozoa in the biceps 

 muscle of a negro patient in Panama. In Baraban's 

 case the laryngeal muscles at autopsy were found 

 to show cysts about Jf 5 inch long which contained 

 sickle-shape sporozoites about qn long. 



FIG. 63. Mie- They are known also as Miescher's tubes when in muscle fibers, 

 scher's sac from They are divided into three genera: Miescheria and Sarcocystis 

 olTa 'ho 501 * 1 X U1 Q when P arasitic "* musc l e fiber J Balbiania, when parasitic in the 

 diameters. (After intervening connective tissue of the muscles. The method of 

 Ostertag.) transmission is unknown. In some places more than 50% of 



the sheep and pigs may show infection. 



Miescheria has a thin membrane surrounding the cyst while that of Sarcocyslis 

 is thickened and radially striated by small canaliculi. 



As the young trophozoite grows nuclei increase and a definite membrane forms 

 which the sporoblasts eventually fill. According to Minchin the Sarcosporidia con- 

 tain only one genus, Sarcocystis. It is never parasitic for invertebrate hosts and 

 while occasionally found in birds and reptiles it is preeminently a parasite of the 

 higher vertebrates. As a rule, they are harmless parasites but the Sarcocystis muris 

 is very pathogenic for the mouse. Closely related to the order Sarcosporidia is the 

 parasite Rhinos poridium kinealyi. 



Rhinosporidium kinealyi. It causes pedunculated tumors of nasal cavity. The 

 pansporoblasts enlarge in the center of the connective tissue of the nasal polyp and 

 contain about 12 sporoblasts. When mature the cystic-like polyp bursts and the 

 sporoblasts are liberated to extend the infection. 



