THE CATTLE WORM-NODULE PARASITE. 
The Cattle Worm-Nodule Parasite.” 
Some Experiments with Flies as possible Transmitters. 
By Professor T. HARVEY’ JOHNSTON and M. J. BANCROFT, Walter and. 
Eliza Hall Fellow in Economic Biology, University, Brisbane. 
Although a considerable amount of work has-been carried out by 
various Australian investigators with a view to ascertaining how cattle 
become parasitized by Onchocerca gibsoni, Cleland and Johnston—the 
organism which produces “ worm nodules ”’—vwe are still ignorant as to 
what is the transmitting agent. The prevailing idea is that a Tabanid 
fly is responsible, though a number of workers, including Cleland, Breinl, 
Hill, McEachran, and others, have used such flies unsuccessfully. 
Marcu F rites. 
’ 
We have attempted to infect various March flies in the Upper 
Burnett River district, Queensland, during 1918 and 1919, by allowing 
them to feed on freshly-cut living worm nodules. Of course, one must 
admit that this is quite an unnatural method as far as the transmitter 
is concerned, since most of the embryos or larve liberated from the 
female by this means are’ probably not in a fit state to commence their 
development in the intermediate host, though some would, no doubt, be 
ready to do so. 
The species used were Vabanus circumdatus, T. australicus, T. 
mastersi, and 7’. dubiosus. Though they were examined at intervals 
varying from one to ten days after such feeding, no development of 
the larve taken up by them had occurred, and in only one case was a 
living larvee found in a ‘fly’s alimentary canal one day after feeding. - 
The tissues of each fly were carefully examined, and, though certain 
other filarial worm larve were found, no trace of Onichocerca was 
detected. 
On account of the presence of Onchocerciasis in local cattle, it was 
thought that an examination of captured Tabanids might yield informa- 
tion. Five hundred were caught and carefully searched between Novem- 
ber, 1918, and January, 1920, but the results were negative, though, as 
already stated, another parasite, Agamofilaria tabanicola, Johnston and 
Bancroft, was detected in nearly 4 per cent. of the specimens of 7. cir- 
cumdatus examined. This is by far the commonest local March fly. 
Specimens of 7’. australicus, T. mastersi, T. cyaneus, and T..dubiosus, 
were also searched for the presence of worm parasites, but without 
success, the numbers examined being, however, comparatively few. 
* Abstract of a paper by T. H. Johnston and M. J. Bancroft, ‘‘ Experiments with certain 
ayn as possible transmitters of bovine Onchocerciasis.” Proc. Royal Soc. Queensland, 32, April, 
1920, p. 31. : 
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