CHAPTER VI 



PIROPLASMOSIS 



PIROPLASMOSIS as a destructive disease affecting cattle in Texas and 

 South America has been already mentioned in Part I. of this work, 

 and since the piroplasmata are growing in importance, it may be well 

 to recall the illustration of the parasites as seen in the red blood-cells 

 of cattle. Then I wrote, ' The history of the parasites whilst con- 

 tained within the tick has yet to be worked out.' This gap in know- 

 ledge has now been filled, S. R. Christophers 1 having traced almost 

 completely the life-history of Piroplasma canis ; and these important 

 observations are quite in accord with what is known of piroplasmosis 

 in other animals, and may be presumed to be the type for all. This 

 disease in dogs had been observed in Europe and Africa, and 

 Christophers met with the same disease in India. Different species 

 of tick are able to act as intermediate hosts for these parasites. In 

 South Africa, Lonusbury and Nuttall found that called H&maphysalis 

 leachi (Audouin) was concerned. In India Christophers found the 

 Rhipicephalus sanguinens (Latreille) was usually the carrier of the 

 disease, the infected adult female ticks giving rise to an infected 

 progeny. The larvae from eggs of an infected mother were found 

 not to be capable of transmitting this disease, whilst the nymphs 

 and adults of those same larvae were. Also previously uninfected 

 larvae were found to be infective when they reached the adult 

 stage after feeding on infected blood. The chief forms noted in this 

 brief paper are shown in Fig. 10, and may be classified thus : 



i. In the gut of nymph or adult fed on infected dogs were many 



1 S. R. Christophers, ' Preliminary Note on the Development of Piroplasma 

 canis in the Tick,' Brit. Med. Journ., January 12, 1907. 



