24 
NOTES ON THE COMMON PATHOGENIC 
Species. 
Sp. Theileri. Laveran, 1903. 
Hosts. Cattle. 
Distribution. This parasite was first found in the Transvaal. 
It has been found in cattle in East Africa. 
Morphology. Sp. Theileri measures from 20ya to 30 /a in 
length, and rather over 1ft in thickness. The number of 
curves is variable, being on an average about 8 to 10. 
Transmission. Laveran and Vallee succeeded in infecting 
a cow in Paris with the larvae of the South African Blue Tick 
(Boophilus decolor atus) sent from Pretoria. Theiler’s first 
attempt to reproduce infection by the inoculation of blood 
was negative. Subsequent experiments, however, have shown 
that the parasite can be transmitted in this manner. 
Pathogenesis. Little is known of the disease caused by 
this parasite. In South Africa it is associated with one of 
the forms popularly referred to as ‘ Gall Sickness.’ In East 
Africa it has been found in cattle which are manifesting a 
pronounced anaemia. The blood of an animal which has 
recovered from the disease still contains the parasite, though 
it may not be detectable under the microscope, and such 
an animal may serve as a reservoir for the transmitting tick. 
Spirochaeta have also been found in the horse (Sp. equi) and 
in the sheep (Sp. ovina) in Africa. Stordy was the first to 
describe the former in East Africa. The latter is said to be 
fairly common in Erythrea and Abyssinia. Nothing is known 
as to the transmission of these species. 
Sp. g allinarum. B. Blanchard. 
Hosts. Domestic fowls, also in pigeons, geese and ducks. 
Morphology. Measures about 20/-& in length. 
Transmission is effected by means of one of the ticks 
belonging to the sub-family Argasidce. The appearance and 
habits of these ticks are dissimilar to the commonly known 
species. In shape they are more like a wood louse, and in 
habits they are mainly nocturnal. They usually attach 
themselves to an animal for a few hours, during which time 
they feed, and then drop off and retreat to a hole or crevice in 
