The Transmission of Bancroftial Filariasis on Ukara Island, Tanganyika. I.—A Geographical and Ecological Description of the Island with an annotated List of Mosquitos and other Arthropods of medical Importance

Abstract

A description is given of Ukara Island, which lies in the Tanganyika part of Lake Victoria, with an annotated list of mosquitos and other arthropods of medical importance found there. There are also notes on local plants and vertebrates. The inhabitants, called Bakara, live in cone-shaped grass huts over 20 ft. in height and diameter. People and cattle are housed together. The area of the island is about 45 sq. miles. The 17,000 inhabitants, almost entirely African, support themselves by advanced agricultural practices involving the use of manure and nitrogenous plants. There is a coastal belt of intense cultivation and a large central area of uninhabited grassland with extensive deep erosion. The beds of rivers which radiate from the centre are occupied by large irrigated areas. Seasonal fluctuations in lake level have little effect in general on cropping practices which are affected more by seasonal variations in rainfall. The average rainfall for 1950–52 was 62 inches per annum. Temperatures are equable throughout the year. Mean maxima for 1953 were 81°F. for April, 83°F. for May, 82°F. for June and 81°F. for July—mean minima were 70°F. for April, 68°F. for May, 69°F. for June and 67°F. for July. Wind velocities, recorded at noon, vary between 4·8 metres per second in June and 2·4 in January.