284 



Development in the Tick. P. parvum passes through 

 similar changes to P. bigeminum as far as the forms 

 depicted in Fig. 91, but the amoeba-like forms 

 (Fig. 91 (4) ) have not been seen. 



3. P. annulatum (Dschunkowsky and Luhs). In 

 cattle in Transkaukasia and Egypt. 



Symptoms. (i) Acute form : daily rises of tempera- 

 ture to 41 for one to two weeks. Temperature then 

 remains high. Pulse one hundred and twenty, thread- 

 like. Respirations thirty-six. Haemoglobinuria seldom. 

 Convulsions. Death. (2) Chronic form : characterised 

 by icterus and progressive weakness and great anaemia. 



Blood Examination. Acute form : over ninety 

 per cent, of the red cells are infected. Bacillary and 

 ring forms occur. Chronic form : ten to forty per cent, 

 of cells are infected, and only cocciform or punctiform 

 parasites are found. 



Pathology. Extensive haemorrhages in most 

 organs. In the abomasum (fourth stomach) occur 

 characteristic haemorrhagic ulcers. Cp. P. parvum. 



Transmission. (i) Susceptible cattle can be 

 infected by inoculation. (2) The carrier is M. calca- 

 ratus, a variety, according to Donitz, of M. annulatus. 



4. P. mutans (Theiler). In cattle in the Trans- 

 vaal, in the blood together with P. bigeminum. Differs 

 from this by the fact that it produces minute bacillary 

 and ' cross ' forms as is the case with P. parvum, but 

 is not the same as this though morphologically very 

 similar ; as it is inoculable. P. annulatum is separated 

 by its morphology and pathological effects. In order 

 to distinguish from P. parvum, several blood examina- 

 tions must be made ; this form increasing rapidly in 

 numbers, while P. mutans is always scanty. 



Transmission. By inoculation of blood. 



Similar associations of P. bigeminum and bacillary 



