
AMERICAN MUSEU./ GUIDE LEAFLETS 

OTHER DISEASES TRANSMITTED BY ARTHROPODS 
In addition to the insect-borne diseases mentioned above, there 
are many other diseases of tropical countries, which are transmitted in 
a similar way by insects or by their relatives, the ticks. Among the 
most important of these are sleeping sickness and other diseases 
caused by the Protozoan parasites of the genus 77rypanosoma, and 
transmitted by the biting flies of the genus G/ossina, and certain 
forms of relapsing fevers and similar maladies, caused by spirochetal 
parasites transmitted by ticks. 

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Fig. 34. DISTRIBUTION OF TEXAS FEVER OF CATTLE AND 
ROCKY MOUNTAIN TICK FEVER 
The ticks are not insects at all but belong to the Acarina or mites 
(see page 4). The first of all the arthropod-borne diseases to be 
definitely worked out was the serious cattle plague, known in our 
Southwestern States as Texas fever and in Australia as redwater 
fever. In 1889 Smith and Kilbourne showed that the causative agent 
in this disease was a Protozoan parasite ( Babesia) and that it was carried 
by the bite of a tick, Boophilus annulatus. Rocky Mountain spotted 
fever, which attacks visitors to the Bitterroot Valley and other areas 
in the Mountain States, is spread by Dermacentor andersoni and other 
ticks. The most terrible of tick-borne diseases, however, are the 
African tick fevers or relapsing fevers caused by different species of 
spirochetes. 
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