The trypanosome diseases form the best example of this mode of transmission.
Another striking example and one that is attracting world-wide attention just now is the trypanosome that is causing such devastation among the inhabitants of central Africa.
This rat trypanosome is transmitted by fleas and lice.
It is a matter of great interest that a trypanosome has been found in a death-stricken herd of European bison.
Some weeks later they evolve into the trypanosome forms, pathogenic for man.
Trypanosoma lewisi, the first mammalian trypanosome known, is to be found in the blood of wild rats.
The horse-flies have been definitely convicted of transferring the trypanosome of surra from diseased to healthy animals and there is good evidence that they transfer anthrax.
This trypanosome Bruce had discovered in the blood of South African cattle suffering from a highly fatal disease known as "nagana".
As in the case of nagana, Bruce and most of the earlier investigators supposed the transmission of the sleeping sickness trypanosome by Glossina palpalis to be purely mechanical.
The tsetse flies, belonging to the genus Glossina, are African species of blood-sucking Muscidae which have attracted much attention because of their role in transmitting various trypanosome diseases of man and animals.
He also cites the trypanosome diseases as possible exceptions, since the causative organisms apparently thrive in a number of different vertebrate hosts and may be transmitted from cattle, or wild animals, to man.
Darling (1913) has shown that murrina, a trypanosome disease of horses and mules in the Canal zone is transmitted by house-flies which feed upon excoriated patches of diseased animals and then pass to cuts and galls of healthy animals.
Atkinson has found a trypanosome in the fish--it has been stained, photographed and drawn--an interesting discovery having regard to the few species that have been found.
