Abstract
DR. E. WABREN, director of the Natal Museum, has reported, according to a message in the Times of March 10, that experiments carried out by Mr. Davidson, an independent naturalist, “completely destroy the theory at present accepted about the reservoir of infection from which the tsetse fly transmits the widespread cattle disease known as Nagana”. It is generally accepted—and has, in fact, been repeatedly proved—that the blood of game animals harbours trypanosomes which, when conveyed to domestic animals by the tsetse fly, give rise to the serious and often fatal diseases which are grouped under the term ‘nagana’. Mr. Davidson now claims to have shown that the trypanosome responsible is derived from the latex of certain plants “on which the tsetse fly normally feeds”. Further information on these observations (which appear to have satisfied Dr. Warren, by whom they have been “carefully checked”) will be awaited with much interest. It is well known that leptomonad-like flagellates are common in the latex of Euphorbia and other plants, being transmitted from one plant to another by certain plant-sucking bugs; but no evidence has as yet been published that these organisms can cause disease in vertebrates; and up to the present time no trypanosome has ever been discovered in a plant. The tsetse fly has occasionally been observed to plunge its proboscis into certain fruits, but in the past it has seemed very doubtful if these constitute a regular source of food supply.
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Source of ‘Nagana’ in South Africa. Nature 129, 429 (1932). https://doi.org/10.1038/129429b0
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DOI: https://doi.org/10.1038/129429b0