BABESIA. 315 



present in large numbers in a cell, the shape varies from 

 a long oval to pyriform or circular. The merozoites are set 

 free by the rupture of the corpuscle and infect other corpuscles. 



Remarks. — Patton (1910) believed, that the hounds got the 

 infection from the jackal. He demonstrated the same 

 parasite in the blood of the jackal, and showed that the 

 infection could be transferred to dogs my means of inoculation 

 of blood from the infected animal. Dogs which had recovered 

 from B. canis were inoculable with B. gibsoni. He suspected 

 Bhipicephalus sp., a species related to Rhipicephalus simus 

 (Koch) which occurs on the jackal, as the transmitting agent. 

 Baldrey (1911) thought that the outbreak described by 

 Patton as due to this species was of the same nature as that 

 previously described by Pease and Gunn (1908), and that the 

 form is not morphologically distinct from Babesia tropicus 

 (Lingard & Jennings, 1904). Lingard and Jennings studied 

 piroplasmosis in different animals, but probably confused 

 a number of species, and B. tropicus is not now recognized 

 as a distinct species. 



Rau (1927) observed that smears from engorged larvae of 

 the tick, Hssmaphysalis bispinosa Neumann, showed some 

 parasites with fibrillar prolongations and a few free large 

 rings. Transmission experiments with H. bispinosa were 

 inconclusive. Cultivation of the parasite in vitro was also 

 not successful. The blood from an infected jackal when 

 injected into a dog gives the disease to it and vice versa. 

 In the dog, however, the disease takes a more acute form than 

 in the jackal. 



According to Stirling (1929) the infection caused by this 

 much smaller piroplasm differs clinically from that caused 

 by P. canis in being usually more prolonged in its effects. 

 The symptoms are generally those of a progressive anaemia 

 with frequent tendency to relapses at prolonged intervals. 

 It does not respond to treatment with trypan blue, but good 

 results have been obtained by repeated treatment with certain 

 arsenical preparations, notably tryparsamide. 



Swaminath and Shortt (1937) have shown that the jackal- 

 tick, Hsemaphysalis bispinosa Neumann, is a vector of 5. gibsoni, 

 and that all stages of the tick can transmit. Hereditary 

 transmission through the egg also occurs. 



Ray and Idnani (1938) have recently made a detailed study 

 of B. gibsoni in the Vertebrate host. They found two types 

 of parasites, viz., ring forms and thin elongate forms, in 

 smears from the peripheral blood as well as internal organs. 

 The ring forms were found to multiply by repeated binary 

 fission until 12 to 16 merozoites were formed ; while the 

 thin elongate forms were observed to multiply in a manner 

 which suggested a process of schizogony and gave rise to 



