Probable Insect Vectors of Yellow Fever Virus, from Monkey to Man, in Bwamba County, Uganda

Abstract

The habits and habitations of the natives in the Bwamba lowlands, Uganda, are briefly described.A series of catches designed to assess the relative importance of the various species of biting insect and of various routes of transference in the transmission of yellow fever virus from the monkey population of the forest to the nearby human population is reported.The microclimate in a native hut is discussed.The species of biting insect encountered are listed, the results of the catches given, and the relative importance of the different species and routes assessed by means of indices.It is concluded that yellow fever virus is most likely to be transferred to the native population by A. (S.) simpsoni in plantations, the infection in this insect being derived from forest monkeys which raid the plantations for food.

The Activity Cycle of domestic Aëdes (Stegomyia) aegypti (L.) (Dipt., Culicid.) in Southern Province, Tanganyika

“…The microclimate of hut interiors has been studied by Haddow (1942) and Lumsden (1951). As far as temperature and humidity are concerned, conditions inside a hut tend to be more equable than in the open.…”

Field and laboratory studies on an African monkey, Cercopithecus ascanius schmidti Matschie.

“…This is to be accounted for by the fact that during the resting-period the monkeys frequent the denser foliage and are then much more difficult to see than when they are active, a fact also noted by Buxton (in press). It is interesting to note that even in captivity C. a. schmidti does not lose this general rhythm of two active periods with a quiescent phase between (Lumsden, 1951 a). While the second feeding-period begins shortly after midday, it is not in full swing till about 15.00 hours, from which time it continues very steadily -X _ -_ --.…”

“…I n the vast trees of the rain-forests there is ample room for a band of this size to break up into numerous quite separate sleeping-parties. This view is borne out by the fact that a single tree may give night-harbourage to monkeys of more than one species, though this is unusual (Lumsden, 1951 a). In addition to Lumsden's records, the writer has noted a case where bands of C. albigena johnstoni and C. abyssinicus ituricus slept in a single huge tree on more than one night, the number of monkeys being approximately thirty.…”

“…For reasons which will become apparent below, it is also important to note that A . sirnpsoni may be taken biting in the forest canopy, though this is not its usual habitat (Haddow, 1950 ;Lumsden, 1951 b). It is further to be noted that A .…”

“…Their use in the laboratory was a t first largely confined to studies on the virus diseases, but more recently monkey filariasis and the monkey malarias have become important in relation to chemotherapeutic studies designed to test new drugs intended for human use. It appears, therefore, that studies on monkeys in their natural habitat are, at the moment, most desirable, and recent work such as that of Lumsden (1951 a) and Buxton (19.51,and in press) has shown clearly how much information may be gained by simple methods, and also serves to emphasize how much remains to be learned about the .4frican monkeys in general.…”