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COMMUNICATIONS 
The influence of cold on ticks 
and Piroplasma parvum 
By A. TH El LE R. 
Shortlv after the introduction of East Coast Fever into the 
low-veld of the Elands River Valley in the Eastern Transvaal, 
and before législation prohibited the movement of cattle, in seve- 
ral instances infected herds were brought up from that district to 
the high veld. One particular case came under my observation 
in the neighbourhood of Carolina. It was generally noted that 
directlv after the introduction of sick cattle to the high veld, the 
infected cattle died ont, and the remainder of the herd did not 
contract the disease, neither did the cattle which were grazing on 
areas over which the infected cattle must hâve dropped ticks. At 
that time it was not known that Rhipicephalus evertsi (the red 
tick) was a carrier of East Coast Fever, and the observation was 
apparently explained since Rh. appendiculatus (the brown tick) 
which is the principal carrier of the disease, was not found 
amongst the surviving cattle at the time the examination was 
made, and it was therefore concluded that Rh. appendiculatus 
could not live in the high-veld. 
Later investigations however, proved that Rh. appendiculatus 
may live in the protected places in very high altitudes such as 
dongas, but it is not présent in large numbers. In 1906, 
Mr. Lounsbury, Governement Entomologist of the Cape Colony, 
stated that Rh. evertsi was also a carrier of this disease, and in 
a former communication (1) I was able to corroborate this state- 
ment with the réservation that Rh. evertsi is not such a certain 
carrier of Piroplasma parvum as the brown tick, as in several ins¬ 
tances I failed to infect Rh. evertsi. 
(t) Annual Report. T906-7. 
