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glands are enlarged and haemorrhagic ; (3) Infarcts 
occur in the liver, lungs and kidneys. These changes 
are mainly due to injury caused by the collection of 
large masses of parasites. 
Transmission. —(1) The disease is not transmissible 
by inoculation. Eu. appendiculatus, the brown tick; 
and Eu. simus are known carriers. Larvae which have 
fed on infected animals transmit the disease in the 
nymphal stage only. Nymphs which have fed on 
infected animals transmit in the adult stage only. 
The transmission is accordingly not hereditary. The 
blood of recovered animals is not infective as in the 
case of P. bigeminum. 
Life history of Eu. appendiculatus with three hosts, 
i.e.j changes after the larval and nymphal stage. 
Eggs on grass, According to tempera- 
hatch in ture and moisture ... 28 days. 
Larvae remain on 
grass till they 
find a host. 
On cattle. 
Host No. I. Take in¬ 
On grass. 
fection 
Dormant, first moult 
3-4 days. 
takes place ... 
Host No. II. Give in¬ 
21 days. 
Nymphs on cattle. 
fection and take infec¬ 
tion ... 
3-4 days. 
On grass. 
Dormant, second moult 
takes place ... 
18 days. 
Adults on grass. 
On cattle. 
Host No. III. Give in¬ 
fection. Copulation. 
2 drops off ... 
4 days. 
2 on grass. 
Egg-laying begins in ... 
6 days. 
(Some thousands laid.) 
