PROTOZOA IN BRITISH EAST AFRICA 
89 
for doubt that it will find a place in the order Haemosporidia. 
In anticipation of this it is discussed here. 
Hosts. Up to now cattle alone have been found to harbour 
the parasite. 
Distribution. Anaplasma apparently has a wide geo- 
graphical distribution — America, North and South, Trans- 
caucasia, and it has been detected in all parts of Africa where 
systematic examinations of blood were made. In East Africa 
we have noted it principally around Nairobi and Naivasha, 
possibly as these districts possess a good proportion of grade 
and pure bred cattle which are more susceptible than, native 
stock. Theiler found it present in slides from Uganda. 
Morphology occurs as rounded or ovoid bodies of about 
l/i in diameter ; no definite structure can be made out by 
Romanowsky staining, the whole body taking a deep modified 
chromatine tint. They are most frequently situated at the 
periphery of the red blood corpuscles — hence the specific name. 
Transmission. Theiler has shown that the common blue 
tick (Boophilus decoloratus) can carry the parasite. As is 
the case with B. bigemina and the same tick, the organism 
passes through the egg of a mother fed upon an infected 
animal. 
Pathogenesis. The early workers on Redwater in cattle — 
Smith and Kilborn, Lignieres, &c. — noted the occurrence of 
* peripheral coccus-like bodies ’ which were regarded as a 
form of B. bigemina associated with a relapse of the disease. 
To Theiler belongs the credit of proving that these parasites 
are distinct zoological entities. Anaplasma is connected with 
one of the many diseases commonly grouped by the lay mind 
as 4 Gall sickness ’ ; Babesia mutans is responsible for another 
form of this same condition. It can be conveyed by the 
inoculation of blood taken from a sick animal, and also, as is the 
case with Babesia and Nuttallia, with the blood drawn from 
a recovered animal. 
