Flies and Disease--Biology and Disease Transmission

Abstract

In the context of these books, " Flies" virtually means cyclorrhaphous Diptera, a fascinating and evolutionarily highly successful group of insects. There are, for example, more of these species in Britain than all other exopterygote insects together. A considerable number of these flies have developed various relationships with higher vertebrates, including man and his domestic animals. The larval stages may feed on animal faeces (or decaying vegetation enriched with excreta), or in cadavers, or in wounds and sores, or they may pierce skin and breed in flesh. The adults may merely take advantage of human shelters and feed on man's foodstuffs, or may feed on bodily exudations (sweat, conjunctival fluid) or on blood. Flies with any of these associations with man are described as synanthropic; and many of them take part in transmission of various pathogens. Unlike the sole and specific disease vectors of such disease as malaria, flies are only one of several modes of transmission in these cases. It is by no means easy to assess the relative importance of " finger, faeces, food and flies " in the carriage of some important enteric and ophthalmic infections. The subject was discussed as long ago as 1913 [Flies in relation to disease, this Bulletin, 1913, v. 2, 655] by GRAHAM-SMITH. The pre-eminent role of houseflies was also considered in an excellent book by C. G. HEWITT (Houseflies and how they spread disease, Cambridge Univ. Press, 1914) and a more recent one by WEST [this Bulletin, 1952, v. 49, 735]. The present pair of books is the most complete and up-to-date account which could be desired. They do not, however, deal with myiasis, nor very extensively with the biology of the housefly, on the grounds that these subjects are adequately covered respectively by ZUMPT'S Myiasis in man and animals in the Old World [ibid., 1965, v. 62, 483] and WEST'S The housefly [loc. cit.]. Volume I is said to be a detailed reference book which grew out of the primary account in Volume II. It contains some 80 readable pages by European experts on the ecological aspects of fly associations. The first, by a Czech (Dalibor POVOLNY) is rather heavily loaded with terms like " anthropobiocoenosis ", which may appeal to " neopolysemantophilists " but not to the reviewer. The next chapter, on the bionomics of the more important flies, is largely repeated and amplified in Volume II. There follow about 80 pages of systematic keys, with 15 superb colour plates of important species. …