130 INFECTIOUS DISEASES DUE TO PROTOZOA 



spherical forms, karysome situated at edge of parasite; (2) large 

 and small pyriform parasites single and in pairs; (3) large and 

 small rod-like bodies, some of them extending across the entire 

 diameter of the corpuscle, sometimes in pairs; (4) rosette form, 

 consisting of four bodies connected in center by fine threads, 

 each body usually containing a karysome at its extremity; (5) 

 flagellate forms.* 



Laveran found multiplying forms more common in the spleen 

 than in peripheral blood. Multiplication is by direct division, 

 usually into two, sometimes into four bodies. The karysome 

 elongates, then divides into two parts; these separate, followed 

 by division of the cell body. The two parasites often divide giving 

 four, within the red corpuscle. Sometimes the karysome divides 

 into four parts before the protoplasm divides. The disposition 

 in fours is one of the most striking morphological characters of 

 Babesia equi (Laveran). 



The number of parasites in the peripheral blood varies a great 

 deal. They are present during febrile stages but disappear after 

 the fall of temperature. During the stage of high fever they are 

 numerous. Theiler has found them in unstained blood as abundant 

 as a parasite to five to 40 red corpuscles. Williams states that the 

 number of parasites in the peripheral blood is proportional to 

 the severity of the disease and that from one to 10% or up to 30% 

 of the corpuscles may be infected. Baruchello and Mori found 

 50-60% of the red corpuscles infected in some cases; they state 

 that the parasites are found most easily during the early stages of 

 the disease. The "rosette" form is present in varying numbers. 

 Sometimes the parasites are so scarce as to be found only after a 

 long search. After the administration of quinine the rosettes are 

 very scarce (Theiler). With the fall of temperature the number of 

 parasites decreases from day to day; by the time the temperature 

 has fallen they can be found only with difficulty. 



Changes in the blood. — The disease is characterized by a 

 progressive anemia. In the beginning of the disease the infected 

 red corpuscles ordinarily show no microscopical change; they are 



*Nuttall and Graham-Smith observed dumb-bell forms and fiagella like 

 processes while studying canine piroplasmosis. They found that these forms 

 and processes were due to overheating the red corpuscles and were able to 

 produce similar forms by overheating films of normal blood. 



