(t. H. F. Nuttall 
307 
B. decoloratus. Ph'oplasma hovis is widely distributed in warm 
countries and the tropics—it occurs in N. and S. America, Australia, 
Asia and Africa, and occasionally in Southern Europe. Redwater has 
been repeatedly reproduced experimentally by means of larval Boophilns, 
the progeny of ticks which have sucked the blood of animals suffering 
from redwater. This form of piroplasmosis has been the cause of great 
financial losses, it having been estimated that in the United States alone 
the annual loss has amounted to forty million dollars. 
Equine Piroplasmosis. 
Redwater, or “biliary fever” in horses, as I have shown with 
Strickland, is due to two parasites which are morphologically distinct ; 
Nuttallia equi (Laveran), of which I shall speak presentl}^ and Piroplasma 
Nuttall (Fig. -i), the cause of true piroplasmosis in equines. When 
/J 19 - '7 
Fig. 4. Piroplasma cahalli, showing the same mode of multiplication 
as P. canis. (Nuttall and Strickland, 1912.) 
a horse “ recovers ” from P. cahalli infection it is still susceptible to 
N. equi infection. Piroplasma cahalli occurs in Russia, Rou mania, in 
Transcaucasia, and apparently extends across Siberia. Dermacentor 
reticulatus has been shown by experiment to transmit the disease, 
and this tick is distributed over the geographical area mentioned, 
besides occurring in Western Europe, including Great Britain, where 
