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PIROPLASMA MUTANS INFECTION. 



A disease of cattle, due to the presence of Piroplasma mutans 

 either naturally contracted by ticks or artificially by the inoculation of 

 blood containing this parasite has, as a rule, a chronic course, micro- 

 scopically pronounced as an anemia. Recovery is usual, and recovered 

 animals are known to be immune. 



The Blood of Immune Animals. — Blood of an animal which has 

 shown the presence of Piroflasma mutans at one time, either due to artificial 

 or natural infection, is infective for susceptible cattle when inoculated. 



The experiments never failed when animals were used of a country 

 known to be free of Piroflasma mutans infection and the blood used for 

 inoculation was derived from an animal in whose blood Piroflasma mutans 

 have been traced ; whilst animals immune against redwater as a rule do 

 not show the presence of Piroflasma bigeminum^ in microscopical examina- 

 tions ; this is the rule with Piroflasma mutans, which for a long time 

 can be traced microscopically. 



Immunity under Influence op Intercurrent Fever. — The number 

 of these parasites undergo variations and, similar to redwater, the 

 existence of another febrile disease can evoke an increase of parasites. 



Two head of cattle used in a heartwater experiment developed a 

 typical heartwater leaction, due to the virus injection, and during this 

 reaction Piroflasma mutans increased considerably. A similar observa- 

 tion was made in an ox which contracted heartwater naturally. 

 Usually the presence of Piroflasma mutans is accompanied with that 

 of Piroflasma bigeminum, which can easily be imderstood, since every 

 animal born on the Transvaal veld is immune against redwater. We 

 succeeded, however, in finding an animal which was infected with Piro- 

 flasma mutans alone, and, in the course of the various experiments, twenty- 

 six animals were injected with blood of recovered animals and all showed 

 pure Piroflasma mutans reactions. 



Conclusion. — The blood of an immune animal which recovered from 

 mutans infection remains infective. Similar to Piroflasma bigeminum 

 and equi, intercurrent fevers can cause an increase of Piroflasma 

 mutans, which can be considered as a decrease in the existing 

 immunity. 



PiROPLASMOSIS OF THE DoG. 



Canine piroplasmosis is due to the infection with Piroflasma canis, 

 introduced into susceptible dogs either naturally by means of ticks 

 (Haemafhysalis leachi) or artificially with blood which contains the para- 

 site. The disease has a relapsing character. 



The final recovery renders a dog immune. This immunity in an 

 experiment of ours by inoculation with virulent blood of one and the 

 same strain could not be broken. 



