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R W Crosskey

Publications and source records attributed to R W Crosskey.

9 recordsLinked to original sources

A taxa summary for the Simulium damnosum complex, with special reference to distribution outside the control areas of West Africa.

A synoptic list is provided of currently recognized taxa in the Simulium damnosum complex, with an indication of their geographical distributions. Outline maps are given for the distribution of S. damnosum sensu lato, and for the West African cytospecies of the complex. Short reports on the identities and distributions of member taxa are given for countries other than those of the Onchocerciasis Control Programme in the Volta River Basin (OCP) and its Senegambia Extension; these are mainly based on collation of published and unpublished data for the post-1976 period (since the last WHO Expert Committee Report on Onchocerciasis).

Africa↗

The distribution of the Simulium damnosum complex in Sierra Leone and its relation to onchocerciasis.

Because of the paucity of literature concerning onchocerciasis and its vectors in Sierra Leone, new information of the geographical distribution of the Simulium damnosum complex is presented in the context of a comprehensive review of what is known generally about S. damnosum s.l. in Sierra Leone, and how the data relate to the transmission of onchocerciasis. Neither biting adults nor breeding sites have been found on the coastal plain and Freetown peninsula, and these area seem to be free from infestation. Throughout the rest of the country S. damnosum s.l. breeds extensively in all the major river systems. The close proximity of the major rivers to one another facilitates inter-river migration, and ensures that most villages are well within the fly's dispersal range. In accordance with this, onchocerciasis is widespread throughout Sierra Leone and vector biting has been recorded away from riverine breeding sites. Seven cytospecies have been recorded in Sierra Leone but of these S. sirbanum and S. damnosum s.str. are rare outside the far north, in the narrow savanna belt. Simulium squamosum and S. yahense are widely distributed, although S. squamosum is somewhat less common than S. yahense which unexpectedly occurs in large rivers of the forest and savanna as well as small forest streams. Simulium sanctipauli has been found in the south-east of the country, where the forest is most dense, whereas S. soubrense occurs farther north. A new species referred to as S. soubrense 'B' is restricted to the south and west of the country. Over most of Sierra Leone onchocerciasis shows a 'forest' epidemiology and is transmitted by 'forest' vector cytospecies. However, data from the narrow savanna belt in the extreme north are sparse.

Animals↗

A review of Simulium damnosum s.l. and human onchocerciasis in Nigeria, with special reference to geographical distribution and the development of a Nigerian national control campaign.

The confirmed geographical distribution of human onchocerciasis and its Simulium damnosum complex vectors in Nigeria is reviewed with the aim of defining the endemic zones of the disease relevant to the planning of a Nigerian national onchocerciasis control campaign. Five major endemic zones are recognized, a terminology suggested for them, their sizes estimated and the disease and vector situation within each zone briefly described; four of the zones are in savanna areas of the north, and the fifth in forest-savanna mosaic and forest areas of the south-west. Other areas where disease and/or vectors have been reported are briefly considered. Maps are given of known vector breeding sites, of disease distribution, and of the approximate extent of the anticipated control zones. The scanty available data on cytospecies identity of the vectors, vector biting rates, and Onchocerca volvulus transmission potentials, are reviewed, and it is stressed that acquisition of distributional data for the individual members of the S. damnosum complex and of ATP data is essential for the planning of control. An historical resumé, accompanied by a comprehensive bibliography of the published literature, of the work to date in Nigeria is included.

Animals↗