The occurrence and distribution of Simulium species in Ife, Ijesa and Ondo divisions
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Date
1985
Authors
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Publisher
Obafemi Awolowo University, Ile Ife, Nigeria
Abstract
have been investigated for the presence of the larvae of the blackfly Simulium. The larvae were
collected from thirty chosen stations of the river systems and identified in the laboratory. Water
samples from each site were also taken and analysed in the laboratory.
The main features used in identification of the larvae were the external characters especially the
presence or absence of dorsal conical tubercles and ventral papillae, pattern of respiratory
histoblast and body shape. Larvae of seven species of Simulium were identified.
These were S. alcocki, S. johannae, S. impukane, S. schoutedeni, S. griseicelle,L S. griseicolle
form tridens, and S. damnosum s.l.. S. alcocki and S. griseicolle were well distributed in the area
of study while S. damnosum was found at only five sites. It appears that there is one main area of
Simuliid breeding located in the southern part of the area of study and concentrated around River
Oni, River Awo and River Owena.
At the points where the larvae were found these rivers are mostly swiftly flowing and with rocky
beds. Three of the sampling stations, one on River Oshun and the other two on River Oni, were
found to have hydrochemical conditions which were conducive to the breeding of cytospecies of
S. damnosum s.l. which can transmit human onchocerciasis. These hydrochemical conditions
include pH and conductivity.
The need to carry out more work on the distribution of Simulium larvae and the rhydrochemical
properties of rivers and streams in the southern parts of Nigeria is suggested.
Description
67p
Keywords
Rivers, Streams, Larvae, Dorsal conical tubercles, Body shape, Hydrochemical conditions, Onchocerciasis, Conductivity