Some Experiments with Arsenphenylglycin and Trypanosoma gambiense in Glossina palpalis

H. L. Duke
1912 Proceedings of the Royal Society of London. Biological Sciences  
The experiments detailed below were devised with a view to investigating the action of arsenic in the form of arsenphenylglycin upon Trypanosoma gambiense as carried by Glossina palpalis. It was found convenient to deal with the subject under four separate enquiries-I. Does the presence of arsenic in the blood ingested by a positive fly destroy the trypanosomes in that fly ? II. Does preliminary feeding of flies on blood containing arsenic have any effect on the subsequent development of
more » ... velopment of trypanosomes in their interior ? III. If flies are fed on blood containing arsenic shortly after the infecting feeds on a gambiense monkey, are the flagellates still capable of development in the fly ? If they can still develop, is the resultant strain arsenic-resistant in the blood ? IV. Has arsenphenylglycin any prophylactic action against the bite of a fly infected with T. gambiense, and, if so, what is the e protection ? In all these experiments it was deemed advisable to feed each box of flies for two consecutive days on the monkey in order to make certain, if possible, that each fly fed. For the same reason special attention was given to each box of flies handled, with the result that it was found that flies reluctant to feed in the morning would often, if given another opportunity some hours later, bite with greater readiness. In spite, however, of all precautions, it is impossible to be absolutely certain on this point. In the great majority of cases the flies fed readily every day. I. Does the Presence of Arsenic in the Blood imbibed clean an Infected Fly of its Flagellates ? To answer this query boxes of laboratory-bred G. palpalis, known to be infective with T. gambiense, were placed upon monkeys which had previously received a subcutaneous dose of arsenphenylglycin, OT grm. per kilogramme body weight. The experiments were commenced 24 to 48 hours after the administration of the drug, and subsequently the period of time was increased. No change in the flagellates was dis cernible if the interval between the giving of the arsenic and the feeding exceeded 72 hours. The flies were dissected by Miss Robertson at c 2
doi:10.1098/rspb.1912.0089 fatcat:bd6sdi5ntreyjnwvad435twd6u